# Source code for coords

```
#
##
## This file is part of pyFormex 2.0 (Mon Sep 14 12:29:05 CEST 2020)
## pyFormex is a tool for generating, manipulating and transforming 3D
## geometrical models by sequences of mathematical operations.
## Home page: http://pyformex.org
## Project page: http://savannah.nongnu.org/projects/pyformex/
## Copyright 2004-2020 (C) Benedict Verhegghe (benedict.verhegghe@ugent.be)
## Distributed under the GNU General Public License version 3 or later.
##
## This program is free software: you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation, either version 3 of the License, or
## (at your option) any later version.
##
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with this program. If not, see http://www.gnu.org/licenses/.
##
"""A structured collection of 3D coordinates.
The :mod:`coords` module defines the :class:`Coords` class, which is the basic
data structure in pyFormex to store the coordinates of points in a 3D space.
This module implements a data class for storing large sets of 3D coordinates
and provides an extensive set of methods for transforming these coordinates.
Most of pyFormex's classes which represent geometry (e.g.
:class:`~formex.Formex`, :class:`~mesh.Mesh`, :class:`~trisurface.TriSurface`,
:class:`~plugins.curve.Curve`) use a
:class:`Coords` object to store their coordinates, and thus inherit all the
transformation methods of this class.
While the user will mostly use the higher level classes, he might occasionally
find good reason to use the :class:`Coords` class directly as well.
"""
import numpy as np
from pyformex import arraytools as at
from pyformex import utils
__all__ = ['Coords', 'bbox', 'bboxIntersection', 'origin',
'pattern', 'xpattern', 'align']
###########################################################################
##
## class Coords
##
#########################
#
[docs]class Coords(np.ndarray):
#
# :DEV
# Because we have a __new__ constructor and no __init__,
# we have to put the signature of the object creation explicitely
# in the first line of the docstring.
#
"""Coords(data=None,dtyp=at.Float,copy=False)
A structured collection of points in a 3D cartesian space.
The :class:`Coords` class is the basic data structure used throughout
pyFormex to store the coordinates of points in a 3D space.
It is used by other classes, such as :class:`~formex.Formex`,
:class:`~mesh.Mesh`, :class:`~trisurface.TriSurface`,
:class:`~plugins.curve.Curve`, which thus inherit the same transformation
capabilities. Applications will mostly use the higher level
classes, which have more elaborated consistency checking
and error handling.
:class:`Coords` is implemented as a subclass of :class:`numpy.ndarray`,
and thus inherits all its methods and atttributes.
The last axis of the :class:`Coords` however always has a length equal
to 3. Each set of 3 values along the last axis are the coordinates (in a
global 3D cartesian coordinate system) of a single point in space.
The full Coords array thus is a collection of points. It the array is
2-dimensional, the Coords is a flat list of points. But if the array
has more dimensions, the collection of points itself becomes structured.
The float datatype is only checked at creation time. It is the
responsibility of the user to keep this consistent
throughout the lifetime of the object.
Note
----
Methods that transform a Coords object, like
:meth:`scale`, :meth:`translate`, :meth:`rotate`, ...
do not change the original Coords object, but return a new object.
Some methods however have an `inplace` option that allows the user
to force coordinates to be changed in place. This option is seldom
used however: rather we conveniently use statements like::
X = X.some_transform()
and Python can immediately free and recollect the memory used for the old
object X.
Parameters
----------
data: float :term:`array_like`, or string
Data to initialize the Coords. The last axis should have a length
of 1, 2 or 3, but will be expanded to 3 if it is less, filling the
missing coordinates with zeros. Thus, if you only specify two
coordinates, all points are lying in the z=0 plane. Specifying only
one coordinate creates points along the x-axis.
As a convenience, data may also be entered as a string, which will be
passed to the :func:`pattern` function to create the actual
coordinates of the points.
If no data are provided, an empty Coords with shape (0,3) is created.
dtyp: float datatype, optional
It not provided, the datatype of ``data`` is used, or the default
:py:attr:`~arraytools.Float` (which is equivalent to
:data:`numpy.float32`).
copy: bool
If True, the data are copied. The default setting will try to use
the original data if possible, e.g. if `data` is a correctly shaped and
typed :class:`numpy.ndarray`.
Returns
-------
: Coords
An instance of the Coords class, which is basically an ndarray
of floats, with the last axis having a length of 3.
The Coords instance has a number of attributes that provide views on
(part of) the data. They are a notational convenience over using indexing.
These attributes can be used to set all or some of the coordinates
by direct assignment. The assigned data should however be broadcast
compatible with the assigned shape: the shape of the Coords can
not be changed.
Attributes
----------
xyz: float array
The full coordinate array as an ndarray.
x: float array
The X coordinates of the points as an ndarray with shape
:meth:`pshape()`.
y: float array
The Y coordinates of the points as an ndarray with shape
:meth:`pshape()`.
z: float array
The Z coordinates of the points as an ndarray with shape
:meth:`pshape()`.
xy: float array
The X and Y coordinates of the points as an ndarray with shape
:meth:`pshape()` + (2,).
xz: float array
The X and Z coordinates of the points as an ndarray with shape
:meth:`pshape()` + (2,).
yz: float array
The Y and Z coordinates of the points as an ndarray with shape
:meth:`pshape()` + (2,).
Examples
--------
>>> Coords([1.,2.])
Coords([ 1., 2., 0.])
>>> X = Coords(np.arange(6).reshape(2,3))
>>> print(X)
[[ 0. 1. 2.]
[ 3. 4. 5.]]
>>> print(X.y)
[ 1. 4.]
>>> X.z[1] = 9.
>>> print(X)
[[ 0. 1. 2.]
[ 3. 4. 9.]]
>>> print(X.xz)
[[ 0. 2.]
[ 3. 9.]]
>>> X.x = 0.
>>> print(X)
[[ 0. 1. 2.]
[ 0. 4. 9.]]
>>> Y = Coords(X) # Y shares its data with X
>>> Z = Coords(X, copy=True) # Z is independent
>>> Y.y = 5
>>> Z.z = 6
>>> print(X)
[[ 0. 5. 2.]
[ 0. 5. 9.]]
>>> print(Y)
[[ 0. 5. 2.]
[ 0. 5. 9.]]
>>> print(Z)
[[ 0. 1. 6.]
[ 0. 4. 6.]]
>>> X.coords is X
True
>>> Z.xyz = [1,2,3]
>>> print(Z)
[[ 1. 2. 3.]
[ 1. 2. 3.]]
>>> print(Coords('0123')) # initialize with string
[[ 0. 0. 0.]
[ 1. 0. 0.]
[ 1. 1. 0.]
[ 0. 1. 0.]]
"""
_exclude_members_ = ['actor']
#
# TODO
# Because the Coords class is sticky, results that are not conforming
# to the requirements of being a Coords array, should be converted to
# the general array class: e.g. return asarray(T)
#
# This could probably NOT be done in an __array_finalize__ method
# Maybe by oveloading __getitem__, but should we bother???
#
def __new__(clas, data=None, dtyp=at.Float, copy=False):
"""Create a new instance of :class:`Coords`."""
if data is None:
# create an empty array : we need at least a 2D array
# because we want the last axis to have length 3 and
# we also need an axis with length 0 to have size 0
ar = np.ndarray((0, 3), dtype=dtyp)
else:
# turn the data into an array, and copy if requested
# DO NOT ADD ndmin=1 HERE ! (see below)
if isinstance(data, str):
data = pattern(data, aslist=True)
ar = np.array(data, dtype=dtyp, copy=copy)
if ar.dtype.kind != 'f':
raise ValueError("data type should be of kind 'f'")
#
# The Coords object needs to be at least 1-D array, no a scalar
# We could force 'ar' above to be at least 1-D, but that would
# turn every scalar into a 1-D vector, which would circumvent
# detection of input errors (e.g. with translation, where input
# can be either a vector or an axis number)
#
if ar.ndim == 0:
raise ValueError("Expected array data, not a scalar")
if ar.shape[-1] == 3:
pass
elif ar.shape[-1] in [1, 2]:
# make last axis length 3, adding 0 values
ar = at.growAxis(ar, 3-ar.shape[-1], -1)
elif ar.shape[-1] == 0:
# allow empty coords objects
ar = ar.reshape(0, 3)
else:
raise ValueError("Expected a length 1,2 or 3 for last array axis")
# Make sure dtype is a float type
# This should not be needed in view of the above
assert (ar.dtype.kind == 'f')
# Transform 'subarr' from an ndarray to our new subclass.
ar = ar.view(clas)
return ar
@staticmethod
def __is_valid__(obj):
"""Check that an array is valid as Coords"""
return obj.shape[-1] == 3
# overload some some ndarray methods that could easily return
# invalid Coords
def __getitem__(self, i):
# this detects simple cases that should return ndarray
res = np.ndarray.__getitem__(self, i)
if res.ndim < 1 or res.shape[-1] != 3:
res = res.view(np.ndarray)
return res
[docs] def swapaxes(self, *args, **kargs):
res = np.ndarray.swapaxes(self, *args, **kargs)
if not Coords.__is_valid__(res):
res = res.view(np.ndarray)
return res
################ property methods ##########
@property
def xyz(self):
"""Returns the coordinates of the points as an ndarray.
Returns an ndarray with shape `self.shape` except last axis
is reduced to 2, providing a view on all the coordinates
of all the points.
"""
return self.view(type=np.ndarray)
@property
def x(self):
"""Returns the X-coordinates of all points.
Returns an ndarray with shape `self.pshape()`, providing a view
on the X-coordinates of all the points.
"""
return self.xyz[..., 0]
@property
def y(self):
"""Returns the Y-coordinates of all points.
Returns an ndarray with shape `self.pshape()`, providing a view
on the Y-coordinates of all the points.
"""
return self.xyz[..., 1]
@property
def z(self):
"""Returns the Z-coordinates of all points.
Returns an ndarray with shape `self.pshape()`, providing a view
on the Z-coordinates of all the points.
"""
return self[..., 2].view(type=np.ndarray)
@property
def xy(self):
"""Returns the X- and Y-coordinates of all points.
Returns an ndarray with shape `self.shape` except last axis
is reduced to 2, providing a view on the X- and Y-coordinates
of all the points.
"""
return self.xyz[..., :2]
@property
def xz(self):
"""Returns the X- and Y-coordinates of all points.
Returns an ndarray with shape `self.shape` except last axis
is reduced to 2, providing a view on the X- and Z-coordinates
of all the points.
"""
return self.xyz[..., (0, 2)]
@property
def yz(self):
"""Returns the X- and Y-coordinates of all points.
Returns an ndarray with shape `self.shape` except last axis
is reduced to 2, providing a view on the Y- and Z-coordinates
of all the points.
"""
return self.xyz[..., 1:]
################ property setters ##############
@xyz.setter
def xyz(self, value):
"""Set the XYZ coordinates of the points"""
self[...] = value
@x.setter
def x(self, value):
"""Set the X coordinates of the points"""
self[..., 0] = value
@y.setter
def y(self, value):
"""Set the Y coordinates of the points"""
self[..., 1] = value
@z.setter
def z(self, value):
"""Set the Z coordinates of the points"""
self[..., 2] = value
@xy.setter
def xy(self, value):
"""Set the XY coordinates of the points"""
self[..., :2] = value
@xz.setter
def xz(self, value):
"""Set the XZ coordinates of the points"""
self[..., (0, 2)] = value
@yz.setter
def yz(self, value):
"""Set the YZ coordinates of the points"""
self[..., 1:] = value
@property
def coords(self):
"""Returns the `Coords` object .
This exists only for consistency with other classes.
"""
return self
################ end property methods ##########
# def __repr__(self):
# """String representation of a Coords
# Examples
# --------
# >>> Coords([1.0,2.0,3.0])
# Coords([ 1., 2., 3.])
# """
# res = np.ndarray.__repr__(self)
# if self.dtype == at.Float:
# res = res.replace(', dtype=float32','')
# return res
[docs] def fprint(self, fmt="%10.3e %10.3e %10.3e"):
# TODO: this is a candidate for the library
# (possibly in a more general arrayprint form)
# (could be common with calpy)
"""Formatted printing of the points of a :class:`Coords` object.
Parameters
----------
fmt: string
Format to be used to print a single point.
The supplied format should contain exactly 3 formatting
sequences, ome for each of the three coordinates.
Examples
--------
>>> x = Coords([[[0.,0.],[1.,0.]],[[0.,1.],[0.,2.]]])
>>> x.fprint()
0.000e+00 0.000e+00 0.000e+00
1.000e+00 0.000e+00 0.000e+00
0.000e+00 1.000e+00 0.000e+00
0.000e+00 2.000e+00 0.000e+00
>>> x.fprint("%5.2f"*3)
0.00 0.00 0.00
1.00 0.00 0.00
0.00 1.00 0.00
0.00 2.00 0.00
"""
for p in self.points():
print(fmt % tuple(p))
#######################################################################
#
# Methods that return information about a Coords object or other
# views on the object data, without changing the object itself.
# General
[docs] def pshape(self):
"""Return the points shape of the :class:`Coords` object.
This is the shape of the :class:`numpy.ndarray` with the last axis
removed.
Note
----
The full shape of the Coords array can be obtained from
the inherited (NumPy) shape attribute.
Examples
--------
>>> X = Coords(np.arange(12).reshape(2,1,2,3))
>>> X.shape
(2, 1, 2, 3)
>>> X.pshape()
(2, 1, 2)
"""
return self.shape[:-1]
[docs] def points(self):
"""Return the :class:`Coords` object as a flat set of points.
Returns
-------
: Coords
The Coords reshaped to a 2-dimensional array, flattening
the structure of the points.
Examples
--------
>>> X = Coords(np.arange(12).reshape(2,1,2,3))
>>> X.shape
(2, 1, 2, 3)
>>> X.points().shape
(4, 3)
"""
return self.reshape((-1, 3))
[docs] def npoints(self):
"""Return the total number of points in the Coords.
Notes
-----
`npoints` and `ncoords` are equivalent. The latter exists to provide
a common interface with other geometry classes.
Examples
--------
>>> Coords(np.arange(12).reshape(2,1,2,3)).npoints()
4
"""
return np.array(self.shape[:-1]).prod()
ncoords = npoints
# Size, Bounds
[docs] def bbox(self):
"""Return the bounding box of a set of points.
The bounding box is the smallest rectangular volume in the global
coordinates, such that no points of the :class:`Coords` are outside
that volume.
Returns
-------
: Coords (2,3)
Coords array with two points: the first point contains the
minimal coordinates, the second has the maximal ones.
See Also
--------
center: return the center of the bounding box
bboxPoint: return a corner or middle point of the bounding box
bboxPoints: return all corners of the bounding box
Examples
--------
>>> X = Coords([[0.,0.,0.],[3.,0.,0.],[0.,3.,0.]])
>>> print(X.bbox())
[[ 0. 0. 0.]
[ 3. 3. 0.]]
"""
if self.size > 0:
x = self.points()
bb = np.row_stack([x.min(axis=0), x.max(axis=0)])
else:
o = origin()
bb = [o, o]
return Coords(bb)
[docs] def center(self):
"""Return the center of the :class:`Coords`.
The center of a Coords is the center of its bbox().
The return value is a (3,) shaped :class:`Coords` object.
See also
--------
bbox: return the bounding box of the Coords
centroid: return the average coordinates of the points
Examples
--------
>>> X = Coords([[0.,0.,0.],[3.,0.,0.],[0.,3.,0.]])
>>> print(X.center())
[ 1.5 1.5 0. ]
"""
X0, X1 = self.bbox()
return 0.5 * (X0+X1)
[docs] def bboxPoint(self, position):
"""Return a bounding box point of a Coords.
Bounding box points are points whose coordinates are either
the minimal value, the maximal value or the middle value
for the Coords.
Combining the three values in three dimensions results in
3**3 = 27 alignment points. The corner points of the
bounding box are a subset of these.
Parameters
----------
position: str
String of three characters, one for each direction 0, 1, 2.
Each character should be one of the following
- '-': use the minimal value for that coordinate,
- '+': use the minimal value for that coordinate,
- '0': use the middle value for that coordinate.
Any other character will set the corresponding coordinate to zero.
Notes
-----
A string '000' is equivalent with center(). The values '---' and
'+++' give the points of the bounding box.
See Also
--------
Coords.align: translate Coords by bboxPoint
Examples
--------
>>> X = Coords([[0.,0.,0.],[1.,1.,1.]])
>>> print(X.bboxPoint('-0+'))
[ 0. 0.5 1. ]
"""
bb = self.bbox()
al = {'-': bb[0], '+': bb[1], '0': 0.5*(bb[0]+bb[1])}
pt = np.zeros(3)
for i, c in enumerate(position):
if c in al:
pt[i] = al[c][i]
return Coords(pt)
[docs] def bboxPoints(self):
"""Return all the corners of the bounding box point of a Coords.
Returns
-------
: Coords (8,3)
A Coords with the eight corners of the bounding box, in the order
of a :py:attr:`elements.Hex8`.
See also
--------
bbox: return only two points, with the minimum and maximum coordinates
Examples
--------
>>> X = Coords([[0.,0.,0.],[3.,0.,0.],[0.,3.,0.]])
>>> print(X.bboxPoints())
[[ 0. 0. 0.]
[ 3. 0. 0.]
[ 3. 3. 0.]
[ 0. 3. 0.]
[ 0. 0. 0.]
[ 3. 0. 0.]
[ 3. 3. 0.]
[ 0. 3. 0.]]
"""
from pyformex.simple import cuboid
return cuboid(*self.bbox()).coords.reshape(-1, 3)
[docs] def average(self, wts=None, axis=None):
"""Returns a (weighted) average of the :class:`Coords`.
The average of a Coords is a Coords that is obtained by averaging
the points along some or all axes.
Weights can be specified to get a weighted average.
Parameters
----------
wts: float :term:`array_like`, optional
Weight to be attributed to the points. If provided, and `axis` is
an int, `wts` should be 1-dim with the same length as the
specified axis. Else, it has a shape equal to self.shape or
self.shape[:-1].
axis: int or tuple of ints, optional
If provided, the average is computed along the specified
axis/axes only. Else, the average is taken over all the points,
thus over all the axes of the array except the last.
Notes
-----
Averaging over the -1 axis does not make much sense.
Examples
--------
>>> X = Coords([[[0.,0.,0.],[1.,0.,0.],[2.,0.,0.]], \
[[4.,0.,0.],[5.,0.,0.],[6.,0.,0.]]])
>>> X = Coords(np.arange(6).reshape(3,2,1))
>>> X
Coords([[[ 0., 0., 0.],
[ 1., 0., 0.]],
<BLANKLINE>
[[ 2., 0., 0.],
[ 3., 0., 0.]],
<BLANKLINE>
[[ 4., 0., 0.],
[ 5., 0., 0.]]])
>>> print(X.average())
[ 2.5 0. 0. ]
>>> print(X.average(axis=0))
[[ 2. 0. 0.]
[ 3. 0. 0.]]
>>> print(X.average(axis=1))
[[ 0.5 0. 0. ]
[ 2.5 0. 0. ]
[ 4.5 0. 0. ]]
>>> print(X.average(wts=[0.5,0.25,0.25],axis=0))
[[ 1.5 0. 0. ]
[ 2.5 0. 0. ]]
>>> print(X.average(wts=[3,1],axis=1))
[[ 0.25 0. 0. ]
[ 2.25 0. 0. ]
[ 4.25 0. 0. ]]
>>> print(X.average(wts=at.multiplex([3,1],3,0)))
[ 2.25 0. 0. ]
"""
if axis is None:
axis = tuple(range(self.ndim-1))
if wts is not None:
wts = np.asarray(wts)
if wts.shape == self.shape:
pass
elif wts.shape == self.shape[:-1]:
wts = at.multiplex(wts, 3, -1)
else:
raise ValueError("Shape of wts should match "
"self.shape or self.pshape()")
return np.average(self, weights=wts, axis=axis)
[docs] def centroid(self):
"""Return the centroid of the :class:`Coords`.
The centroid of Coords is the point whose coordinates
are the mean values of all points.
Returns
-------
: Coords (3,)
A single point that is the centroid of the Coords.
See also
--------
center: return the center of the bounding box.
Examples
--------
>>> print(Coords([[0.,0.,0.],[3.,0.,0.],[0.,3.,0.]]).centroid())
[ 1. 1. 0.]
"""
return self.points().mean(axis=0)
[docs] def centroids(self):
"""Return the Coords itself.
Notes
-----
This method exists only to have a common interface with
other geometry classes.
"""
return self
[docs] def sizes(self):
"""Return the bounding box sizes of the :class:`Coords`.
Returns
-------
: array (3,)
The length of the bounding box along the three global axes.
See Also
--------
dsize: The diagonal size of the bounding box.
principalSizes: the sizes of the bounding box along the principal axes
Examples
--------
>>> print(Coords([[0.,0.,0.],[3.,0.,0.],[0.,3.,0.]]).sizes())
[ 3. 3. 0.]
"""
X0, X1 = self.bbox()
return X1-X0
[docs] def maxsize(self):
"""Return the maximum size of a Coords in any coordinate direction.
Returns
-------
: float
The maximum length of any edge of the bounding box.
Notes
-----
This is a convenient shorthand for `self.sizes().max()`.
See Also
--------
sizes: return the length of the bounding box along global axes
bbox: return the bounding box
Examples
--------
>>> print(Coords([[0.,0.,0.],[3.,0.,0.],[0.,3.,0.]]).maxsize())
3.0
"""
return self.sizes().max()
[docs] def dsize(self):
"""Return the diagonal size of the bounding box of the :class:`Coords`.
Returns
-------
: float
The length of the diagonal of the bounding box.
Notes
-----
All the points of the Coords are inside a sphere with the
:meth:`center` as center and the :meth:`dsize` as
length of the diameter (though it is not necessarily the
smallest bouding sphere).
:meth:`dsize` is in general a good estimate for the maximum size
of the cross section to be expected when the object can be rotated
freely around its center. It is conveniently used to zoom the
camera on an object, while guaranteeing that the full object
remains visible during rotations.
See Also
--------
bsphere: return radius of smallest sphere encompassing all points
sizes: return the length of the bounding box along global axes
bbox: return the bounding box
Examples
--------
>>> print(Coords([[0.,0.,0.],[3.,0.,0.],[0.,3.,0.]]).dsize())
4.24264
"""
X0, X1 = self.bbox()
return at.length(X1-X0)
[docs] def bsphere(self):
"""Return the radius of the bounding sphere of the :class:`Coords`.
The bounding sphere used here is the smallest sphere with center
in the center() of the :class:`Coords`, and such that no points of the
Coords are lying outside the sphere.
Returns
-------
: float
The maximum distance of any point to the `Coords.center`.
Notes
-----
This is not necessarily the absolute smallest bounding sphere,
because we use the center from lookin only in the global axes
directions.
Examples
--------
>>> X = Coords([[0.,0.,0.],[3.,0.,0.],[0.,3.,0.]])
>>> print(X.dsize(), X.bsphere())
4.24264 2.12132
>>> X = Coords([[0.5,0.],[1.,0.5],[0.5,1.0],[0.0,0.5]])
>>> print(X.dsize(), X.bsphere())
1.41421 0.5
"""
return self.distanceFromPoint(self.center()).max()
[docs] def bboxes(self):
"""Return the bboxes of all subsets of points in the Coords.
Subsets of points are 2-dim subarrays of the Coords, taken
along the two last axes. If the Coords has ndim==2, there
is only one subset: the full Coords.
Returns
-------
float array
Array with shape (...,2,3). The elements along the penultimate
axis are the minimal and maximal values of the Coords
along that axis.
Examples
--------
>>> X = Coords(np.arange(18).reshape(2,3,3))
>>> print(X)
[[[ 0. 1. 2.]
[ 3. 4. 5.]
[ 6. 7. 8.]]
<BLANKLINE>
[[ 9. 10. 11.]
[ 12. 13. 14.]
[ 15. 16. 17.]]]
>>> print(X.bboxes())
[[[ 0. 1. 2.]
[ 6. 7. 8.]]
<BLANKLINE>
[[ 9. 10. 11.]
[ 15. 16. 17.]]]
"""
return at.minmax(self, axis=1)
# Inertia
[docs] @utils.warning("warn_inertia_changed")
def inertia(self, mass=None):
"""Return inertia related quantities of the :class:`Coords`.
Parameters
----------
mass: float array, optional
If provided, it is a 1-dim array with :meth:`npoints` weight
values for the points, in the order of the :meth:`points`.
The default is to attribute a weight 1.0 to each point.
Returns
-------
:class:`~inertia.Inertia`
The Inertia object has the following attributes:
- ``mass``: the total mass (float)
- ``ctr``: the center of mass: float (3,)
- ``tensor``: the inertia tensor in the central axes: shape (3,3)
See Also
--------
principalCS: Return the principal axes of the inertia tensor
Examples
--------
>>> from pyformex.elements import Tet4
>>> I = Tet4.vertices.inertia()
>>> print(I.tensor)
[[ 1.5 0.25 0.25]
[ 0.25 1.5 0.25]
[ 0.25 0.25 1.5 ]]
>>> print(I.ctr)
[ 0.25 0.25 0.25]
>>> print(I.mass)
4.0
"""
from pyformex import inertia
M, C, I = inertia.point_inertia(self.points(), mass) # noqa: E741
I = inertia.Tensor(I) # noqa: E741
return inertia.Inertia(I, ctr=C, mass=M)
[docs] def principalCS(self, mass=None):
"""Return a CoordSys formed by the principal axes of inertia.
Parameters
----------
mass: 1-dim float array (:meth:`points`,), optional
The mass to be attributed to each of the points, in the order
of :meth:`npoints`. If not provided, a mass 1.0 will be
attributed to each point.
Returns
-------
:class:`~coordsys.CoordSys` object.
Coordinate system aligned along the principal axes of the inertia,
for the specified point masses. The origin of the CoordSys is
the center of mass of the Coords.
See Also
--------
centralCS: CoordSys at the center of mass, but axes along global
directions
Examples
--------
>>> from pyformex.elements import Tet4
>>> print(Tet4.vertices.principalCS())
CoordSys: trl=[ 0.25 0.25 0.25]; rot=[[ 0.58 0.58 0.58]
[ 0.34 -0.81 0.47]
[ 0.82 -0.41 -0.41]]
"""
from pyformex.coordsys import CoordSys
I = self.inertia(mass) # noqa: E741
prin, axes = I.principal()
return CoordSys(rot=axes, trl=I.ctr)
[docs] def principalSizes(self):
"""Return the sizes in the principal directions of the :class:`Coords`.
Returns
-------
float array (3,)
Array with the size of the bounding box along the 3
principal axes.
Notes
-----
This is a convenient shorthand for:
``self.toCS(self.principalCS()).sizes()``
Examples
--------
>>> print(Coords([[[0.,0.,0.],[3.,0.,0.]]]).rotate(30,2).principalSizes())
[ 0. 0. 3.]
"""
return self.toCS(self.principalCS()).sizes()
[docs] def centralCS(self, mass=None):
"""Returns the central coordinate system of the Coords.
Parameters
----------
mass: 1-dim float array (:meth:`points`,), optional
The mass to be attributed to each of the points, in the order
of :meth:`npoints`. If not provided, a mass 1.0 will be
attributed to each point.
Returns
-------
:class:`~coordsys.CoordSys` object.
Coordinate system with origin at the center of mass of the
Coords and axes parallel to the global axes.
See Also
--------
principalCS: CoordSys aligned with principa axes of inertia tensor
Examples
--------
>>> from pyformex.elements import Tet4
>>> print(Tet4.vertices.centralCS())
CoordSys: trl=[ 0.25 0.25 0.25]; rot=[[ 1. 0. 0.]
[ 0. 1. 0.]
[ 0. 0. 1.]]
"""
from pyformex.coordsys import CoordSys
C = self.reshape(-1, 3).average(wts=mass, axis=0)
return CoordSys(trl=C)
# Distance
[docs] def distanceFromPoint(self, p):
"""Returns the distance of all points from the point p.
Parameters
----------
p: float :term:`array_like` with shape (3,) or (1,3)
Coordinates of a single point in space
Returns
-------
float array
Array with shape :meth:`pshape` holding the distance of
each point to point p. All values are positive or zero.
See Also
--------
closestPoint: return the point of Coords closest to given point
Examples
--------
>>> X = Coords([[0.,0.,0.],[2.,0.,0.],[1.,3.,0.],[-1.,0.,0.]])
>>> print(X.distanceFromPoint([0.,0.,0.]))
[ 0. 2. 3.16 1. ]
"""
p = at.checkArray(p, size=3, kind='f', allow='i').reshape(3)
return at.length(self-p)
[docs] def distanceFromLine(self, p, n):
"""Returns the distance of all points from the line (p,n).
Parameters
----------
p: float :term:`array_like` with shape (3,) or (1,3)
Coordinates of some point on the line.
n: float :term:`array_like` with shape (3,) or (1,3)
Vector specifying the direction of the line.
Returns
-------
float array
Array with shape :meth:`pshape` holding the distance
of each point to the line through p and having direction n.
All values are positive or zero.
Examples
--------
>>> X = Coords([[0.,0.,0.],[2.,0.,0.],[1.,3.,0.],[-1.,0.,0.]])
>>> print(X.distanceFromLine([0.,0.,0.],[1.,1.,0.]))
[ 0. 1.41 1.41 0.71]
"""
p = at.checkArray(p, size=3, kind='f', allow='i').reshape(3)
n = at.checkArray(n, size=3, kind='f', allow='i').reshape(3)
n = at.normalize(n)
xp = self-p
xpt = at.dotpr(xp, n)
a = at.dotpr(xp, xp)-xpt*xpt
return np.sqrt(a.clip(0))
[docs] def distanceFromPlane(self, p, n):
"""Return the distance of all points from the plane (p,n).
Parameters
----------
p: float :term:`array_like` with shape (3,) or (1,3)
Coordinates of some point in the plane.
n: float :term:`array_like` with shape (3,) or (1,3)
The normal vector to the plane.
Returns
-------
float array
Array with shape :meth:`pshape` holding the distance
of each point to the plane through p and having normal n.
The values are positive if the point is on the side of the
plane indicated by the positive normal.
See Also
--------
directionalSize: find the most distant points at both sides of plane
Examples
--------
>>> X = Coords([[0.,0.,0.],[2.,0.,0.],[1.,3.,0.],[-1.,0.,0.]])
>>> print(X.distanceFromPlane([0.,0.,0.],[1.,0.,0.]))
[ 0. 2. 1. -1.]
"""
p = at.checkArray(p, size=3, kind='f', allow='i').reshape(3)
n = at.checkArray(n, size=3, kind='f', allow='i').reshape(3)
n = at.normalize(n)
d = np.inner(self, n) - np.inner(p, n)
return np.asarray(d)
[docs] def closestToPoint(self, p, return_dist=False):
"""Returns the point closest to a given point p.
Parameters
----------
p: :term:`array_like` (3,)
Coordinates of a single point in space
Returns
-------
:int
Index of the point in the Coords that has the
minimal Euclidean distance to the point `p`.
Use this index with self.points() to get the
coordinates of that point.
Examples
--------
>>> X = Coords([[[0.,0.,0.],[3.,0.,0.],[0.,3.,0.]]])
>>> X.closestToPoint([2.,0.,0.])
1
>>> X.closestToPoint([2.,0.,0.],True)
(1, 1.0)
"""
d = self.distanceFromPoint(p)
i = d.argmin()
if return_dist:
return i, d.flat[i]
else:
return i
[docs] def directionalSize(self, n, p=None, return_points=False):
"""Returns the extreme distances from the plane p,n.
Parameters
----------
n: a single int or a float :term:`array_like` (3,)
The direction of the normal to the plane. If an int, it is the
number of a global axis. Else it is a vector with 3 components.
p: :term:`array_like` (3,), optional
Coordinates of a point in the plane. If not provided,
the :meth:`center` of the Coords is used.
return_points: bool
If True, also return a Coords with two points along the line
(p,n) and at the extreme distances from the plane(p,n).
Returns
-------
dmin: float
The minimal (signed) distance of a point of the Coords to the
plane (p,n). The value can be negative or positive.
dmax: float
The maximal (signed) distance of a point of the Coords to the
plane (p,n). The value can be negative or positive.
points: Coords (2,3), optional
If `return_points=True` is provided, also returns a Coords
holding two points on the line (p,n) with minimal and
maximal distance from the plane (p,n). These two points
together with the normal `n` define two parallel planes
such that all points of `self` are between or on the planes.
Notes
-----
The maximal size of `self` in the direction `n` is found from
the difference `dmax` - dmin`. See also :meth:`directionalWidth`.
See also
--------
directionalExtremes: return two points in the extreme planes
directionalWidth: return the distance between the extreme planes
distanceFromPlane: return distance of all points to a plane
Examples
--------
>>> X = Coords([[[0.,0.,0.],[3.,0.,0.],[0.,3.,0.]]])
>>> X.directionalSize([1,0,0])
(-1.5, 1.5)
>>> X.directionalSize([1,0,0],[1.,0.,0.])
(-1.0, 2.0)
>>> X.directionalSize([1,0,0],return_points=True)
(-1.5, 1.5, Coords([[ 0. , 1.5, 0. ],
[ 3. , 1.5, 0. ]]))
"""
n = at.unitVector(n)
if p is None:
p = self.center()
else:
p = Coords(p)
d = self.distanceFromPlane(p, n)
dmin, dmax = d.min(), d.max()
if return_points:
return dmin, dmax, Coords([p+dmin*n, p+dmax*n])
else:
return dmin, dmax
[docs] def directionalExtremes(self, n, p=None):
"""Returns extremal planes in the direction n.
Parameters: see :meth:`directionalSize`.
Returns
-------
:Coords (2,3)
A Coords holding the two points on the line (p,n) with minimal
and maximal distance from the plane (p,n). These two points
together with the normal `n` define two parallel planes
such that all points of `self` are between or on the planes.
See also
--------
directionalSize: return minimal and maximal distance from plane
Notes
-----
This is like directionalSize with the return_points options,
but only returns the extreme points.
Examples
--------
>>> X = Coords([[[0.,0.,0.],[3.,0.,0.],[0.,3.,0.]]])
>>> X.directionalExtremes([1,0,0])
Coords([[ 0. , 1.5, 0. ],
[ 3. , 1.5, 0. ]])
"""
return self.directionalSize(n, p, return_points=True)[2]
[docs] def directionalWidth(self, n):
"""Returns the width of a Coords in the given direction.
Parameters: see :meth:`directionalSize`.
Returns
-------
:float
The size of the Coords in the direction `n`. This is the
distance between the extreme planes with normal `n` touching
the Coords.
See also
--------
directionalSize: return minimal and maximal distance from plane
Notes
-----
This is like directionalSize but only returns the difference between
`dmax` and `dmin`.
Examples
--------
>>> X = Coords([[[0.,0.,0.],[3.,0.,0.],[0.,3.,0.]]])
>>> print(X.directionalWidth([1,0,0]))
3.0
"""
dmin, dmax = self.directionalSize(n)
return dmax-dmin
# Test position
[docs] def test(self, dir=0, min=None, max=None, atol=0.):
"""Flag points having coordinates between min and max.
Test the position of the points of the :class:`Coords` with respect to
one or two parallel planes. This method is very convenient in clipping
a Coords in a specified direction. In most cases the clipping
direction is one of the global coordinate axes, but a general
direction may be used as well.
Testing along global axis directions is highly efficient. It tests
whether the corresponding coordinate is above or equal to the `min`
value and/or below or equal to the `max` value. Testing in a general
direction tests whether the distance to the `min` plane is positive
or zero and/or the distance to the `max` plane is negative or zero.
Parameters
----------
dir: a single int or a float :term:`array_like` (3,)
The direction in which to measure distances. If an int, it is
one of the global axes (0,1,2). Else it is a vector with 3
components. The default direction is the global x-axis.
min: float or point-like, optional
Position of the minimal clipping plane.
If `dir` is an int, this is a single float giving the coordinate
along the specified global axis. If `dir` is a vector, this must
be a point and the minimal clipping plane is defined by this point
and the normal vector `dir`. If not provided, there is no clipping
at the minimal side.
max: float or point-like.
Position of the maximal clipping plane.
If `dir` is an int, this is a single float giving the coordinate
along the specified global axis. If `dir` is a vector, this must
be a point and the maximal clipping plane is defined by this point
and the normal vector `dir`. If not provided, there is no clipping
at the maximal side.
atol: float
Tolerance value added to the tests to account for accuracy
and rounding errors.
A `min` test will be ok if the point's distance from the
`min` clipping plane is `> -atol` and/or the distance from the
`max` clipping plane is `< atol`. Thus a positive atol widens the
clipping planes.
Returns
-------
: bool array with shape :meth:`pshape`
Array flagging whether the points for the Coords pass the test(s)
or not. The return value can directly be used as an index to
`self` to obtain a :class:`Coords` with the points satisfying
the test (or not).
Raises
------
ValueError: At least one of min or max have to be specified
If neither `min` nor `max` are provided.
Examples
--------
>>> x = Coords([[[0.,0.],[1.,0.]],[[0.,1.],[0.,2.]]])
>>> print(x.test(min=0.5))
[[False True]
[False False]]
>>> t = x.test(dir=1,min=0.5,max=1.5)
>>> print(x[t])
[[ 0. 1. 0.]]
>>> print(x[~t])
[[ 0. 0. 0.]
[ 1. 0. 0.]
[ 0. 2. 0.]]
"""
if min is None and max is None:
raise ValueError("At least one of min or max have to be specified.")
if np.array(dir).size == 1:
if min is not None:
T1 = self[..., dir] >= (min - atol)
if max is not None:
T2 = self[..., dir] <= (max + atol)
else:
if min is not None:
T1 = self.distanceFromPlane(min, dir) > - atol
if max is not None:
T2 = self.distanceFromPlane(max, dir) < atol
if min is None:
T = T2
elif max is None:
T = T1
else:
T = T1 * T2
return np.asarray(T)
########################################################################
[docs] def set(self, f):
"""Set the coordinates from those in the given array.
Parameters
----------
f: float :term:`array_like`, broadcastable to self.shape.
The coordinates to replace the current ones. This can not
be used to chage the shape of the Coords.
Raises
------
ValueError:
If the shape of `f` does not allow broadcasting to `self.shape`.
Examples
--------
>>> x = Coords([[0],[1],[2]])
>>> print(x)
[[ 0. 0. 0.]
[ 1. 0. 0.]
[ 2. 0. 0.]]
>>> x.set([0.,1.,0.])
>>> print(x)
[[ 0. 1. 0.]
[ 0. 1. 0.]
[ 0. 1. 0.]]
"""
f = at.checkArray(f, kind='f', allow='i')
if at.checkBroadcast(self.shape, f.shape) != self.shape:
raise ValueError("Invalid array shape")
self[...] = f # do not be tempted to use self = f !
##############################################################################
#
# Transformations that preserve the topology (but change coordinates)
#
# A. Affine transformations
#
# Scaling
# Translation
# Central Dilatation = Scaling + Translation
# Rotation
# Shear
# Reflection
# Affine
#
# The following methods return transformed coordinates, but by default
# they do not change the original data. If the optional argument inplace
# is set True, however, the coordinates are changed inplace.
[docs] def scale(self, scale, dir=None, center=None, inplace=False):
"""Return a scaled copy of the :class:`Coords` object.
Parameters
----------
scale: float or tuple of 3 floats
Scaling factor(s). If it is a single value, and no `dir` is
provided, scaling is uniformly applied to all axes; if `dir`
is provided, only to the specified directions. If it is a tuple,
the three scaling factors are applied to the respective
global axes.
dir: int or tuple of ints, optional
One or more global axis numbers (0,1,2), indicating the direction(s)
that should be scaled with the (single) value `scale`.
center: point-like, optional
If provided, use this point as the center of the scaling.
The default is the global origin.
inplace: bool,optional
If True, the coordinates are change in-place.
Returns
-------
: Coords
The Coords scaled as specified.
Notes
-----
If a `center` is provided,the operation is equivalent with
``self.translate(-center).scale(scale,dir).translate(center)``
Examples
--------
>>> X = Coords([1.,1.,1.])
>>> print(X.scale(2))
[ 2. 2. 2.]
>>> print(X.scale([2,3,4]))
[ 2. 3. 4.]
>>> print(X.scale(2,dir=(1,2)).scale(4,dir=0))
[ 4. 2. 2.]
>>> print(X.scale(2,center=[1.,0.5,0.]))
[ 1. 1.5 2. ]
"""
if center is not None:
center = np.asarray(center)
return self.trl(-center).scale(scale, dir).translate(center)
if inplace:
out = self
else:
out = self.copy()
if dir is None:
out *= scale
else:
out[..., dir] *= scale
return out
[docs] def translate(self, dir, step=1.0, inplace=False):
"""Return a translated copy of the :class:`Coords` object.
Translate the Coords in the direction `dir` over a distance
`step * at.length(dir)`.
Parameters
----------
dir: int (0,1,2) or float :term:`array_like` (...,3)
The translation vector. If an int, it specifies a global axis
and the translation is in the direction of that axis.
If an :term:`array_like`, it specifies one or more translation vectors.
If more than one, the array should be broadcastable to the Coords
shape: this allows to translate different parts of the Coords over
different vectors, all in one operation.
step: float
If ``dir`` is an int, this is the length of the translation.
Else, it is a multiplying factor applied to ``dir`` prior to
applying the translation.
Returns
-------
: Coords
The Coords translated over the specified vector(s).
Note
----
:meth:`trl` is a convenient shorthand for :meth:`translate`.
See Also
--------
centered: translate to center around origin
Coords.align: translate to align bounding box
Examples
--------
>>> x = Coords([1.,1.,1.])
>>> print(x.translate(1))
[ 1. 2. 1.]
>>> print(x.translate(1,1.))
[ 1. 2. 1.]
>>> print(x.translate([0,1,0]))
[ 1. 2. 1.]
>>> print(x.translate([0,2,0],0.5))
[ 1. 2. 1.]
>>> x = Coords(np.arange(4).reshape(2,2,1))
>>> x
Coords([[[ 0., 0., 0.],
[ 1., 0., 0.]],
<BLANKLINE>
[[ 2., 0., 0.],
[ 3., 0., 0.]]])
>>> x.translate([[10.,-5.,0.],[20.,4.,0.]]) # translate with broadcasting
Coords([[[ 10., -5., 0.],
[ 21., 4., 0.]],
<BLANKLINE>
[[ 12., -5., 0.],
[ 23., 4., 0.]]])
"""
if inplace:
out = self
else:
out = self.copy()
if at.isInt(dir):
out[..., dir] += step
else:
dir = Coords(dir, copy=True)
if step != 1.:
dir *= step
out += dir
return out
[docs] def centered(self):
"""Return a centered copy of the Coords.
Returns
-------
: Coords
The Coords translated over tus that its :meth:`center`
coincides with the origin of the global axes.
Notes
-----
This is equivalent with ``self.translate(-self.center())``
Examples
--------
>>> X = Coords('0123')
>>> print(X)
[[ 0. 0. 0.]
[ 1. 0. 0.]
[ 1. 1. 0.]
[ 0. 1. 0.]]
>>> print(X.centered())
[[-0.5 -0.5 0. ]
[ 0.5 -0.5 0. ]
[ 0.5 0.5 0. ]
[-0.5 0.5 0. ]]
"""
return self.translate(-self.center())
[docs] def align(self, alignment='---', point=[0., 0., 0.]):
"""Align a :class:`Coords` object on a given point.
Alignment involves a translation such that the bounding box
of the Coords object becomes aligned with a given point.
The bounding box alignment is done by the translation of a
to the target point.
Parameters
----------
alignment: str
The requested alignment is a string of three characters,
one for each of the coordinate axes. The character determines how
the structure is aligned in the corresponding direction:
- '-': aligned on the minimal value of the bounding box,
- '+': aligned on the maximal value of the bounding box,
- '0': aligned on the middle value of the bounding box.
Any other value will make the alignment in that direction unchanged.
point: point-like
The target point of the alignment.
Returns
-------
: Coords
The Coords translated thus that the `alignment`
:meth:`bboxPoint` is at `point`.
Notes
-----
The default parameters translate the Coords thus that all points
are in the octant with all positive coordinate values.
``Coords.align(alignment = '000')`` will center the object around
the origin, just like the :meth:`centered` (which is slightly faster).
This can however be used for centering around any point.
See also
--------
align: aligning multiple objects with respect to each other.
"""
return self.translate(point-self.bboxPoint(alignment))
[docs] def rotate(self, angle, axis=2, around=None, angle_spec=at.DEG):
"""Return a copy rotated over angle around axis.
Parameters
----------
angle: float or float :term:`array_like` (3,3)
If a float, it is the rotation angle, by default in degrees,
and the parameters (angle, axis, angel_spec) are passed to
:func:`~arraytools.rotationMatrix` to produce a (3,3) rotation
matrix.
Alternatively, the rotation matrix may be directly provided
in the `angle` parameter. The `axis` and `angle_spec` are then
ignored.
axis: int (0,1,2) or float :term:`array_like` (3,)
Only used if `angle` is a float.
If provided, it specifies the direction of the rotation axis:
either one of 0,1,2 for a global axis, or a vector with
3 components for a general direction. The default (axis 2)
is convenient for working with 2D-structures in the x-y plane.
around: float :term:`array_like` (3,)
If provided, it specifies a point on the rotation axis. If not,
the rotation axis goes through the origin of the global axes.
angle_spec: float, at.DEG or RAD, optional
Only used if `angle` is a float.
The default (at.DEG) interpretes the angle in degrees. Use RAD to
specify the angle in radians.
Returns
-------
Coords
The Coords rotated as specified by the parameters.
Note
----
:meth:`rot` is a convenient shorthand for :meth:`rotate`.
See Also
--------
translate: translate a Coords
affine: rotate and translate a Coords
arraytools.rotationMatrix:
create a rotation matrix for use in :meth:`rotate`
Examples
--------
>>> X = Coords('0123')
>>> print(X.rotate(30))
[[ 0. 0. 0. ]
[ 0.87 0.5 0. ]
[ 0.37 1.37 0. ]
[-0.5 0.87 0. ]]
>>> print(X.rotate(30,axis=0))
[[ 0. 0. 0. ]
[ 1. 0. 0. ]
[ 1. 0.87 0.5 ]
[ 0. 0.87 0.5 ]]
>>> print(X.rotate(30,axis=0,around=[0.,0.5,0.]))
[[ 0. 0.07 -0.25]
[ 1. 0.07 -0.25]
[ 1. 0.93 0.25]
[ 0. 0.93 0.25]]
>>> m = at.rotationMatrix(30,axis=0)
>>> print(X.rotate(m))
[[ 0. 0. 0. ]
[ 1. 0. 0. ]
[ 1. 0.87 0.5 ]
[ 0. 0.87 0.5 ]]
"""
mat = np.asarray(angle)
if mat.size == 1:
mat = at.rotationMatrix(angle, axis=axis, angle_spec=angle_spec)
mat = at.checkArray(mat, shape=(3, 3), kind='f')
if around is not None:
around = np.asarray(around)
out = self.translate(-around)
else:
out = self
return out.affine(mat, around)
[docs] def shear(self, dir, dir1, skew, inplace=False):
"""Return a copy skewed in the direction of a global axis.
This translates points in the direction of a global axis,
over a distance dependent on the coordinates along another axis.
Parameters
----------
dir: int (0,1,2)
Global axis in which direction the points are translated.
dir1: int (0,1,2)
Global axis whose coordinates determine the length of the
translation.
skew: float
Multiplication factor to the coordinates dir1 defining the
translation distance.
inplace: bool, optional
If True, the coordinates are translated in-place.
Notes
-----
This replaces the coordinate ``dir`` with ``(dir + skew * dir1)``.
If dir and dir1 are different, rectangular shapes in the plane
(dir,dir1) are thus skewed along the direction dir into
parallellogram shapes. If dir and dir1 are the same direction, the
effect is that of scaling in the dir direction.
Examples
--------
>>> X = Coords('0123')
>>> print(X.shear(0,1,0.5))
[[ 0. 0. 0. ]
[ 1. 0. 0. ]
[ 1.5 1. 0. ]
[ 0.5 1. 0. ]]
"""
if inplace:
out = self
else:
out = self.copy()
out[..., dir] += skew * out[..., dir1]
return out
[docs] def reflect(self, dir=0, pos=0., inplace=False):
# TODO: Add mirroring against any plane/axis/point
"""Reflect the coordinates in the direction of a global axis.
Parameters
----------
dir: int (0,1,2)
Global axis direction of the reflection (default 0 or x-axis).
pos: float
Offset of the mirror plane from origin (default 0.0)
inplace: bool, optional
If True, the coordinates are translated in-place.
Returns
-------
:Coords
A mirror copy with respect to the plane perpendicular to axis `dir`
and placed at coordinate `pos` along the `dir` axis.
Examples
--------
>>> X = Coords('012')
>>> print(X)
[[ 0. 0. 0.]
[ 1. 0. 0.]
[ 1. 1. 0.]]
>>> print(X.reflect(0))
[[ 0. 0. 0.]
[-1. 0. 0.]
[-1. 1. 0.]]
>>> print(X.reflect(1,0.5))
[[ 0. 1. 0.]
[ 1. 1. 0.]
[ 1. 0. 0.]]
>>> print(X.reflect([0,1],[0.5,0.]))
[[ 1. 0. 0.]
[ 0. 0. 0.]
[ 0. -1. 0.]]
"""
if inplace:
out = self
else:
out = self.copy()
out[..., dir] = 2*np.asarray(pos) - out[..., dir]
return out
[docs] def affine(self, mat, vec=None):
"""Perform a general affine transformation.
Parameters
----------
mat: float :term:`array_like` (3,3)
Matrix used in post-multiplication on a row vector to produce
a new vector. The matrix can express scaling and/or rotation
or a more general (affine) transformation.
vec: float :term:`array_like` (3,)
Translation vector to add after the transformation with `mat`.
Returns
-------
: Coords
A Coords with same shape as self, but with coordinates given by
``self * mat + vec``. If `mat` is a rotation matrix or a uniform
scaling plus rotation, the full operation performs a rigid rotation
plus translation of the object.
Examples
--------
>>> X = Coords('0123')
>>> S = np.array([[2.,0.,0.],[0.,3.,0.],[0.,0.,4.]]) # non-uniform scaling
>>> R = at.rotationMatrix(90.,2) # rotation matrix
>>> T = [20., 0., 2.] # translation
>>> M = np.dot(S,R) # combined scaling and rotation
>>> print(X.affine(M,T))
[[ 20. 0. 2.]
[ 20. 2. 2.]
[ 17. 2. 2.]
[ 17. 0. 2.]]
"""
out = np.dot(self, mat)
if vec is not None:
out += vec
return out
[docs] def toCS(self, cs):
"""Transform the coordinates to another CoordSys.
Parameters
----------
cs: :class:`~coordsys.CoordSys` object
Cartesian coordinate system in which to take the coordinates of
the current Coords object.
Returns
-------
Coords
A Coords object identical to self but having global coordinates
equal to the coordinates of self in the `cs` CoordSys axes.
Note
----
This returns the coordinates of the original points in another
CoordSys. If you use these coordinates as points in the global axes,
the transformation of the original points to these new ones is the
inverse transformation of the transformation of the global axes
to the `cs` coordinate system.
See Also
--------
fromCS: the inverse transformation
Examples
--------
>>> X = Coords('01')
>>> print(X)
[[ 0. 0. 0.]
[ 1. 0. 0.]]
>>> from pyformex.coordsys import CoordSys
>>> CS = CoordSys(oab=[[0.5,0.,0.],[1.,0.5,0.],[0.,1.,0.]])
>>> print(CS)
CoordSys: trl=[ 0.5 0. 0. ]; rot=[[ 0.71 0.71 0. ]
[-0.71 0.71 0. ]
[ 0. -0. 1. ]]
>>> print(X.toCS(CS))
[[-0.35 0.35 0. ]
[ 0.35 -0.35 0. ]]
>>> print(X.toCS(CS).fromCS(CS))
[[ 0. 0. 0.]
[ 1. -0. 0.]]
"""
return self.trl(-cs.trl).rot(cs.rot.transpose())
[docs] def fromCS(self, cs):
"""Transform the coordinates from another CoordSys to global axes.
Parameters
----------
cs: :class:`~coordsys.CoordSys` object
Cartesian coordinate system in which the current coordinate
values are taken.
Returns
-------
Coords
A Coords object with the global coordinates of the same points
as the input coordinates represented in the `cs` CoordSys axes.
See Also
--------
toCS: the inverse transformation
Examples: see :meth:`toCS`
"""
return self.rot(cs.rot).trl(cs.trl)
[docs] def transformCS(self, cs, cs0=None):
"""Perform a coordinate system transformation on the Coords.
This method transforms the Coords object by the transformation that
turns one coordinate system into a another.
Parameters
----------
cs: :class:`~coordsys.CoordSys`
The final coordinate system.
cs0: :class:`~coordsys.CoordSys`, optional
The initial coordinate system. If not provided, the global
coordinate system is used.
Returns
-------
Coords
The input Coords transformed by the same affine transformation
that turns the axes of the coordinate system `cs0`
into those of the system `cs`.
Notes
-----
For example, with the default `cs0` and a `cs` CoordSys created with
the points ::
0. 1. 0.
-1. 0. 0.
0. 0. 1.
0. 0. 0.
the transformCS results in a rotation of 90 degrees around the z-axis.
See Also
--------
toCS: transform coordinates to another CS
fromCS: transfrom coordinates from another CS
"""
if cs0 is not None:
f = self.toCS(cs0)
else:
f = self
return f.fromCS(cs)
[docs] def position(self, x, y):
"""Position a :class:`Coords` so that 3 points x are aligned with y.
Aligning 3 points x with 3 points y is done by a rotation and
translation in such way that
- point x0 coincides with point y0,
- line x0,x1 coincides with line y0,y1
- plane x0,x1,x2 coincides with plane y0,y1,y2
Parameters
----------
x: float :term:`array_like` (3,3)
Original coordinates of three non-collinear points. These points
can be be part of the Coords or not.
y: float :term:`array_like` (3,3)
Final coordinates of the three points.
Returns
-------
Coords
The input Coords rotated and translated thus that the points
x are aligned with y.
Notes
-----
This is a convenient shorthand for ``self.affine(*trfmat(x, y))``.
See Also
--------
arraytools.trfmat: compute the transformation matrices from points x to y
affine: general transform using rotation and translation
Examples
--------
>>> X = Coords([[0,0,0],[1,0,0],[1,1,0]])
>>> Y = Coords([[1,1,1],[1,10,1],[1,1,100]])
>>> print(X.position(X,Y))
[[ 1. 1. 1.]
[ 1. 2. 1.]
[ 1. 2. 2.]]
"""
return self.affine(*at.trfmat(x, y))
#
#
# B. Non-Affine transformations.
#
# These always return copies !
#
# Cylindrical, Spherical, Isoparametric
#
[docs] def cylindrical(self, dir=(0, 1, 2), scale=(1., 1., 1.), angle_spec=at.DEG):
"""Convert from cylindrical coordinates to cartesian.
A cylindrical coordinate system is defined by a longitudinal axis
axis (z) and a radial axis (r). The cylindrical coordinates of
a point are:
- r: the radial distance from the z-axis,
- theta: the circumferential angle measured positively around
the z-axis starting from zero at the (r-z) halfplane,
- z: the axial distance along the z-axis,
This function interpretes the 3 coordinates of the points
as (r,theta,z) values and computes the corresponding global
cartesian coordinates (x,y,z).
Parameters
----------
dir: tuple of 3 ints, optional
If provided, it is a permutation of (0,1,2) and specifies
which of the current coordinates are interpreted as resp.
distance(r), angle(theta) and height(z).
Default order is (r,theta,z).
Beware that if the permutation is not conserving the order
of the axes, a left-handed system results, and the Coords will
appear mirrored in the right-handed systems exclusively used
by pyFormex
scale: tuple of 3 floats, optional
Scaling factors that are applied on the values prior to make the
conversion from cylindrical to cartesian coordinates. These factors
are always given in the order (r,theta,z), irrespective of the
permutation by `dir`.
angle_spec: float, at.DEG or RAD, optional
Multiplication factor for angle coordinates.
The default (at.DEG) interpretes the angle in degrees. Use RAD to
specify the angle in radians.
Returns
-------
Coords
The global coordinates of the points that were specified with
cylindrical coordinates as input.
Notes
-----
The scaling can also be applied independently prior to transforming.
``X.cylindrical(scale=s)`` is equivalent with
``X.scale(s).cylindrical()``. The scale option is provided here
because in many cases you need at least to scale the theta direction
to have proper angle values.
See Also
--------
hyperCylindrical: similar but allowing scaling as function of angle
toCylindrical: inverse transformation (cartesian to cylindrical)
Examples
--------
We want to create six points on a circle with radius 2. We start
by creating the points in cylindrical coordinates with unit distances.
>>> X = Coords('1'+'2'*5)
>>> print(X)
[[ 1. 0. 0.]
[ 1. 1. 0.]
[ 1. 2. 0.]
[ 1. 3. 0.]
[ 1. 4. 0.]
[ 1. 5. 0.]]
Remember these are (r,theta,z) coordinates of the points. So we
will scale the r-direction with 2 (the target radius) and the
angular direction theta with 360/6 = 60.
Then we get the cartesian coordinates of the points from
>>> Y = X.cylindrical(scale=(2.,60.,1.))
>>> print(Y)
[[ 2. 0. 0. ]
[ 1. 1.73 0. ]
[-1. 1.73 0. ]
[-2. -0. 0. ]
[-1. -1.73 0. ]
[ 1. -1.73 0. ]]
Going back to cylindrical coordinates yields
>>> print(Y.toCylindrical())
[[ 2. 0. 0.]
[ 2. 60. 0.]
[ 2. 120. 0.]
[ 2. -180. 0.]
[ 2. -120. 0.]
[ 2. -60. 0.]]
This differs from the original input X because of the scaling
factors, and the wrapping around angles are reported in the
range [-180,180].
"""
f = np.zeros_like(self)
theta = (scale[1]*angle_spec) * self[..., dir[1]]
r = scale[0] * self[..., dir[0]]
f[..., 0] = r*np.cos(theta)
f[..., 1] = r*np.sin(theta)
f[..., 2] = scale[2] * self[..., dir[2]]
return f
[docs] def hyperCylindrical(self, dir=(0, 1, 2), scale=(1., 1., 1.),
rfunc=None, zfunc=None, angle_spec=at.DEG):
"""Convert cylindrical coordinates to cartesian with advanced scaling.
This is similar to :meth:`cylindrical` but allows the specification
of two functions defining extra scaling factors for the r and z
directions that are dependent on the theta value.
Parameters
----------
(dir, scale, angle_spec): see :meth:`cylindrical`
rfunc: callable, optional
Function r(theta) taking one, float parameter and returning a float.
Like scale[0] it is multiplied with the provided r values before
converting them to cartesian coordinates.
zfunc: callable, optional
Function z(theta) taking one float parameter and returning a float.
Like scale[2] it is multiplied with the provided z values before
converting them to cartesian coordinates.
See Also
--------
cylindrical: similar but without the rfunc and zfunc options.
"""
if rfunc is None:
rfunc = lambda x: 1
if zfunc is None:
zfunc = lambda x: 1
f = np.zeros_like(self)
theta = (scale[1]*angle_spec) * self[..., dir[1]]
r = scale[0] * rfunc(theta) * self[..., dir[0]]
f[..., 0] = r * np.cos(theta)
f[..., 1] = r * np.sin(theta)
f[..., 2] = scale[2] * zfunc(theta) * self[..., dir[2]]
return f
[docs] def toCylindrical(self, dir=(0, 1, 2), angle_spec=at.DEG):
"""Converts from cartesian to cylindrical coordinates.
Returns a Coords where the values are the coordinates of the
input points in a cylindrical coordinate system. The three axes
of the Coords then correspond to (r, theta, z).
Parameters
----------
dir: tuple of ints
A permutation of (0,1,2) specifying which of the global axes are
the radial, circumferential and axial direction of the
cylindrical coordinate system. Make sure to keep the axes ordering
in order to get a right-handed system.
angle_spec: float, at.DEG or RAD, optional
Multiplication factor for angle coordinates.
The default (at.DEG) returns angles in degrees. Use RAD to
return angles in radians.
Returns
-------
Coords
The cylindrical coordinates of the input points.
See Also
--------
cylindrical: conversion from cylindrical to cartesian coordinates
Examples
--------
see :meth:`cylindrical`
"""
f = np.zeros_like(self)
x, y, z = (self[..., i] for i in dir)
f[..., 0] = np.sqrt(x*x+y*y)
f[..., 1] = at.arctand2(y, x, angle_spec)
f[..., 2] = z
return f
[docs] def spherical(self, dir=(0, 1, 2), scale=(1., 1., 1.),
angle_spec=at.DEG, colat=False):
"""Convert spherical coordinates to cartesian coordinates.
Consider a spherical coordinate system with the global xy-plane as
its equatorial plane and the z-axis as axis. The zero meridional
halfplane is taken along th positive x-axis.
The spherical coordinates of a point are:
- the longitude (theta): the circumferential angle, measured around
the z-axis from the zero-meridional halfplane to the meridional
plane containing the point: this angle normally ranges from -180 to
+180 degrees (or from 0 to 360);
- the latitude (phi): the elevation angle of the point's position
vector, measured from the equatorial plane, positive when the point
is at the positive side of the plane: this angle is normally
restricted to the range from -90 (south pole) to +90 (north pole);
- the distance (r): the radial distance of the point from the origin:
this is normally positive.
This function interpretes the 3 coordinates of the points
as (theta,phi,r) values and computes the corresponding global
cartesian coordinates (x,y,z).
Parameters
----------
dir: tuple of 3 ints, optional
If provided, it is a permutation of (0,1,2) and specifies
which of the current coordinates are interpreted as resp.
longitude(theta), latitude(phi) and distance(r). This allows
the axis to be aligned with any of the global axes.
Default order is (0,1,2), with (0,1) the equatorial plane
and 2 the axis.
Beware that using a permutation that is not conserving the order
of the globale axes (0,1,2), may lead to a confusing left-handed
system.
scale: tuple of 3 floats, optional
Scaling factors that are applied on the coordinate values prior
to making the conversion from spherical to cartesian coordinates.
These factors are always given in the order (theta,phi,rz),
irrespective of the permutation by `dir`.
angle_spec: float, at.DEG or RAD, optional
Multiplication factor for angle coordinates.
The default (at.DEG) interpretes the angles in degrees. Use RAD to
specify the angles in radians.
colat: bool
If True, the second coordinate is the colatitude instead. The
colatitude is the angle measured from the north pole towards
the south. In degrees, it is equal to ``90 - latitude`` and
ranges from 0 to 180.
Applications that deal with regions around the pole may
benefit from using this option.
Returns
-------
Coords
The global coordinates of the points that were specified with
spherical coordinates as input.
See Also
--------
toSpherical: the inverse transformation (cartesian to spherical)
cylindrical: similar function for spherical coordinates
Examples
--------
>>> X = Coords('0123').scale(90).trl(2,1.)
>>> X
Coords([[ 0., 0., 1.],
[ 90., 0., 1.],
[ 90., 90., 1.],
[ 0., 90., 1.]])
>>> X.spherical()
Coords([[ 1., 0., 0.],
[-0., 1., 0.],
[ 0., -0., 1.],
[-0., -0., 1.]])
Note that the last two points, though having different spherical
coordinates, are coinciding at the north pole.
"""
f = self.reshape((-1, 3))
theta = (scale[0]*angle_spec) * f[:, dir[0]]
phi = (scale[1]*angle_spec) * f[:, dir[1]]
r = scale[2] * f[:, dir[2]]
if colat:
phi = 90.0*angle_spec - phi
rc = r*np.cos(phi)
f = np.column_stack([rc*np.cos(theta), rc*np.sin(theta), r*np.sin(phi)])
return Coords(f.reshape(self.shape))
[docs] def superSpherical(self, n=1.0, e=1.0, k=0.0, dir=(0, 1, 2),
scale=(1., 1., 1.), angle_spec=at.DEG, colat=False):
"""Performs a superspherical transformation.
superSpherical is much like :meth:`spherical`, but adds some extra
parameters to enable the quick creation of a wide range of complicated
shapes.
Again, the input coordinates are interpreted as
the longitude, latitude and distance in a spherical coordinate system.
Parameters
----------
n: float, >=0
Exponent defining the variation of the distance in nort-south
(latitude) direction. The default value 1 turns constant r-values
into circular meridians. See notes.
e: float, >=0
Exponent defining the variation of the distance in nort-south
(latitude) direction. The default value 1 turns constant r-values
into a circular latitude lines. See notes.
k: float, -1 < k < 1
Eggness factor. If nonzero, creates asymmetric northern and
southern hemisheres. Values > 0 enlarge the southern hemisphere
and shrink the northern, while negative values yield the
opposite.
dir: tuple of 3 ints, optional
If provided, it is a permutation of (0,1,2) and specifies
which of the current coordinates are interpreted as resp.
longitude(theta), latitude(phi) and distance(r). This allows
the axis to be aligned with any of the global axes.
Default order is (0,1,2), with (0,1) the equatorial plane
and 2 the axis.
Beware that using a permutation that is not conserving the order
of the globale axes (0,1,2), may lead to a confusing left-handed
system.
scale: tuple of 3 floats, optional
Scaling factors that are applied on the coordinate values prior
to making the conversion from spherical to cartesian coordinates.
These factors are always given in the order (theta,phi,rz),
irrespective of the permutation by `dir`.
angle_spec: float, at.DEG or RAD, optional
Multiplication factor for angle coordinates.
The default (at.DEG) interpretes the angles in degrees. Use RAD to
specify the angles in radians.
colat: bool
If True, the second coordinate is the colatitude instead. The
colatitude is the angle measured from the north pole towards
the south. In degrees, it is equal to ``90 - latitude`` and
ranges from 0 to 180.
Applications that deal with regions around the pole may
benefit from using this option.
Raises
------
ValueError
If one of `n`, `e` or `k` is out of the acceptable range.
Notes
-----
Values of `n` and `e` should not be negative. Values equal to 1
create a circular shape. Other values keep the radius at angles
corresponding to mmultiples of 90 degrees, while the radius at the
intermediate 45 degree angles will be maximally changed. Values
larger than 1 shrink at 45 degrees directions, while lower values
increase it. A value 2 creates a straight line between the 90 degrees
points (the radius at 45 degrees being reduced to 1/sqrt(2).
See also example SuperShape.
Examples
--------
>>> X = Coords('02222').scale(22.5).trl(2,1.)
>>> X
Coords([[ 0. , 0. , 1. ],
[ 0. , 22.5, 1. ],
[ 0. , 45. , 1. ],
[ 0. , 67.5, 1. ],
[ 0. , 90. , 1. ]])
>>> X.superSpherical(n=3).toSpherical()
Coords([[ 90. , 0. , 1. ],
[ 85.93, 0. , 0.79],
[ 45. , 0. , 0.5 ],
[ 4.07, 0. , 0.79],
[ -0. , -0. , 1. ]])
The result is smaller radius at angle 45.
"""
if n < 0. or e < 0. or k <= -1. or k >= 1.:
raise ValueError("n, e or k out of acceptable range")
def c(o, m):
c = np.cos(o)
return np.sign(c)*abs(c)**m
def s(o, m):
c = np.sin(o)
return np.sign(c)*abs(c)**m
f = self.reshape((-1, 3))
theta = (scale[0]*angle_spec) * f[:, dir[0]]
phi = (scale[1]*angle_spec) * f[:, dir[1]]
r = scale[2] * f[:, dir[2]]
if colat:
phi = 90.0*angle_spec - phi
rc = r*c(phi, n)
if k != 0: # k should be > -1.0 !!!!
x = np.sin(phi)
rc *= (1.-k*x)/(1.+k*x)
f = np.column_stack([rc*c(theta, e), rc*s(theta, e), r*s(phi, n)])
return Coords(f.reshape(self.shape))
[docs] def toSpherical(self, dir=[0, 1, 2], angle_spec=at.DEG):
"""Converts from cartesian to spherical coordinates.
Returns a Coords where the values are the coordinates of the
input points in a spherical coordinate system. The three axes
of the Coords then correspond to (theta, phi, r).
Parameters
----------
dir: tuple of ints
A permutation of (0,1,2) specifying how the spherical coordinate
system is oriented in the global axes. The last value is the axis
of the system; the first two values are the equatorial plane;
the first and last value define the meridional zero plane.
Make sure to preserve the axes ordering in order to get a
right-handed system.
angle_spec: float, at.DEG or RAD, optional
Multiplication factor for angle coordinates.
The default (at.DEG) returns angles in degrees. Use RAD to
return angles in radians.
Returns
-------
Coords
The spherical coordinates of the input points.
See Also
--------
spherical: conversion from spherical to cartesian coordinates
Examples
--------
See :meth:`superSpherical`
"""
v = self[..., dir].reshape((-1, 3))
dist = at.length(v)
long = at.arctand2(v[:, 0], v[:, 2], angle_spec)
lat = np.where(dist <= 0.0, 0.0, at.arcsind(v[:, 1]/dist, angle_spec))
f = np.column_stack([long, lat, dist])
return Coords(f.reshape(self.shape))
[docs] def circulize(self, n):
"""Transform sectors of a regular polygon into circular sectors.
Parameters
----------
n: int
Number of edges of the regular polygon.
Returns
-------
Coords
A Coords where the points inside each sector of a n-sided
regular polygon around the origin are reposition to fill
a circular sector. The polygon is in the x-y-plane and has a
vertex on the x-axis.
Notes
-----
Points on the x-axis and on radii at i * 360 / n degrees are not moved.
Points on the bisector lines between these radii are move maximally
outward. Points on a regular polygon will become points on a circle
if circulized with parameter n equal to the number of sides of the
polygon.
Examples
--------
>>> Coords([[1.,0.],[0.5,0.5],[0.,1.]]).circulize(4)
Coords([[ 1. , 0. , 0. ],
[ 0.71, 0.71, 0. ],
[-0. , 1. , 0. ]])
"""
if n < 3:
raise ValueError("n should be at least 3")
angle = 360./n
X = self.toCylindrical()
t = X.y / angle # ranges from 0 to 1 for sector 0..angle degrees
# Reduce values to a single sector
while t.min() < 0.0:
t[t<0.0] += 1.0
while t.max() > 1.0:
t[t>1.0] -= 1.0
u = abs(0.5-t) * angle
c = at.cosd(u) / at.cosd(angle/2)
X.x *= c
return X.cylindrical()
[docs] def bump(self, dir, a, func=None, dist=None, xb=1.):
"""Create a 1-, 2-, or 3-dimensional bump in a Coords.
A bump is a local modification of the coordinates of a collection
of points. The bump can be 1-, 2- or 3-dimensional, meaning that
the intensity of the coordinate modification varies in 1, 2 or 3
axis directions. In all cases, the bump only changes one coordinate
of the points.
This method can produce various effects, but one of the most common
uses is to force a surface to be indented at some point.
Parameters
----------
dir: int, one of (0,1,2)
The axis of the coordinates to be modified.
a: point (3,)
The point that sets the bump location and intensity.
func: callable, optional
A function that returns the bump intensity in function
of the distance from the bump point `a`. The distance is the
Euclidean distance over all directions except `dir`.
The function takes a single (positive) float value and
returns a float (the bump intensity). Its value should
not be zero at the origin. The function may include constants,
which can be specified as `xb`. If no function is specified,
the default function will be used:
``lambda x: np.where(x<xb,1.-(x/3)**2,0)``
This makes the bump quadratically die out over a distance `xb`.
dist: int or tuple of ints, optional
Specifies how the distance from points to the bump point `a` is
measured. It can be a single axis number (0,1,2) or a tuple of
two or three axis numbers. If a single axis, the bump
will vary only in one direction and distance is measured
along that direction and is signed.
If two or three axes, distance is the (always positive)
euclidean distance over these directions and the bump will
vary in these directions. Default value is the set of 3 axes
minus the direction of modification `dir`.
xb: float or list of floats
Constant(s) to be used in func. Often, this includes the
distance over which the bump will extend. The default
bump function will reach zero at this distance.
Returns
-------
Coords
A Coords with same shape as input, but having a localized
change of coordinates as specified by the parameters.
Notes
-----
This function replaces the `bump1` and `bump2` functions in older
pyFormex versions. The default value of `dist` makes it work like
`bump2`. Specifyin a single axis for `dist` makes it work like `bump1`.
See also examples BaumKuchen, Circle, Clip, Novation
Examples
--------
One-dimensional bump in a linear set of points.
>>> X = Coords(np.arange(6).reshape(-1,1))
>>> X.bump1(1,[3.,5.,0.],dist=0)
Coords([[ 0., 0., 0.],
[ 1., 0., 0.],
[ 2., 0., 0.],
[ 3., 5., 0.],
[ 4., 0., 0.],
[ 5., 0., 0.]])
>>> X.bump(1,[3.,5.,0.],dist=0,xb=3.)
Coords([[ 0. , 0. , 0. ],
[ 1. , 2.78, 0. ],
[ 2. , 4.44, 0. ],
[ 3. , 5. , 0. ],
[ 4. , 4.44, 0. ],
[ 5. , 2.78, 0. ]])
Create a grid a points in xz-plane, with a bump in direction y
with a maximum 5 at x=1.5, z=0., extending over a distance 2.5.
>>> X = Coords(np.arange(4).reshape(-1,1)).replicate(4,dir=2)
>>> X.bump(1,[1.5,5.,0.],xb=2.5)
Coords([[[ 0. , 3.75, 0. ],
[ 1. , 4.86, 0. ],
[ 2. , 4.86, 0. ],
[ 3. , 3.75, 0. ]],
<BLANKLINE>
[[ 0. , 3.19, 1. ],
[ 1. , 4.31, 1. ],
[ 2. , 4.31, 1. ],
[ 3. , 3.19, 1. ]],
<BLANKLINE>
[[ 0. , 0. , 2. ],
[ 1. , 2.64, 2. ],
[ 2. , 2.64, 2. ],
[ 3. , 0. , 2. ]],
<BLANKLINE>
[[ 0. , 0. , 3. ],
[ 1. , 0. , 3. ],
[ 2. , 0. , 3. ],
[ 3. , 0. , 3. ]]])
"""
if func is None:
func = lambda x: np.where(abs(x)<xb, 1.-(x/3)**2, 0)
if func(0.) == 0.:
raise ValueError("Invalid func: f(0)=0")
f = self.copy()
if dist is None:
dist = ((dir+1) % 3, (dir+2) % 3)
if at.isInt(dist):
dist = (dist,)
d = f[..., dist[0]] - a[dist[0]]
if len(dist) > 1:
# compute euclidean distance
d = d*d
for i in dist[1:]:
d1 = f[..., i] - a[i]
d += d1*d1
d = np.sqrt(d)
f[..., dir] += func(d)*a[dir]/func(0)
return f
[docs] def flare(self, xf, f, dir=(0, 2), end=0, exp=1.):
"""Create a flare at the end of a :class:`Coords` block.
A flare is a local change of geometry (widening, narrowing)
at the end of a structure.
Parameters
----------
xf: float
Length over which the local change occurs, measured along ``dir[0]``.
f: float
Maximum amplitude of the flare, in the direction ``dir[1]``.
dir: tuple of two ints (0,1,2)
Two axis designations. The first axis defines the direction along
which the flare decays. The second is the direction of the
coordinate modification.
end: 0 or 1
With end=0, the flare exists at the end with the smallest
coordinates in ``dir[0]]`` direction; with end=1, at the
end with the highest coordinates.
exp: float
Exponent setting the speed of decay of the flare. The default
makes the flare change linearly over the length `f`.
Returns
-------
Coords
A Coords with same shape as the input, but having a localized
change of coordinates at one end of the point set.
Examples
--------
>>> Coords(np.arange(6).reshape(-1,1)).flare(3.,1.6,(0,1),0)
Coords([[ 0. , 1.6 , 0. ],
[ 1. , 1.07, 0. ],
[ 2. , 0.53, 0. ],
[ 3. , 0. , 0. ],
[ 4. , 0. , 0. ],
[ 5. , 0. , 0. ]])
"""
ix, iz = dir
bb = self.bbox()
if end == 0:
xmin = bb[0][ix]
endx = self.test(dir=ix, max=xmin+xf)
func = lambda x: (1.-(x-xmin)/xf) ** exp
else:
xmax = bb[1][ix]
endx = self.test(dir=ix, min=xmax-xf)
func = lambda x: (1.-(xmax-x)/xf) ** exp
x = self.copy()
x[endx, iz] += f * func(x[endx, ix])
return x
[docs] def map(self, func):
"""Map a :class:`Coords` by a 3-D function.
This allows any mathematical transformation being applied to the
coordinates of the Coords.
Parameters
----------
func: callable
A function taking three float arguments (x,y,z coordinates of a
point) and returning a tuple of three float values: the new
coordinate values to replace (x,y,z).
The function must be applicable to NumPy arrays, so it should
only include numerical operations and functions understood by the
numpy module.
Often an inline lambda function is used, but a normally defined
function will work as well.
Returns
-------
Coords object
The input Coords mapped through the specified function
See Also
--------
map1: apply a 1-dimensional mapping to one coordinate direction
mapd: map one coordinate by a function of the distance to a point
Notes
-----
See also examples Cones, Connect, HorseTorse, Manantiales, Mobius,
ScallopDome
Examples
--------
>>> print(Coords([[1.,1.,1.]]).map(lambda x,y,z: [2*x,3*y,4*z]))
[[ 2. 3. 4.]]
"""
# we flatten coordinate sets to ease use of complicated functions
# we should probably do this for map1 and mapd too
X = self.points()
f = np.zeros_like(X)
f[..., 0], f[..., 1], f[..., 2] = func(X.x, X.y, X.z)
return f.reshape(self.shape)
[docs] def map1(self, dir, func, x=None):
"""Map one coordinate by a 1-D function of one coordinate.
Parameters
----------
dir: int (0,1 or 2)
The coordinate axis to be modified.
func: callable
Function taking a single float argument (the coordinate `x`)
and returning a float value: the new coordinate to replace the
`dir` coordinate.
The function must be applicable to NumPy arrays, so it should
only include numerical operations and functions understood by the
numpy module.
Often an inline lambda function is used, but a normally defined
function will work as well.
x: int(0,1,2), optional
If provided, specifies the coordinate that is used as argument
in `func`. Default is to use the same as `dir`.
Returns
-------
Coords object
The input Coords where the `dir` coordinate has been mapped
through the specified function.
See Also
--------
map: apply a general 3-dimensional mapping function
mapd: map one coordinate by a function of the distance to a point
Notes
-----
See also example SplineSurface
Examples
--------
>>> Coords(np.arange(4).reshape(-1,1)).map1(1,lambda x:0.1*x,0)
Coords([[ 0. , 0. , 0. ],
[ 1. , 0.1, 0. ],
[ 2. , 0.2, 0. ],
[ 3. , 0.3, 0. ]])
"""
if x is None:
x = dir
f = self.copy()
f[..., dir] = func(self[..., x])
return f
[docs] def mapd(self, dir, func, point=(0., 0., 0.), dist=None):
"""Map one coordinate by a function of the distance to a point.
Parameters
----------
dir: int (0, 1 or 2)
The coordinate that will be replaced with ``func(d)``, where `d`
is calculated as the distance to `point`.
func: callable
Function taking one float argument (distance to `point`) and
returning a float: the new value for the `dist` coordinate.
`dir` coordinate.
The function must be applicable to NumPy arrays, so it should
only include numerical operations and functions understood by the
numpy module.
Often an inline lambda function is used, but a normally defined
function will work as well.
point: float :term:`array_like` (3,)
The point to where the distance is computed.
dist: int or tuple of ints (0, 1, 2)
The coordinate directions that are used to compute the distance
to `point`. The default is to use 3-D distances.
Examples
--------
Map a regular 4x4 point grid in the xy-plane onto a sphere with
radius 1.5 and center at the corner of the grid.
>>> from .simple import regularGrid
>>> X = Coords(regularGrid([0.,0.],[1.,1.],[3,3]))
>>> X.mapd(2,lambda d:np.sqrt(1.5**2-d**2),X[0,0],[0,1])
Coords([[[ 0. , 0. , 1.5 ],
[ 0.33, 0. , 1.46],
[ 0.67, 0. , 1.34],
[ 1. , 0. , 1.12]],
<BLANKLINE>
[[ 0. , 0.33, 1.46],
[ 0.33, 0.33, 1.42],
[ 0.67, 0.33, 1.3 ],
[ 1. , 0.33, 1.07]],
<BLANKLINE>
[[ 0. , 0.67, 1.34],
[ 0.33, 0.67, 1.3 ],
[ 0.67, 0.67, 1.17],
[ 1. , 0.67, 0.9 ]],
<BLANKLINE>
[[ 0. , 1. , 1.12],
[ 0.33, 1. , 1.07],
[ 0.67, 1. , 0.9 ],
[ 1. , 1. , 0.5 ]]])
"""
f = self.copy()
if dist is None:
dist = [0, 1, 2]
try:
ld = len(dist)
except TypeError:
ld = 1
dist = [dist]
d = f[..., dist[0]] - point[dist[0]]
if ld==1:
d = abs(d)
else:
d = d*d
for i in dist[1:]:
d1 = f[..., i] - point[i]
d += d1*d1
d = np.sqrt(d)
f[..., dir] = func(d)
return f
[docs] def copyAxes(self, i, j, other=None):
"""Copy the coordinates along the axes j to the axes i.
Parameters
----------
i: int (0,1 2) or tuple of ints (0,1,2)
One or more coordinate axes that should have replaced their
coordinates by those along the axes `j`.
j: int (0,1 2) or tuple of ints (0,1,2)
One or more axes whose coordinates should be copied along the
axes `i`. `j` should have the same type and length as `i`.
other: Coords object, optional
If provided, this is the source Coords for the coordinates. It
should have the same shape as self. The default is to take the
coords from self.
Returns
-------
Coords object
A Coords where the coordinates along axes `i` have been replaced
by those along axes `j`.
Examples
--------
>>> X = Coords([[1],[2]]).trl(2,5)
>>> X
Coords([[ 1., 0., 5.],
[ 2., 0., 5.]])
>>> X.copyAxes(1,0)
Coords([[ 1., 1., 5.],
[ 2., 2., 5.]])
>>> X.copyAxes((0,1),(1,0))
Coords([[ 0., 1., 5.],
[ 0., 2., 5.]])
>>> X.copyAxes((0,1,2),(1,2,0))
Coords([[ 0., 5., 1.],
[ 0., 5., 2.]])
"""
if other is None:
other = self
f = self.copy()
f[..., i] = other[..., j]
return f
[docs] def swapAxes(self, i, j):
"""Swap two coordinate axes.
Parameters
----------
i: int (0,1,2)
First coordinate axis
j: int (0,1,2)
Second coordinate axis
Returns
-------
Coords
A Coords with interchanged `i` and `j` coordinates.
Warning
-------
Coords.swapAxes merely changes the order of the elements
along the last axis of the ndarray.
This is quite different from :meth:`numpy.ndarray.swapaxes`,
which is inherited by the Coords class. The latter method
interchanges the array axes of the ndarray, and will not yield
a valid Coords object if the interchange involves the last axis.
Notes
-----
This is equivalent with ``self.copyAxes((i,j),(j,i))``
Swapping two coordinate axes has the same effect as mirroring
against the bisector plane between the two axes.
Examples
--------
>>> X = Coords(np.arange(6).reshape(-1,3))
>>> X
Coords([[ 0., 1., 2.],
[ 3., 4., 5.]])
>>> X.swapAxes(2,0)
Coords([[ 2., 1., 0.],
[ 5., 4., 3.]])
>>> X.swapaxes(1,0)
array([[ 0., 3.],
[ 1., 4.],
[ 2., 5.]])
"""
order = [0, 1, 2]
order[i], order[j] = j, i
return self[..., order]
[docs] def rollAxes(self, n=1):
"""Roll the coordinate axes over the given amount.
Parameters
----------
n: int
Number of positions to roll the axes. With the default (1), the
old axes (0,1,2) become the new axes (2,0,1).
Returns
-------
Coords
A Coords where the coordinate axes of the points have been rolled
over `n` positions.
Notes
-----
``X.rollAxes(1)`` can also be obtained by
``X.copyAxes((0,1,2),(2,0,1))``. It is also equivalent with
a rotation over -120 degrees around the trisectrice of the first
quadrant.
Examples
--------
>>> X = Coords('0123')
>>> X
Coords([[ 0., 0., 0.],
[ 1., 0., 0.],
[ 1., 1., 0.],
[ 0., 1., 0.]])
>>> X.rollAxes(1)
Coords([[ 0., 0., 0.],
[ 0., 1., 0.],
[ 0., 1., 1.],
[ 0., 0., 1.]])
>>> X.rotate(120,axis=[1.,1.,1.])
Coords([[ 0., 0., 0.],
[-0., 1., -0.],
[-0., 1., 1.],
[-0., -0., 1.]])
"""
return np.roll(self, int(n) % 3, axis=-1)
[docs] def projectOnPlane(self, n=2, P=(0., 0., 0.)):
"""Project a :class:`Coords` on a plane.
Creates a parallel projection of the Coords on a plane.
Parameters
----------
n: int (0,1,2) or float :term:`array_like` (3,)
The normal direction to the plane on which to project the Coords.
If an int, it is a global axis.
P: float :term:`array_like` (3,)
A point in the projection plane, by default the global origin.
Returns
-------
Coords
The points of the Coords projected on the specified plane.
Notes
-----
For projection on a plane parallel to a coordinate plane,
it is far more efficient to specify the normal by an axis
number rather than by a three component vector.
This method will also work if any or both of P and n have
the same shape as self, or can be reshaped to the same shape.
This will project each point on its individual plane.
See also example BorderExtension
Examples
--------
>>> X = Coords(np.arange(6).reshape(2,3))
>>> X.projectOnPlane(0,P=[2.5,0.,0.])
Coords([[ 2.5, 1. , 2. ],
[ 2.5, 4. , 5. ]])
>>> X.projectOnPlane([1.,1.,0.])
Coords([[-0.5, 0.5, 2. ],
[-0.5, 0.5, 5. ]])
"""
x = self.reshape(-1, 3).copy()
P = Coords(P).reshape(-1, 3)
if at.isInt(n):
x[:, n] = P[:, n]
else:
n = at.normalize(Coords(n).reshape(-1, 3))
d = at.dotpr(n, x-P).reshape(-1, 1)
x -= d * n
return x.reshape(self.shape)
[docs] def projectOnSphere(self, radius=1., center=(0., 0., 0.)):
"""Project a :class:`Coords` on a sphere.
Creates a central projection of a Coords on a sphere.
Parameters
----------
radius: float, optional
The radius of the sphere, default 1.
center: float :term:`array_like` (3,), optional
The center of the sphere.
The default is the origin of the global axes.
Returns
-------
Coords
A Coords with the input points projected from the center
of the sphere onto its surface.
Notes
-----
Points coinciding with the center of the sphere are returned
unchanged.
This is a central projection from the center of the sphere.
For a parallel projection on a spherical surface, use
:meth:`map`. See the Examples there.
Examples
--------
>>> X = Coords([[x,x,1.] for x in range(1,4)])
>>> X
Coords([[ 1., 1., 1.],
[ 2., 2., 1.],
[ 3., 3., 1.]])
>>> X.projectOnSphere()
Coords([[ 0.58, 0.58, 0.58],
[ 0.67, 0.67, 0.33],
[ 0.69, 0.69, 0.23]])
"""
d = self.distanceFromPoint(center)
with np.errstate(all='ignore'):
s = radius / d
x = (self - center) * s[..., np.newaxis] + center
return x
[docs] def projectOnCylinder(self, radius=1., dir=0, center=[0., 0., 0.]):
"""Project the Coords on a cylinder with axis parallel to a global axis.
Given a cylinder with axis parallel to a global axis, the points
of the Coords are projected from the axis onto the surface of the
cylinder.
The default cylinder has its axis along the x-axis and a unit radius.
No points of the :class:`Coords` should belong to the axis.
Parameters
----------
radius: float, optional
The radius of the sphere, default 1.
dir: int (0,1,2), optional
The global axis parallel to the cylinder's axis.
center: float :term:`array_like` (3,), optional
A point on the axis of the cylinder. Default is the origin of
the global axes.
Returns
-------
Coords
A Coords with the input points projected on the specified cylinder.
Notes
-----
This is a projection from the axis of the cylinder. If you
want a parallel projection on a cylindrical surface, you can use
:meth:`map`.
Examples
--------
>>> X = Coords([[x,x,1.] for x in range(1,4)])
>>> X
Coords([[ 1., 1., 1.],
[ 2., 2., 1.],
[ 3., 3., 1.]])
>>> X.projectOnCylinder()
Coords([[ 1. , 0.71, 0.71],
[ 2. , 0.89, 0.45],
[ 3. , 0.95, 0.32]])
"""
d = self.distanceFromLine(center, at.unitVector(dir))
s = radius / d
c = np.resize(np.asarray(center), self.shape)
c[..., dir] = self[..., dir]
f = self - c
for i in range(3):
if i != dir:
f[..., i] *= s
f += c
return f
[docs] def projectOnSurface(self, S, dir=0, missing='e', return_indices=False):
"""Project a :class:`Coords` on a triangulated surface.
The points of the Coords are projected in the specified direction `dir`
onto the surface S. If a point has multiple projecions in the direction,
the one nearest to the original is returned.
Parameters
----------
S: :class:`~trisurface.TriSurface`
A triangulated surface
dir: int (0,1,2) or float :term:`array_like` (3,)
The direction of the projection, either a global axis direction
or specified as a vector with three components.
missing: 'o', 'r' or 'e'
Specifies how to treat cases where the projective line does not
intersect the surface:
- 'o': return the original point,
- 'r': remove the point from the result.
Use `return_indices` = True to find out which original
points correspond with the projections.
- 'e': raise an exception (default).
return_indices: bool, optional
If True, also returns the indices of the points that have a
projection on the surface.
Returns
-------
x: Coords
A Coords with the projections of the input points on the surface.
With `missing='o'`, this will have the same shape as the input,
but some points might not actually lie on the surface.
With `missing='r'`, the shape will be (npoints,3) and the number
of points may be less than the input.
ind: int array, optional
Only returned if `return_indices` is True: an index in the input
Coords of the points that have a projection on the surface.
With `missing='r'`, this gives the indices of the orginal
points corresponding with the projections.
With `missing='o'`, this can be used to check which points
are located on the surface.
The index is sequential, no matter what the shape of the input
Coords is.
Examples
--------
>>> from pyformex import simple
>>> S = simple.sphere().scale(2).trl([0.,0.,0.2])
>>> x = pattern('0123')
>>> print(x)
[[ 0. 0. 0.]
[ 1. 0. 0.]
[ 1. 1. 0.]
[ 0. 1. 0.]]
>>> xp = x.projectOnSurface(S,[0.,0.,1.])
>>> print(xp)
[[ 0. 0. -1.8 ]
[ 1. 0. -1.52]
[ 1. 1. -1.2 ]
[ 0. 1. -1.53]]
"""
from pyformex import olist
from pyformex.geomtools import anyPerpendicularVector
if missing not in ('e', 'o', 'r'):
raise ValueError("Invalid value for 'missing'")
# try:
# missing = float(missing)
# except Exception:
# if isinstance(missing, str) and len(missing) > 0:
# if missing[0] not in '+-':
# missing = '+' + missing
# missing = missing[:2]
# else:
# missing = None
if at.isInt(dir):
dir = at.unitVector(dir)
else:
dir = np.asarray(dir)
x = self.reshape(-1, 3)
# Create planes through x in direction n
# WE SHOULD MOVE THIS TO geomtools?
v1 = anyPerpendicularVector(dir)
v2 = np.cross(dir, v1)
# Create set of cuts with set of planes
cuts = [S.intersectionWithPlane(xi, v1) for xi in x]
nseg = [c.nelems() for c in cuts]
# remove the empty intersections
cutid = [i for i, n in enumerate(nseg) if n > 0]
cuts = olist.select(cuts, cutid)
# cut the cuts with second set of planes
cuts = [c.toFormex().intersectionWithPlane(xi, v2).coords
for c, xi in zip(cuts, x[cutid])]
npts = [p.shape[0] for p in cuts]
okid = [i for i, n in enumerate(npts) if n > 0]
# remove the empty intersections
cutid = olist.select(cutid, okid)
cuts = olist.select(cuts, okid)
# find the points closest to self
cuts = [p.points()[p.closestToPoint(xi)]
for p, xi in zip(cuts, x[cutid])]
cuts = Coords.concatenate(cuts)
if cuts.shape[0] < x.shape[0]:
if missing == 'e':
raise ValueError(
"The projection of some point(s) in the "
"specified direction does not cut the surface")
elif missing == 'o':
x = x.copy()
x[cutid] = cuts
cuts = x.reshape(self.shape)
if return_indices:
return cuts, cutid
else:
return cuts
# Extra transformations implemented by plugins
[docs] def isopar(self, eltype, coords, oldcoords):
"""Perform an isoparametric transformation on a Coords.
This creates an isoparametric transformation
:class:`~plugins.isopar.Isopar` object
and uses it to transform the input Coords. It is equivalent to::
Isopar(eltype,coords,oldcoords).transform(self)
See :class:`~plugins.isopar.Isopar` for parameters.
"""
from pyformex.plugins.isopar import Isopar
return Isopar(eltype, coords, oldcoords).transform(self)
[docs] def addNoise(self, rsize=0.05, asize=0.0):
"""Add random noise to a Coords.
A random amount is added to each individual coordinate of the Coords.
The maximum difference of the coordinates from their original value
is controled by two parameters `rsize` and `asize` and will not
exceed ``asize+rsize*self.maxsize()``.
Parameters
----------
rsize: float
Relative size of the noise compared with the maximum size
of the input Coords.
asize: float
Absolute size of the noise
Examples
--------
>>> X = Coords(np.arange(6).reshape(2,3))
>>> print((abs(X.addNoise(0.1) - X) < 0.1 * X.sizes()).all())
True
"""
max = asize + rsize * self.maxsize()
return self + at.randomNoise(self.shape, -max, +max)
############################################################################
#
# Transformations that change the shape of the Coords array
#
[docs] def replicate(self, n, dir=0, step=1.):
"""Replicate a Coords n times with a fixed translation step.
Parameters
----------
n: int
Number of times to replicate the Coords.
dir: int (0,1,2) or float :term:`array_like` (3,)
The translation vector. If an int, it specifies a global axis
and the translation is in the direction of that axis.
step: float
If ``dir`` is an int, this is the length of the translation.
Else, it is a multiplying factor applied to the translation
vector.
Returns
-------
Coords
A Coords with an extra first axis with length `n`. The new
shape thus becomes ``(n,) + self.shape``.
The first component along the axis 0 is identical to the
original Coords. Each following component is equal to the
previous translated over `(dir,step)`, where `dir` and `step` are
interpreted just like in the :meth:`translate` method.
Notes
-----
:meth:`rep` is a convenient shorthand for :meth:`replicate`.
Examples
--------
>>> Coords([0.,0.,0.]).replicate(4,1,1.2)
Coords([[ 0. , 0. , 0. ],
[ 0. , 1.2, 0. ],
[ 0. , 2.4, 0. ],
[ 0. , 3.6, 0. ]])
>>> Coords([0.]).replicate(3,0).replicate(2,1)
Coords([[[ 0., 0., 0.],
[ 1., 0., 0.],
[ 2., 0., 0.]],
<BLANKLINE>
[[ 0., 1., 0.],
[ 1., 1., 0.],
[ 2., 1., 0.]]])
"""
n = int(n)
f = np.resize(self, (n,)+self.shape)
if at.isInt(dir):
for i in range(1, n):
f[i, ..., dir] += i*step
else:
dir = Coords(dir, copy=True)
if step != 1.:
dir *= step
for i in range(1, n):
f[i] += i*dir
return Coords(f)
[docs] def split(self):
"""Split the Coords in blocks along first axis.
Returns
-------
list of Coords objects
A list of Coords objects being the subarrays takeb along the
axis 0. The number of objects in the list is ``self.shape[0]``
and each Coords has the shape ``self.shape[1:]``.
Raises
------
ValueError
If ``self.ndim < 2``.
Examples
--------
>>> Coords(np.arange(6).reshape(2,3)).split()
[Coords([ 0., 1., 2.]), Coords([ 3., 4., 5.])]
"""
if self.ndim < 2:
raise ValueError("Can only split arrays with dim >= 2")
return [self[i] for i in range(self.shape[0])]
[docs] def sort(self, order=(0, 1, 2)):
"""Sort points in the specified order of their coordinates.
Parameters
----------
order: int (0,1,2) or tuple of ints (0,1,2)
The order in which the coordinates have to be taken into
account during the sorting operation.
Returns
-------
int array
An index into the sequential point list ``self.points()``
thus that the points are sorted in order of the specified
coordinates.
Examples
--------
>>> X = Coords([[5,3,0],[2,4,3],[2,3,3],[5,6,2]])
>>> X.sort()
array([2, 1, 0, 3])
>>> X.sort((2,1,0))
array([0, 3, 2, 1])
>>> X.sort(1)
array([0, 2, 1, 3])
"""
if at.isInt(order):
order = (order,)
return at.sortByColumns(self.points()[:, order])
[docs] def boxes(self, ppb=1, shift=0.5, minsize=1.e-5):
"""Create a grid of equally sized boxes spanning the :class:`Coords`.
A regular 3D grid of equally sized boxes is created enclosing all
the points of the Coords. The size, position and number of boxes
are determined from the specified parameters.
Parameters
----------
ppb: int
Average number of points per box. The box sizes and number
of boxes will be determined to approximate this number.
shift: float (0.0 .. 1.0)
Relative shift value for the grid. Applying a shift of 0.5
will make the lowest coordinate values fall at the center
of the outer boxes.
minsize: float
Absolute minimal size of the boxes, in each coordinate direction.
Returns
-------
ox: float array (3,)
The minimal coordinates of the box grid.
dx: float array (3,)
The box size in the three global axis directions.
nx: int array (3,)
Number of boxes in each of the coordinate directions.
Notes
-----
The primary purpose of this method is its use in the :meth:`fuse`
method. The boxes allow to quickly label the points inside each
box with an integer value (the box number), so that it becomes
easy to find close points by their same label.
Because of the possibility that two very close points fall in
different boxes (if they happen to be close to a box border),
procedures based on these boxes are often repeated twice, with
a different shift value.
Examples
--------
>>> X = Coords([[5,3,0],[2,4,3],[2,3,3],[5,6,2]])
>>> print(*X.boxes())
[ 0.5 1.5 -1.5] [ 3. 3. 3.] [2 2 2]
>>> print(* X.boxes(shift=0.1))
[ 1.7 2.7 -0.3] [ 3. 3. 3.] [2 2 2]
>>> X = Coords([[1.,1.,0.],[1.001,1.,0.],[1.1,1.,0.]])
>>> print(*X.boxes())
[ 0.98 0.98 -0.02] [ 0.03 0.03 0.03] [4 1 1]
"""
# serialize points
x = self.reshape(-1, 3)
nnod = x.shape[0]
# Calculate box size
lo, hi = x.bbox()
sz = hi-lo
esz = sz[sz > 0.0] # only keep the nonzero dimensions
if esz.size == 0:
# All points are coincident
ox = np.zeros(3, dtype=at.Float)
dx = np.ones(3, dtype=at.Float)
nx = np.ones(3, dtype=at.Int)
else:
nboxes = max(1, nnod // ppb) # ideal total number of boxes
vol = esz.prod()
# avoid error message on the global sz/nx calculation
with np.errstate(all='ignore'):
# set ideal box size, but not smaller than minsize
boxsz = max(minsize, (vol/nboxes) ** (1./esz.shape[0]))
nx = (sz/boxsz).astype(np.int32)
dx = np.where(nx>0, sz/nx, boxsz)
# perform the origin shift and adjust nx to make sure we enclose all
ox = lo - dx*shift
ex = ox + dx*nx
adj = np.ceil((hi-ex)/dx).astype(at.Int).clip(min=0)
nx += adj
return ox, dx, nx
[docs] def fuse(self, ppb=1, shift=0.5, rtol=1.e-5, atol=1.e-8, repeat=True):
"""Find (almost) coinciding points and return a compressed set.
This method finds the points that are very close to each other
and replaces them with a single point. See Notes below for
explanation about the method being used and the parameters being
used. In most cases, `atol` and `rtol` are probably the only
ones you want to change from the defaults. Two points are
considered the same if all their coordinates differ less than
the maximum of `atol` and `rtol * self.maxsize()`.
Parameters
----------
ppb: int, optional
Average number of points per box. The box sizes and number
of boxes will be determined to approximate this number.
shift: float (0.0 .. 1.0), optional
Relative shift value for the box grid. Applying a shift of 0.5
will make the lowest coordinate values fall at the center
of the outer boxes.
rtol: float, optional
Relative tolerance used when considering two points for fusing.
atol: float, optional
Absolute tolerance used when considering two points for fusing.
repeat: bool, optional
If True, repeat the procedure with a second shift value.
Returns
-------
coords: Coords object (npts,3)
The unique points obtained from merging the very close points
of a Coords.
index: int array
An index in the unique coordinates array `coords` for each of
the original points. The shape of the index array is equal to
the point shape of the input Coords (``self.pshape()``). All
the values are in the range 0..npts.
Note
----
From the return values ``coords[index]`` will restore the original
Coords (with accuracy equal to the tolerance used in the fuse
operation)
Notes
-----
The procedure works by first dividing the 3D space in a number of
equally sized boxes, with a average population of `ppb` points. The
arguments `pbb` and `shift` are passed to :meth:`boxes` for this
purpose.
The boxes are identified by 3 integer coordinates, from which a
unique integer scalar is computed, which is then used to sort the
points.
Finally only the points inside the same box need to be compared.
Two points are considered equal if all their coordinates differ less
than the maximum of `atol` and `rtol * self.maxsize()`.
Points considered very close are replaced by a single one, and an index
is kept from the original points to the new list of points.
Running the procedure once does not guarantee finding all close nodes:
two close nodes might be in adjacent boxes. The performance hit for
testing adjacent boxes is rather high, and the probability of separating
two close nodes with the computed box limits is very small.
Therefore, the most sensible way is to run the procedure twice, with
a different shift value (they should differ more than the tolerance).
Specifying repeat=True will automatically do this with a second
shift value equal to shift+0.25.
Because fusing points is a very important and frequent step in many
geometrical modeling and conversion procedures, the core part of
this function is available in a C as well as a Python version,
in the module pyformex.lib.misc. The much faster C version will be used
if available.
Examples
--------
>>> X = Coords([[1.,1.,0.],[1.001,1.,0.],[1.1,1.,0.]])
>>> x,e = X.fuse(atol=0.01)
>>> print(x)
[[ 1. 1. 0. ]
[ 1.1 1. 0. ]]
>>> print(e)
[0 0 1]
>>> np.allclose(X,x[e],atol=0.01)
True
"""
from pyformex.lib import misc
if self.size == 0:
# allow empty coords sets
return Coords(), np.array([], dtype=at.Int).reshape(self.pshape())
if repeat:
# Apply twice with different shift value
coords, index = self.fuse(ppb, shift, rtol, atol, repeat=False)
newshift = shift + (0.25 if shift <= 0.5 else -0.25)
coords, index2 = coords.fuse(ppb, newshift, rtol, atol, repeat=False)
index = index2[index]
return coords, index
#########################################
# This is the single pass
x = self.points()
if (self.sizes()==0.).all():
# All points are coincident
e = np.zeros(x.shape[0], dtype=np.int32)
x = x[:1]
return x, e
# Compute boxes
ox, dx, nx = self.boxes(ppb=ppb, shift=shift, minsize=atol)
# Create box coordinates for all nodes
ind = np.floor((x-ox)/dx).astype(np.int32)
# Create unique box numbers in smallest direction first
o = np.argsort(nx)
val = (ind[:, o[2]] * nx[o[2]] + ind[:, o[1]]) * nx[o[1]] + ind[:, o[0]]
# sort according to box number
srt = np.argsort(val)
# rearrange the data according to the sort order
val = val[srt]
x = x[srt]
# make sure we use np.int32 (for the fast C fuse function)
# Using np.int32 limits this procedure to 10**9 points, which is more
# than enough for all practical purposes
x = x.astype(np.float32)
val = val.astype(np.int32)
tol = np.float32(max(rtol*self.maxsize(), atol))
nnod = val.shape[0]
flag = np.ones((nnod,), dtype=np.int32) # 1 = new, 0 = existing node
# new fusing algorithm
sel = np.arange(nnod).astype(np.int32) # replacement unique node nr
misc._fuse(x, val, flag, sel, tol) # fuse the close points
x = x[flag>0] # extract unique nodes
s = sel[np.argsort(srt)] # and indices for old nodes
return (x, s.reshape(self.shape[:-1]))
[docs] def unique(self, **kargs):
"""Returns the unique points after fusing.
This is just like :meth:`fuse` and takes the same arguments,
but only returns the first argument: the unique points in the Coords.
"""
return self.fuse(**kargs)[0]
[docs] def adjust(self, **kargs):
"""Find (almost) identical nodes and adjust them to be identical.
This is like the :meth:`fuse` operation, but it does not fuse the
close neigbours to a single point.
Instead it adjust the coordinates of the points to be identical.
The parameters are the same as for the :meth:`fuse` method.
Returns
-------
Coords
A Coords with the same shape as the input, but where close
points now have identical coordinates.
Examples
--------
>>> X = Coords([[1.,1.,0.],[1.001,1.,0.],[1.1,1.,0.]])
>>> print(X.adjust(atol=0.01))
[[ 1. 1. 0. ]
[ 1. 1. 0. ]
[ 1.1 1. 0. ]]
"""
coords, index = self.fuse(**kargs)
return coords[index]
[docs] def match(self, coords, **kargs):
"""Match points in another :class:`Coords` object.
Find the points from another Coords object that coincide with
(or are very close to) points of ``self``.
This method works by concatenating the serialized point sets of
both Coords and then fusing them.
Parameters
----------
coords: Coords
The Coords object to compare the points with.
**kargs: keyword arguments
Keyword arguments passed to the :meth:`fuse` method.
Returns
-------
: 1-dim int array
The array has a length of `coords.npoints()`. For each point
in `coords` it holds the index of a point in `self` coinciding
with it, or a value -1 if there is no matching point.
If there are multiple matching points in `self`, it is undefined
which one will be returned. To avoid this ambiguity, you can
first fuse the points of `self`.
See Also
--------
hasMatch
fuse
Examples
--------
>>> X = Coords([[1.],[2.],[3.],[1.]])
>>> Y = Coords([[1.],[4.],[2.00001]])
>>> print(X.match(Y))
[ 0 -1 1]
"""
if 'clean' in kargs:
utils.warn('warn_coords_match_changed')
del kargs['clean']
x = Coords.concatenate([self.points(), coords.points()])
c, e = x.fuse(**kargs)
e0, e1 = e[:self.npoints()], e[self.npoints():]
return at.findFirst(e0, e1)
[docs] def hasMatch(self, coords, **kargs):
# TODO: This is incorrect: doubles in self are not reported
# It is documented, but should we fix it or remove this method??
"""Find out which points are also in another Coords object.
Find the points from self that coincide with (or are very close to)
some point of `coords`.
This method is very similar to :meth:`match`, but does not give
information about which point of `self` matches which point of
`coords`.
Parameters
----------
coords: Coords
The Coords object to compare the points with.
**kargs: keyword arguments
Keyword arguments passed to the :meth:`fuse` method.
Returns
-------
int array
A 1-dim int array with the unique sorted indices of the points
in `self` that have a (nearly) matching point in `coords`.
Warning
-------
If multiple points in `self` coincide with the same point in
`coords`, only one index will be returned for this case. To avoid
this, you can fuse `self` before using this method.
See also
--------
match
Examples
--------
>>> X = Coords([[1.],[2.],[3.],[1.]])
>>> Y = Coords([[1.],[4.],[2.00001]])
>>> print(X.hasMatch(Y))
[0 1]
"""
matches = self.match(coords, **kargs)
return np.unique(matches[matches>-1])
[docs] def append(self, coords):
"""Append more coords to a Coords object.
The appended coords should have matching dimensions in all
but the first axis.
Parameters
----------
coords: Coords object
A Coords having a shape with ``shape[1:]`` equal to
``self.shape[1:]``.
Returns
-------
Coords
The concatenated Coords object (self,coords).
Notes
-----
This is comparable to :func:`numpy.append`, but the result
is a :class:`Coords` object, the default axis is the first one
instead of the last, and it is a method rather than a function.
See Also
--------
concatenate: concatenate a list of Coords
Examples
--------
>>> X = Coords([[1],[2]])
>>> Y = Coords([[3],[4]])
>>> X.append(Y)
Coords([[ 1., 0., 0.],
[ 2., 0., 0.],
[ 3., 0., 0.],
[ 4., 0., 0.]])
"""
return Coords(np.append(self, coords, axis=0))
[docs] @classmethod
def concatenate(clas, L, axis=0):
"""Concatenate a list of :class:`Coords` objects.
Class method to concatenate a list of Coords along the given axis.
Parameters
----------
L: list of Coords objects
The Coords objects to be concatenated. All should have the same
shape except for the length of the specified axis.
Returns
-------
Coords
A Coords with at least two dimensions, even when the list contains
only a single Coords with a single point, or is empty.
Raises
------
ValueError
If the shape of the Coords in the list do not match or if
concatenation along the last axis is attempted.
Notes
-----
This is a class method. It is commonly invoked as
``Coords.concatenate``, and if used as a method on a Coords object,
that object will not be included in the list.
It is like :func:`numpy.concatenate` (which it uses internally),
but makes sure to return :class:`Coords` object, and sets the first
axis as default instead of the last (which would not make sense).
See Also
--------
append: append a Coords to self
Examples
--------
>>> X = Coords([1.,1.,0.])
>>> Y = Coords([[2.,2.,0.],[3.,3.,0.]])
>>> print(Coords.concatenate([X,Y]))
[[ 1. 1. 0.]
[ 2. 2. 0.]
[ 3. 3. 0.]]
>>> print(Coords.concatenate([X,X]))
[[ 1. 1. 0.]
[ 1. 1. 0.]]
>>> print(Coords.concatenate([X]))
[[ 1. 1. 0.]]
>>> print(Coords.concatenate([Y]))
[[ 2. 2. 0.]
[ 3. 3. 0.]]
>>> print(X.concatenate([Y]))
[[ 2. 2. 0.]
[ 3. 3. 0.]]
>>> Coords.concatenate([])
Coords([], shape=(0, 3))
>>> Coords.concatenate([[Y],[Y]],axis=1)
Coords([[[ 2., 2., 0.],
[ 3., 3., 0.],
[ 2., 2., 0.],
[ 3., 3., 0.]]])
"""
L2 = np.atleast_2d(*L)
if len(L2) == 0 or max([len(x) for x in L2]) == 0:
return Coords()
if len(L) == 1:
return L2
else:
return Coords(data=np.concatenate(L2, axis=axis))
[docs] @classmethod
def fromstring(clas, s, sep=' ', ndim=3, count=-1):
"""Create a :class:`Coords` object with data from a string.
This uses :func:`numpy.fromstring` to read coordinates from a
string and creates a Coords object from them.
Parameters
----------
s: str
A string containing a single sequence of float numbers separated
by whitespace and a possible separator string.
sep: str
The separator used between the coordinates. If not a space,
all extra whitespace is ignored.
ndim: int,
Number of coordinates per point. Should be 1, 2 or 3 (default).
If 1, resp. 2, the coordinate string only holds x, resp. x,y
values.
count: int, optional
Total number of coordinates to read. This should be a multiple
of `ndim`. The default is to read all the coordinates in the
string.
Returns
-------
Coords
A Coords object with the coordinates read from the string.
Raises
------
ValueError
If count was provided and the string does not contain that exact
number of coordinates.
Notes
-----
For writing the coordinates to a string, :func:`numpy.tostring` can
be used.
Examples
--------
>>> Coords.fromstring('4 0 0 3 1 2 6 5 7')
Coords([[ 4., 0., 0.],
[ 3., 1., 2.],
[ 6., 5., 7.]])
>>> Coords.fromstring('1 2 3 4 5 6',ndim=2)
Coords([[ 1., 2., 0.],
[ 3., 4., 0.],
[ 5., 6., 0.]])
"""
x = np.fromstring(s, dtype=at.Float, sep=sep, count=count)
if count > 0 and x.size != count:
raise ValueError("Number of coordinates read: %s, "
"expected %s!" % (x.size, count))
if x.size % ndim != 0:
raise ValueError("Number of coordinates read: %s, "
"expected a multiple of %s!" % (x.size, ndim))
return Coords(x.reshape(-1, ndim))
[docs] @classmethod
def fromfile(clas, fil, **kargs):
"""Read a :class:`Coords` from file.
This uses :func:`numpy.fromfile` to read coordinates from a file
and create a Coords. Coordinates X, Y and Z for subsequent points
are read from the file. The total number of coordinates on the file
should be a multiple of 3.
Parameters
----------
fil: str or file
If str, it is a file name. An open file object can also be passed
**kargs:
Arguments to be passed to :func:`numpy.fromfile`.
Returns
-------
Coords
A Coords formed by reading all coordinates from the specified file.
Raises
------
ValueError
If the number of coordinates read is not a multiple of 3.
See Also
--------
numpy.fromfile: read an array to file
numpy.tofile: write an array to file
"""
x = np.fromfile(fil, dtype=at.Float, **kargs)
if x.size % 3 != 0:
raise ValueError("Number of coordinates read: %s, "
"should be multiple of 3!" % x.size)
return Coords(x.reshape(-1, 3))
[docs] def interpolate(self, X, div):
"""Create linear interpolations between two Coords.
A linear interpolation of two equally shaped Coords X and Y at
parameter value t is a Coords with the same shape as X and Y
and with coordinates given by ``X * (1.0-t) + Y * t``.
Parameters
----------
X: Coords object
A Coords object with same shape as `self`.
div: :term:`seed`
This parameter is sent through the :func:`arraytools.smartSeed`
to generate a list of parameter values for which to compute the
interpolation. Usually, they are in the range 0.0 (self)
to 1.0 (X). Values outside the range can be used however
and result in linear extrapolations.
Returns
-------
Coords
A Coords object with an extra (first) axis, containing the
concatenation of the interpolations of `self` and `X` at all
parameter values in `div`.
Its shape is (n,) + self.shape, where n is the number of values
in `div`.
Examples
--------
>>> X = Coords([0])
>>> Y = Coords([1])
>>> X.interpolate(Y,4)
Coords([[ 0. , 0. , 0. ],
[ 0.25, 0. , 0. ],
[ 0.5 , 0. , 0. ],
[ 0.75, 0. , 0. ],
[ 1. , 0. , 0. ]])
>>> X.interpolate(Y,[-0.1, 0.5, 1.25])
Coords([[-0.1 , 0. , 0. ],
[ 0.5 , 0. , 0. ],
[ 1.25, 0. , 0. ]])
>>> X.interpolate(Y,(4,0.3,0.2))
Coords([[ 0. , 0. , 0. ],
[ 0.21, 0. , 0. ],
[ 0.47, 0. , 0. ],
[ 0.75, 0. , 0. ],
[ 1. , 0. , 0. ]])
"""
if self.shape != X.shape:
raise RuntimeError("`X` should have same shape as `self`")
div = at.smartSeed(div)
return self + np.outer(div, X-self).reshape((-1,)+self.shape)
[docs] def convexHull(self, dir=None, return_mesh=False):
"""Return the 2D or 3D convex hull of a :class:`Coords`.
Parameters
----------
dir: int (0,1,2), optional
If provided, it is one if the global axes and the 2D convex
hull in the specified viewing direction will be computed.
The default is to compute the 3D convex hull.
return_mesh: bool, optional
If True, returns the convex hull as a :class:`~mesh.Mesh` object
instead of a :class:`~connectivity.Connectivity`.
Returns
-------
:class:`~connectivity.Connectivity` or :class:`~mesh.Mesh`
The default is to return a Connectivity table containing the
indices of the points that constitute the convex hull of the
Coords. For a 3D hull, the Connectivity has plexitude 3, and
eltype 'tri3'; for a 2D hull these are respectively 2 and 'line2'.
The values in the Connectivity refer to the flat points list
as obtained from :meth:`points`.
If `return_mesh` is True, a compacted Mesh is returned
instead of the Connectivity. For a 3D hull, the Mesh will be a
:class:`~trisurface.TriSurface`, otherwise
it is a Mesh of 'line2' elements.
The returned Connectivity or Mesh will be empty if all the points
are in a plane for the 3D version, or an a line in the viewing
direction for the 2D version.
Notes
-----
This uses SciPy to compute the convex hull. You need to have
SciPy version 0.12.0 or higher. On Debian/Ubuntu-likes install
package 'python3-scipy'.
See also example ConvexHull.
"""
from pyformex.plugins import scipy_itf
points = self.points()
if dir is not None and at.isInt(dir):
ind = list(range(3))
ind.remove(dir)
points = points[:, ind]
hull = scipy_itf.convexHull(points)
if return_mesh:
from pyformex.mesh import Mesh
hull = Mesh(self.points(), hull).compact()
if dir is not None and at.isInt(dir):
hull.coords[:, dir] = 0.0
return hull
def actor(self, **kargs):
"""This allows a Coords object to be drawn as Geometry"""
if self.npoints() == 0:
return None
from pyformex.formex import Formex
return Formex(self.reshape(-1, 3)).actor(**kargs)
# Convenient shorter notations
rot = rotate
trl = translate
rep = replicate
# deprecated but kept for compatibility
def bump1(self, dir, a, func=None, dist=0):
return self.bump(dir, a, func, dist=dist)
###########################################################################
##
## functions
##
#########################
[docs]def otherAxes(i):
# TODO: this can be removed
"""Return all global axes except the specified one
Parameters
----------
i: int (0,1,2)
One of the global axes.
Returns
-------
tuple of ints
Two ints (j,k) identifying the other global axes in such order
that (i,j,k) is a right-handed coordinate system.
>>> otherAxes(1)
(2, 0)
"""
return ((i+1) % 3, (i+2) % 3)
[docs]def bbox(objects):
"""Compute the bounding box of a list of objects.
The bounding box of an object is the smallest rectangular cuboid
in the global Cartesian coordinates, such that no points of the
objects lie outside that cuboid. The resulting bounding box of the list
of objects is the smallest bounding box that encloses all the objects
in the list.
Parameters
----------
objects: object or list of objects
One or more (list or tuple) objects that have a method :meth:`bbox`
returning the object's bounding box as a Coords with two points.
Returns
-------
Coords
A Coords object with two points: the first contains the minimal
coordinate values, the second has the maximal ones of the overall
bounding box encompassing all objects.
Notes
-----
Objects that do not have a :meth:`bbox` method or whose :meth:`bbox`
method returns invalid values, are silently ignored.
See Also
--------
Coords.bbox: compute the bounding box of a :class:`Coords` object.
Examples
--------
>>> bbox((Coords([-1.,1.,0.]),Coords([2,-3])))
Coords([[-1., -3., 0.],
[ 2., 1., 0.]])
"""
if not isinstance(objects, (list, tuple)):
objects = [objects]
bboxes = [f.bbox() for f in objects
if hasattr(f, 'bbox') and not np.isnan(f.bbox()).any()]
bboxes = [bb for bb in bboxes if bb is not None]
if len(bboxes) == 0:
o = origin()
bboxes = [[o, o]]
return Coords(np.concatenate(bboxes)).bbox()
[docs]def bboxIntersection(A, B):
"""Compute the intersection of the bounding box of two objects.
Parameters
----------
A: first object
An object having a bbox method returning its boundary box.
B: second object
Another object having a bbox method returning its boundary box.
Returns
-------
Coords (2,3)
A Coords specifying the intersection of the bounding boxes of
the two objects. This again has the format of a bounding box:
a coords with two points: one with the minimal and one with
the maximal coordinates. If the two bounding boxes do not
intersect, an empty Coords is returned.
Notes
-----
Since bounding boxes are Coords objects, it is possible to pass
computed bounding boxes as arguments. The bounding boxes are indeed
their own bounding box.
Examples
--------
>>> A = Coords([[-1.,1.],[2,-3]])
>>> B = Coords([[0.,1.],[4,2]])
>>> C = Coords([[0.,2.],[4,2]])
>>> bbox((A,B))
Coords([[-1., -3., 0.],
[ 4., 2., 0.]])
The intersection of the bounding boxes of A and B
degenerates into a line segment parallel to the x-axis:
>>> bboxIntersection(A,B)
Coords([[ 0., 1., 0.],
[ 2., 1., 0.]])
The bounding boxes of A and C do not intersect:
>>> bboxIntersection(A,C)
Coords([], shape=(0, 3))
"""
Amin, Amax = A.bbox()
Bmin, Bmax = B.bbox()
min = np.where(Amin>Bmin, Amin, Bmin)
max = np.where(Amax<Bmax, Amax, Bmax)
if (min > max).any():
bb = Coords()
else:
bb = Coords([min, max])
return bb
[docs]def origin():
"""ReturnCreate a Coords holding the origin of the global coordinate system.
Returns
-------
Coords (3,)
A Coords holding a single point with coordinates (0.,0.,0.).
Exmaples
--------
>>> origin()
Coords([ 0., 0., 0.])
"""
return Coords(np.zeros((3)))
[docs]def pattern(s, aslist=False):
"""Generate a sequence of points on a regular grid.
This function creates a sequence of points that are on a regular grid
with unit step. These points are created from a simple string input,
interpreting each character as a code specifying how to move from the
last to the next point.
The start position is always the origin (0.,0.,0.).
Currently the following codes are defined:
- 0 or +: goto origin (0.,0.,0.)
- 1..8: move in the x,y plane
- 9 or .: remain at the same place (i.e. duplicate the last point)
- A..I: same as 1..9 plus step +1. in z-direction
- a..i: same as 1..9 plus step -1. in z-direction
- /: do not insert the next point
Any other character raises an error.
When looking at the x,y-plane with the x-axis to the right and the
y-axis up, we have the following basic moves:
1 = East, 2 = North, 3 = West, 4 = South, 5 = NE, 6 = NW, 7 = SW, 8 = SE.
Adding 16 to the ordinal of the character causes an extra move of +1. in
the z-direction. Adding 48 causes an extra move of -1. This means that
'ABCDEFGHI', resp. 'abcdefghi', correspond with '123456789' with an extra
z +/-= 1. This gives the following schema::
z+=1 z unchanged z -= 1
F B E 6 2 5 f b e
| | |
| | |
C----I----A 3----9----1 c----i----a
| | |
| | |
G D H 7 4 8 g d h
The special character '/' can be put before any character to make the
move without inserting the new point. The string should start
with a '0' or '9' to include the starting point (the origin) in the output.
Parameters
----------
s: str
A string with characters generating subsequent points.
aslist: bool, optional
If True, the points are returned as lists of **integer**
coordinates instead of a :class:`Coords` object.
Returns
-------
Coords or list of ints
The default is to return the generated points as a Coords.
With ``aslist=True`` however, the points are returned as a list
of tuples holding 3 integer grid coordinates.
See Also
--------
xpattern
Examples
--------
>>> pattern('0123')
Coords([[ 0., 0., 0.],
[ 1., 0., 0.],
[ 1., 1., 0.],
[ 0., 1., 0.]])
>>> pattern('2'*4)
Coords([[ 0., 1., 0.],
[ 0., 2., 0.],
[ 0., 3., 0.],
[ 0., 4., 0.]])
"""
x = y = z = 0
L = []
insert = True
for c in s:
if c == '/':
insert = False
continue
elif c == '0' or c == '+':
x = y = z = 0
elif c == '.':
pass
else:
j, i = divmod(ord(c), 16)
if j == 3:
pass
elif j == 4:
z += 1
elif j == 6:
z -= 1
else:
raise RuntimeError("Unknown character '%c' in pattern input" % c)
if i == 1:
x += 1
elif i == 2:
y += 1
elif i == 3:
x -= 1
elif i == 4:
y -= 1
elif i == 5:
x += 1
y += 1
elif i == 6:
x -= 1
y += 1
elif i == 7:
x -= 1
y -= 1
elif i == 8:
x += 1
y -= 1
elif i == 9:
pass
else:
raise RuntimeError("Unknown character '%c' in pattern input" % c)
if insert:
L.append((x, y, z))
insert = True
if not aslist:
L = Coords(L)
return L
[docs]def xpattern(s, nplex=1):
"""Create a Coords object from a string pattern.
Create a sequence of points using :func:`pattern`, and groups the
points by ``nplex`` to create a Coords with shape ``(-1,nplex,3)``.
Parameters
----------
s: str
The string to pass to :func:`pattern` to produce the sequence
of points.
nplex: int
The number of subsequent points to group together to create
the structured Coords.
Returns
-------
Coords
A Coords with shape (-1,nplex,3).
Raises
------
ValueError
If the number of points produced by the input string `s` is not
a multiple of `nplex`.
Examples
--------
>>> print(xpattern('.12.34',3))
[[[ 0. 0. 0.]
[ 1. 0. 0.]
[ 1. 1. 0.]]
<BLANKLINE>
[[ 1. 1. 0.]
[ 0. 1. 0.]
[ 0. 0. 0.]]]
"""
x = Coords(pattern(s))
try:
return x.reshape(-1, nplex, 3)
except Exception:
raise ValueError("Could not reshape points list to plexitude %s" % nplex)
[docs]def align(L, align, offset=(0., 0., 0.)):
"""Align a list of geometrical objects.
Parameters
----------
L: list of Coords or Geometry objects
A list of objects that have an appropriate ``align`` method,
like the :class:`Coords` and :class:`~geometry.Geometry`
(and its subclasses).
align: str
A string of three characters, one for each coordinate direction,
that define how the subsequent objects have to be aligned in each of
the global axis directions:
- '-' : align on the minimal coordinate value
- '+' : align on the maximal coordinate value
- '0' : align on the middle coordinate value
- '|' : align the minimum value on the maximal value of the
previous item
Thus the string ``'|--'`` will juxtapose the objects in the x-direction,
while aligning them on their minimal coordinates in the y- and
z- direction.
offset: float :term:`array_like` (3,), optional
An extra translation to be given to each subsequent object. This can
be used to create a space between the objects, instead of
juxtaposing them.
Returns
-------
list of objects
A list with the aligned objects.
Notes
-----
See also example Align.
See Also
--------
Coords.align: align a single object with respect to a point.
"""
r = L[:1]
al = am =''
for i in range(3):
if align[i] == '|':
al += '-'
am += '+'
else:
al += align[i]
am += align[i]
for o in L[1:]:
r.append(o.align(al, r[-1].bboxPoint(am)+offset))
return r
# End
```