# Library of SPAM functions for projecting morphological field onto tetrahedral
# meshes
# Copyright (C) 2020 SPAM Contributors
#
# 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/>.
"""
The ``spam.mesh.projection`` module offers a two functions that enables the construction of three dimensional unstructured meshes (four noded tetrahedra) that embbed heterogeneous data
(namely, **subvolumes** and interface **orientation**) based on eihter:
- the distance field of an **segmented images** (see ``spaM.filters.distanceField``),
- ideal **geometrical objects** (see ``spam.filters.objects``).
>>> import spam.mesh
>>> spam.mesh.projectField(mesh, fields)
>>> spam.mesh.projectObjects(mesh, objects)
NOTE
----
Objects array conventions:
- Sphere: ``[radius, centerX, centerY, centerZ, phase]``
- Cylinder: ``[radius, centerX, centerY, centerZ, directionX, directionY, directionZ, phase]``
Distance field and orientation convention:
- The distance fields inside connected components have positive values
- The normal vectors are pointing outside (to negative values)
- The subvolumes returned correspond to the outside (negative part)
"""
import numpy
from spam.mesh.meshToolkit import projmorpho
def _refactor_mesh(mesh):
"""
Helper private function for projection.
Remove additional nodes and change connectivity matrix accordingly.
"""
points = mesh["points"]
cells = mesh["cells"]
# DEBUG: Artificially add unused node
# points = numpy.insert(points, 10, [-1.0,-1.0,-1.0], axis=0)
# for i, node_number_x4 in enumerate(cells):
# for j, node_number in enumerate(node_number_x4):
# if cells[i, j] >= 10:
# cells[i, j] += 1
# test if unused nodes
cells_set = set(cells.ravel()) # ordered numbering in connectivity
n_points_used = len(cells_set)
if n_points_used != points.shape[0]:
print("Deleting points before projection")
# removing unused nodes
points_to_delete = []
n_deleted = 0
for new, old in enumerate(cells_set):
# check if holes in the connectivity matrix
if new != old - n_deleted:
points_to_delete.append(new + n_deleted)
n_deleted += 1
# print(new, old, n_deleted, old - n_deleted)
points = numpy.delete(points, points_to_delete, axis=0)
print("Renumbering connectivity matrix")
# renumbering connectivity matrix accordingly
new_node_numbering = {old: new + 1 for new, old in enumerate(cells_set)}
for i, node_number_x4 in enumerate(cells):
for j, node_number in enumerate(node_number_x4):
if new_node_numbering[cells[i, j]] != cells[i, j]:
cells[i, j] = new_node_numbering[cells[i, j]]
del cells_set
# check if cell number start by 1 or 0
if cells.min() == 0:
print("Shift connectivity by 1 to start at 1")
cells += 1
return points, cells
[docs]
def projectObjects(
mesh,
objects,
analyticalOrientation=True,
cutoff=1e-6,
writeConnectivity=None,
vtkMesh=False,
):
"""
This function project a set of objects onto an unstructured mesh.
Each objects can be attributed a phase.
Parameters
----------
mesh: dict
Dictionary containing points coordinates and mesh connectivity.
.. code-block:: python
mesh = {
# numpy array of size number of nodes x 3
"points": points,
# numpy array of size number of elements x 4
"cells": connectivity,
}
objects: 2D array
The list of objects. Each line corresponds to an object encoded as follow:
.. code-block:: text
- spheres: radius, oZ, oY, oX, phase
- cylinders: radius, oZ, oY, oX, nZ, nY, nX, phase
analyticalOrientation: bool, default=True
Change how the interface's normals are computed:
- `True`: as the direction from the centroid of the tetrahedron to the closest highest value of the object distance field (ie, the center of a sphere, the axis of a cylinder).
- `False`: as the normals of the facets which points lie on the object surface.
cutoff: float, default=1e-6
Volume ratio below wich elements with interfaces are ignored and considered being part of a single phase.
writeConnectivity: string, default=None
When not None, it writes a text file called `writeConnectivity` the
list of node and the list of elements
which format is:
.. code-block:: text
COORdinates ! number of nodes
nodeId, 0, x, y, z
...
ELEMents ! number of elemens
elemId, 0, elemType, n1, n2, n3, n4, subVol(-), normalX,
normalY, normalZ
...
where:
- ``n1, n2, n3, n4`` is the connectivity (node numbers).
- ``subVol(-)`` is the sub volume of the terahedron inside the inclusion.
- ``normalX, normalY, normalZ`` are to components of the interface normal vector.
- ``elemType`` is the type of element. Their meaning depends on the their phase.
Correspondance can be found in the function output
after the key word **MATE** like:
.. code-block:: text
<projmorpho::set_materials
. field 1
. . MATE,1: background
. . MATE,2: phase 1
. . MATE,3: interface phase 1 with
background
. field 2
. . MATE,1: background
. . MATE,4: phase 2
. . MATE,5: interface phase 2 with
background
>
Sub volumes and interface vector are only relevant for interfaces. Default value is 0 and [1, 0, 0].
vtkMesh: bool, default=False
Writes the VTK of interpolated fields and materials. The files take the same name as ``writeConnectivity``.
Returns
-------
(nElem x 5) array
For each element: ``elemType, subVol(-), normalX, normalY, normalZ`` (see outputFile for details).
NOTE
----
Only four noded tetrahedra meshes are supported.
>>> import spam.mesh
>>> # unstructured mesh
>>> points, cells = spam.mesh.createCuboid([1, 1, 1], 0.1)
>>> mesh = {"points": points, "cells": cells}
>>> # one centered sphere (0.5, 0.5, 0.5) of radius 0.2 (phase 1)
>>> sphere = [[0.2, 0.8, 0.1, 0.1, 1]]
>>> # projection
>>> materials = spam.mesh.projectObjects(mesh, sphere, writeConnectivity="mysphere", vtkMesh=True)
"""
# init projmorpho
pr = projmorpho(
name="spam" if writeConnectivity is None else writeConnectivity,
cutoff=cutoff,
)
# STEP 1: objects
objects = numpy.array(objects)
# if objects.shape[1] == 5:
# swaps = [
# [1, 3], # swap ox <-> oz
# ]
# for a, b in swaps:
# # swap axis for origin point
# tmp = objects[:, a].copy()
# objects[:, a] = objects[:, b]
# objects[:, b] = tmp
# elif objects.shape[1] == 7:
# # swap axis ellipsoids
# tmp = objects[:, 0].copy()
# objects[:, 0] = objects[:, 2]
# objects[:, 2] = tmp
# tmp = objects[:, 3].copy()
# objects[:, 3] = objects[:, 5]
# objects[:, 5] = tmp
# elif objects.shape[1] == 8: # cylinders
# swaps = [
# [1, 3], # swap ox <-> oz
# [4, 6], # swap nx <-> nz
# ]
# for a, b in swaps:
# # swap axis for origin point
# tmp = objects[:, a].copy()
# objects[:, a] = objects[:, b]
# objects[:, b] = tmp
pr.setObjects(objects)
# STEP 2: Mesh
points, cells = _refactor_mesh(mesh)
pr.setMesh(points, cells.ravel())
# STEP 3: projection
pr.computeFieldFromObjects()
pr.projection(analytical_orientation=analyticalOrientation)
# STEP 4: write VTK
if writeConnectivity:
pr.writeFEAP()
if vtkMesh:
pr.writeVTK()
pr.writeInterfacesVTK()
return numpy.array(pr.getMaterials())
[docs]
def projectField(mesh, fields, thresholds=[0.0], cutoff=1e-6, writeConnectivity=None, vtkMesh=False):
"""
This function project a set of distance fields onto an unstructured mesh.
Each distance field corresponds to a phase and the interface between
the two phases is set by the thresholds.
Parameters
----------
mesh: dict
Dictionary containing points coordinates and mesh connectivity.
.. code-block:: python
mesh = {
# numpy array of size number of nodes x 3
"points": points,
# numpy array of size number of elements x 4
"cells": connectivity,
}
fields: list of dicts
The fields should be continuous (like a distance
field) for a better projection. They are discretised over a regular
mesh (lexicographical order) and eahc one corresponds to a phase.
The dictionary containing the fields data is defined as follow
.. code-block:: python
fields = {
# coordinates of the origin of the field (3 x 1)
"origin": origin,
# lengths of fields domain of definition (3 x 1)
"lengths": lengths,
# list of fields values (list of 3D arrays)
"values": [phase1, phase2],
}
thresholds: list of floats, default=[0]
The list of thresholds.
cutoff: float, default=1e-6
Volume ratio below wich elements with interfaces are ignored and considered being part of a single phase.
writeConnectivity: string, default=None
When not None, it writes a text file called `writeConnectivity` the
list of node and the list of elements
which format is:
.. code-block:: text
COORdinates ! number of nodes
nodeId, 0, x, y, z
...
ELEMents ! number of elemens
elemId, 0, elemType, n1, n2, n3, n4, subVol(-), normalX,
normalY, normalZ
...
where:
- ``n1, n2, n3, n4`` is the connectivity (node numbers).
- ``subVol(-)`` is the sub volume of the terahedron inside the inclusion.
- ``normalX, normalY, normalZ`` are to components of the interface normal vector.
- ``elemType`` is the type of element. Their meaning depends on the their phase.
Correspondance can be found in the function output
after the key word **MATE** like:
.. code-block:: text
<projmorpho::set_materials
. field 1
. . MATE,1: background
. . MATE,2: phase 1
. . MATE,3: interface phase 1 with
background
. field 2
. . MATE,1: background
. . MATE,4: phase 2
. . MATE,5: interface phase 2 with
background
>
Sub volumes and interface vector are only relevant for interfaces. Default value is 0 and [1, 0, 0].
vtkMesh: bool, default=False
Writes the VTK of interpolated fields and materials. The files take the same name as ``writeConnectivity``.
Returns
-------
(nElem x 5) array
For each element: ``elemType, subVol(-), normalX, normalY, normalZ`` (see outputFile for details).
NOTE
----
Only four noded tetrahedra meshes are supported.
>>> import spam.mesh
>>> import spam.kalisphera
>>> # unstructured mesh
>>> points, cells = spam.mesh.createCuboid([1, 1, 1], 0.1)
>>> mesh = {"points": points, "cells": cells}
>>> # create an image of a sphere and its distance field
>>> sphereBinary = numpy.zeros([101] * 3, dtype=float)
>>> spam.kalisphera.makeSphere(sphereBinary, [50.5] * 3, 20)
>>> sphereField = spam.mesh.distanceField(one_sphere_binary.astype(bool).astype(int))
>>> # format field object
>>> fields = {
>>> # coordinates of the origin of the field (3 x 1)
>>> "origin": [0] * 3,
>>> # lengths of fields domain of definition (3 x 1)
>>> "lengths": [1] * 3,
>>> # list of fields
>>> "values": [sphereField],
>>> }
>>> # projection
>>> materials = spam.mesh.projectField(mesh, fields, writeConnectivity="mysphere", vtkMesh=True)
"""
# init projmorpho
pr = projmorpho(
name="spam" if writeConnectivity is None else writeConnectivity,
thresholds=thresholds,
cutoff=cutoff,
)
# STEP 1: Fields
# origin
# origin = [_ for _ in reversed(fields["origin"])]
origin = [_ for _ in fields["origin"]]
# nPoints
# nPoints = [n for n in reversed(fields["values"][0].shape)]
nPoints = [n for n in fields["values"][0].shape]
# field size
# lengths = [_ for _ in reversed(fields["lengths"])]
lengths = [_ for _ in fields["lengths"]]
# ravel fields values (ravel in F direction to swap zyx to xyz)
values = [v.flatten(order="F") for v in fields["values"]]
# values = [v.flatten(order='C') for v in fields["values"]]
pr.setImage(values, lengths, nPoints, origin)
# STEP 2: Mesh
points, cells = _refactor_mesh(mesh)
pr.setMesh(points, cells.ravel())
# STEP 3: projection
pr.computeFieldFromImages()
pr.projection()
# STEP 4: write VTK
if writeConnectivity:
pr.writeFEAP()
if vtkMesh:
pr.writeVTK()
pr.writeInterfacesVTK()
return numpy.array(pr.getMaterials())
