# -*- coding: utf-8 -*-
"""
This file is part of FElupe.
FElupe 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.
FElupe 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 FElupe. If not, see <http://www.gnu.org/licenses/>.
"""
import numpy as np
[docs]
class Element:
"""
Base-class for a finite element which provides methods for plotting.
Examples
--------
This example shows how to implement a hexahedron element.
.. pyvista-plot::
:force_static:
>>> import felupe as fem
>>> import numpy as np
>>>
>>> class Hexahedron(fem.Element):
... def __init__(self):
... a = [-1, 1, 1, -1, -1, 1, 1, -1]
... b = [-1, -1, 1, 1, -1, -1, 1, 1]
... c = [-1, -1, -1, -1, 1, 1, 1, 1]
... self.points = np.vstack([a, b, c]).T
...
... # additional attributes for plotting, optional
... self.cells = np.array([[0, 1, 2, 3, 4, 5, 6, 7]])
... self.cell_type = "hexahedron"
...
... def function(self, rst):
... r, s, t = rst
... a, b, c = self.points.T
... ar, bs, ct = 1 + a * r, 1 + b * s, 1 + c * t
... return (ar * bs * ct) / 8
...
... def gradient(self, rst):
... r, s, t = rst
... a, b, c = self.points.T
... ar, bs, ct = 1 + a * r, 1 + b * s, 1 + c * t
... return np.stack([a * bs * ct, ar * b * ct, ar * bs * c], axis=1)
>>>
>>> mesh = fem.Cube(n=6)
>>> element = Hexahedron()
>>> quadrature = fem.GaussLegendre(order=1, dim=3)
>>> region = fem.Region(mesh, element, quadrature)
"""
[docs]
def view(self, point_data=None, cell_data=None, cell_type=None):
"""View the element with optional given dicts of point- and cell-data items.
Parameters
----------
point_data : dict or None, optional
Additional point-data dict (default is None).
cell_data : dict or None, optional
Additional cell-data dict (default is None).
cell_type : pyvista.CellType or None, optional
Cell-type of PyVista (default is None).
Returns
-------
felupe.ViewMesh
A object which provides visualization methods for
:class:`felupe.element.Element`.
See Also
--------
felupe.ViewMesh : Visualization methods for :class:`felupe.Mesh`.
"""
from ..mesh import Mesh
mesh = Mesh(points=self.points, cells=self.cells, cell_type=self.cell_type)
return mesh.view(
point_data=point_data,
cell_data=cell_data,
cell_type=cell_type,
)
[docs]
def plot(
self,
*args,
style="wireframe",
color="black",
add_axes_at_origin=True,
add_point_labels=True,
show_points=True,
font_size=26,
**kwargs,
):
"""Plot the element.
See Also
--------
felupe.Scene.plot: Plot method of a scene.
"""
view = self.view()
if self.points.shape[1] > 1:
view.mesh = view.mesh.extract_surface().extract_feature_edges()
plotter = view.plot(
*args,
show_undeformed=False,
opacity=0.8,
add_axes=False,
show_edges=False,
style=style,
color=color,
**kwargs,
)
if add_point_labels:
plotter.add_point_labels(
points=np.pad(self.points, ((0, 0), (0, 3 - self.points.shape[1]))),
labels=[f"{a}" for a in np.arange(len(self.points))],
font_size=font_size,
show_points=show_points,
point_size=20,
point_color="black",
shape=None,
fill_shape=False,
render_points_as_spheres=True,
always_visible=True,
)
if add_axes_at_origin:
actor = plotter.add_axes_at_origin(xlabel="r", ylabel="s", zlabel="t")
actor.SetNormalizedShaftLength((0.9, 0.9, 0.9))
actor.SetNormalizedTipLength((0.1, 0.1, 0.1))
if self.points.shape[1] == 3:
actor.SetTotalLength([1.3, 1.3, 1.3])
elif self.points.shape[1] == 2:
actor.SetZAxisLabelText("")
actor.SetTotalLength([1.3, 1.3, 0])
elif self.points.shape[1] == 1:
actor.SetYAxisLabelText("")
actor.SetZAxisLabelText("")
actor.SetTotalLength([1.3, 0, 0])
plotter.camera.zoom(0.7)
if self.points.shape[1] == 3:
plotter.camera.azimuth = -17
return plotter
[docs]
def screenshot(
self,
*args,
filename=None,
transparent_background=None,
scale=None,
**kwargs,
):
"""Take a screenshot of the element.
See Also
--------
pyvista.Plotter.screenshot: Take a screenshot of a PyVista plotter.
"""
if filename is None:
filename = f"{self.cell_type}.png"
return self.plot(*args, off_screen=True, **kwargs).screenshot(
filename=filename,
transparent_background=transparent_background,
scale=scale,
)
