83 lines
1.8 KiB
Python
83 lines
1.8 KiB
Python
import sys, os
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# Add the igl library to the modules search path
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sys.path.insert(0, os.getcwd() + "/../")
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import pyigl as igl
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from shared import TUTORIAL_SHARED_PATH, check_dependencies
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dependencies = ["viewer"]
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check_dependencies(dependencies)
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V = igl.eigen.MatrixXd()
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F = igl.eigen.MatrixXi()
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igl.readOFF(TUTORIAL_SHARED_PATH + "camelhead.off", V, F)
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# Find boundary edges
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E = igl.eigen.MatrixXi()
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igl.boundary_facets(F, E)
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# Find boundary vertices
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b = igl.eigen.MatrixXi()
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IA = igl.eigen.MatrixXi()
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IC = igl.eigen.MatrixXi()
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igl.unique(E, b, IA, IC)
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# List of all vertex indices
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vall = igl.eigen.MatrixXi()
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vin = igl.eigen.MatrixXi()
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igl.coloni(0, V.rows() - 1, vall)
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# List of interior indices
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igl.setdiff(vall, b, vin, IA)
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# Construct and slice up Laplacian
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L = igl.eigen.SparseMatrixd()
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L_in_in = igl.eigen.SparseMatrixd()
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L_in_b = igl.eigen.SparseMatrixd()
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igl.cotmatrix(V, F, L)
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igl.slice(L, vin, vin, L_in_in)
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igl.slice(L, vin, b, L_in_b)
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# Dirichlet boundary conditions from z-coordinate
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bc = igl.eigen.MatrixXd()
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Z = V.col(2)
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igl.slice(Z, b, bc)
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# Solve PDE
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solver = igl.eigen.SimplicialLLTsparse(-L_in_in)
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Z_in = solver.solve(L_in_b * bc)
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# slice into solution
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igl.slice_into(Z_in, vin, Z)
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# Alternative, short hand
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mqwf = igl.min_quad_with_fixed_data()
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# Linear term is 0
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B = igl.eigen.MatrixXd()
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B.setZero(V.rows(), 1)
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# Empty constraints
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Beq = igl.eigen.MatrixXd()
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Aeq = igl.eigen.SparseMatrixd()
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# Our cotmatrix is _negative_ definite, so flip sign
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igl.min_quad_with_fixed_precompute(-L, b, Aeq, True, mqwf)
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igl.min_quad_with_fixed_solve(mqwf, B, bc, Beq, Z)
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# Pseudo-color based on solution
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C = igl.eigen.MatrixXd()
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igl.jet(Z, True, C)
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# Plot the mesh with pseudocolors
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viewer = igl.viewer.Viewer()
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viewer.data.set_mesh(V, F)
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viewer.core.show_lines = False
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viewer.data.set_colors(C)
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viewer.launch()
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