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igl/python/tutorial/306_EigenDecomposition.py
T
2018-11-28 08:29:23 -05:00

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#!/usr/bin/env python
#
# This file is part of libigl, a simple c++ geometry processing library.
#
# Copyright (C) 2017 Sebastian Koch <s.koch@tu-berlin.de> and Daniele Panozzo <daniele.panozzo@gmail.com>
#
# This Source Code Form is subject to the terms of the Mozilla Public License
# v. 2.0. If a copy of the MPL was not distributed with this file, You can
# obtain one at http://mozilla.org/MPL/2.0/.
import sys, os
# Add the igl library to the modules search path
sys.path.insert(0, os.getcwd() + "/../")
import pyigl as igl
from shared import TUTORIAL_SHARED_PATH, check_dependencies
dependencies = ["glfw"]
check_dependencies(dependencies)
V = igl.eigen.MatrixXd()
U = igl.eigen.MatrixXd()
F = igl.eigen.MatrixXi()
c = 0
bbd = 1.0
twod = False
if not igl.read_triangle_mesh(TUTORIAL_SHARED_PATH + "beetle.off", V, F):
print("failed to load mesh")
twod = V.col(2).minCoeff() == V.col(2).maxCoeff()
bbd = (V.colwiseMaxCoeff() - V.colwiseMinCoeff()).norm()
L = igl.eigen.SparseMatrixd()
M = igl.eigen.SparseMatrixd()
igl.cotmatrix(V, F, L)
L = -L
igl.massmatrix(V, F, igl.MASSMATRIX_TYPE_DEFAULT, M)
k = 5
D = igl.eigen.MatrixXd()
if not igl.eigs(L, M, k + 1, igl.EIGS_TYPE_SM, U, D):
print("Eigs failed.")
U = (U - U.minCoeff()) / (U.maxCoeff() - U.minCoeff())
viewer = igl.glfw.Viewer()
def key_down(viewer, key, mod):
global U, c
if key == ord(' '):
U = U.rightCols(k)
# Rescale eigen vectors for visualization
Z = bbd * 0.5 * U.col(c)
C = igl.eigen.MatrixXd()
igl.parula(U.col(c), False, C)
c = (c + 1) % U.cols()
if twod:
V.setcol(2, Z)
viewer.data().set_mesh(V, F)
viewer.data().compute_normals()
viewer.data().set_colors(C)
return True
return False
viewer.callback_key_down = key_down
viewer.callback_key_down(viewer, ord(' '), 0)
viewer.data().show_lines = False
viewer.launch()