eigenfunctions.py

import igl
import numpy as np
import polyscope as ps
import scipy

# https://www.cs.cmu.edu/~kmcrane/Projects/ModelRepository/spot.zip
path = "/Users/cbabraham/data/mesh/spot/spot_triangulated.obj"
verts,faces = igl.read_triangle_mesh(path)

ps.init()
original = ps.register_surface_mesh("mesh", verts, faces)

L = igl.cotmatrix(verts, faces)
M = igl.massmatrix(verts, faces)

# eigendecomposition of the laplacian
eigenvals, eigenvecs = scipy.sparse.linalg.eigsh(L, 6, M)

for i, eigenvector in enumerate(eigenvecs.swapaxes(0,1)):
	original.add_scalar_quantity(
		"eigenvector-{}".format(i),
		eigenvector.astype(np.float32), # discard complex components
		defined_on='vertices'
	)

ps.show()

Not sure exactly what I was expecting but this doesn't seem right.