Programming Assignment 2

Yiming Liu (yimingl@princeton.edu)

Oct 29


Spectral Analysis

My program can also find the eigenvectors of the laplacian matrix. Since the cotangent laplacian matrix is not symmetric, for this feature I use the connectivity laplacian matrix instead.

I use the reverse communication interface of ARPACK++ to implement this feature.

Here I demonstrate the smallest non-zero eigenvectors of dragon, armadillo, and bunny meshes. We can observe that the eigenvectors with smallest eigenvalues encode low-frequency information, and eigenvectors with larger eigenvalues encode higher-frequency information.


Dragon

IndexEigenvector
1
2
3
4
5
7
14
18
122

Armadillo

IndexEigenvector
1
2
3
4
5
97
103

Bunny

IndexEigenvector
1
2
3
4
5
24
39