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On Mon, 19 Mar 2012 19:24:33 +0100 Nicolas Pinto <nicolas.pinto@gmail.com> wrote:
Hello,
The following simple code hangs only when sparse has been imported:
``` from scipy import sparse # <<<<<<< BUG import numpy as np from scipy import linalg
N = 1000 np.random.seed(42) X = np.random.random((N, N)) print X.mean() v, Q = linalg.eigh(X) print v.mean() ```
Do you think this may be related to other arpack/umfpack/etc. known failures ?
Please let us know how can we help fix this issue.
Thanks for your help.
Regards,
Your matrix X is not symmetric.
X-X.T array([[ 0. , 0.76558138, 0.47028826, ..., 0.0515565 , 0.19001774, 0.33171462], [-0.76558138, 0. , 0.62596704, ..., -0.0230795 , -0.90677174, 0.12238354], [-0.47028826, -0.62596704, 0. , ..., -0.38459427, 0.28527075, 0.04568694], ..., [-0.0515565 , 0.0230795 , 0.38459427, ..., 0. , 0.57859577, -0.24268277], [-0.19001774, 0.90677174, -0.28527075, ..., -0.57859577, 0. , 0.52747713], [-0.33171462, -0.12238354, -0.04568694, ..., 0.24268277, -0.52747713, 0. ]])
eigh assumes a symmetric or hermitian matrix. Nils