[SciPy-User] Problems using scipy.sparse.linalg.eigs

Michael Dzjaparidze m_dzjaparidze@hotmail....
Mon Oct 8 10:18:31 CDT 2012

I'm having trouble using scipy.sparse.linalg.eigs in that it fails to find any eigenvalues hence raising a "DNAUPD  did not find any eigenvalues to sufficient accuracy." error. Even after experimenting with different tol parameter settings. If instead I use scipy.linalg.eig after first calling .todense() on my sparse matrix I do get all the eigenvalues I expect to get back. I suppose I could just do this, but that seems a bit inelegant after all the trouble of working with sparse matrices.

I realize this issue is a bit hard to answer if I don't provide a concrete example so quickly, but I just was wondering if anybody has experienced a similar problem perhaps? The eigenvalues which I expect to get back are N/2 complex conjugate pairs, where NxN is the size of my original matrix.

Any help or advice is greatly appreciated.
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