[Numpy-discussion] Eigenvalues did not converge

Rick Muller rpmuller@gmail....
Mon Aug 29 09:56:31 CDT 2011

I'm bumping into the old "Eigenvalues did not converge" error using
numpy.linalg.eigh() on several different linux builds of numpy (1.4.1). The
matrix is 166x166. I can compute the eigenvalues on a Macintosh build of
numpy, and I can confirm that there aren't degenerate eigenvalues, and that
the matrix appears to be negative definite.

I've seen this before (though not for several years), and what I normally do
is to build lapack with -O0. This trick did not work in the current
instance. Does anyone have any tricks to getting eigh to work?

Other weird things that I've noticed about this case: I can compute the
eigenvalues using eigvals and eigvalsh, and can compute the eigenvals/vecs
using eig(). The matrix is real symmetric, and I've tested that it's
symmetric enough by forcibly symmetrizing it.

Thanks in advance for any help you can offer.

Rick Muller
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