[SciPy-Dev] ERROR: test_arpack.test_hermitian_modes

Pauli Virtanen pav@iki...
Sat Jun 18 20:54:51 CDT 2011


On Sat, 18 Jun 2011 23:42:44 +0200, Nils Wagner wrote:
> Thank you for very much for the extension to generalized eigenvalue
> problems.

You should thank Jake V. instead, I just merged his work.

[clip]
> ======================================================================
> ERROR: test_arpack.test_hermitian_modes(True, <gen-hermitian>, 'F', 2,
> 'SM', None, None, <function aslinearoperator at 0x2640a28>)
> ----------------------------------------------------------------------
[clip]
> ValueError: Error in inverting M: function gmres did not converge (info
> = 60).

Check that you have a working GMRES: try e.g.

import numpy as np
import scipy.sparse.linalg
A = np.random.rand(6, 6) + 1j*np.random.rand(6, 6)
b = np.random.rand(6) + 1j*np.random.rand(6)
x, info = scipy.sparse.linalg.gmres(A, b)
y = np.linalg.solve(A, b)
print abs(x - y).max()

I've noticed that at gfortran 4.5.2 miscompiles Scipy's gmres routine
with -O0.

> FAIL: test_arpack.test_hermitian_modes(True, <gen-hermitian>, 'D', 2,
> 'LM', None, None, <function aslinearoperator at 0x2640a28>)
> ----------------------------------------------------------------------

This one looks like a precision issue. Can you try increasing the
`1000` prefactor e.g. to `2000` for the _rtol and _atol values for
float64 in test_arpack.py, to see how large it needs to be for your 
system.



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