[SciPy-Dev] ERROR: test_arpack.test_hermitian_modes

[Nils Wagner]

On Sun, 19 Jun 2011 12:56:53 +0000 (UTC)
  Pauli Virtanen <pav at iki.fi> wrote:
> On Sun, 19 Jun 2011 10:10:52 +0200, Nils Wagner wrote:
> [clip]
>>>> FAIL: test_arpack.test_hermitian_modes(True,
>>>><gen-hermitian>, 'D', 2,
>>>> 'LM', None, None, <function aslinearoperator at
>>>>0x2640a28>)
> [clip]
>> The problem persists if I increase the prefactor to 
>>2000. i.e.
>>
>> ======================================================================
>> ERROR: test_arpack.test_hermitian_modes(True, 
>><gen-hermitian>, 'F', 2,
>> 'SM', None, None, <function aslinearoperator at 
>>0xe12e60>)
>> ----------------------------------------------------------------------
> [clip]
>> ValueError: Error in inverting M: function gmres did not 
>>converge (info
>> = 60)
> 
> This is  different problem: Does the ..., 
><gen-hermitian>, 'D', ...
> one vanish when the prefactor is 2000? If not, how large 
>a prefactor
> is large enough?
> 

Oops, I missed that. It works for me, if the prefactor is 
2000.
Hence, gmres is inaccurate.

Nils