[petsc-users] Large Matrix eigenvalue problem : configuration

[venkatesh g]

Thank you. So the single eigenvector's size which is Nx1 is the number of
unknowns and should be less than 2^31-1 so as to avoid configuring with
'--with-64-bit-indices=1' ??


On Sat, May 16, 2015 at 8:05 PM, Matthew Knepley <knepley at gmail.com> wrote:

> On Sat, May 16, 2015 at 3:49 AM, venkatesh g <venkateshgk.j at gmail.com>
> wrote:
>
>> Hi,
>>
>> I am trying to solving AX=lambda BX
>>
>> A and B are of size 57000 x 57000
>>
>> Currently I solve my small matrices using -st_type sinvert and -eps_nev 1
>>
>> So I get 1 eigenvalue and eigenvector.
>>
>> So for the 57000x57000 large matrix problem, the unknown eigenvector is
>> 57000x1
>>
>> Should I configure the petsc as '--with-64-bit-indices=1' for this
>> problem ?
>>
>
> It is not necessary.
>
>    Matt
>
>
>> Is the unknowns being considered as the entire eigenspace 57000x57000 ?
>>
>> kindly let me know.
>>
>> Venkatesh
>>
>
>
>
> --
> What most experimenters take for granted before they begin their
> experiments is infinitely more interesting than any results to which their
> experiments lead.
> -- Norbert Wiener
>
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