Thanks. I get it.
>? 2012-10-31 21:24:03?"Hong Zhang" <hzhang at mcs.anl.gov> ???
>Jim,
>> In my view, the intent of parallel computing is sovling large system. As
>> you said, MUMPS is mainly used in
>" the intent" does not automatically become the reality.
>All parallel direct solvers are intended to solve ill-conditioned problems as
>large as possible.
>But the algorithms (full matrix factorization) consume large memories and
>inter-processor
>communications. Unless your matrix has special data structure, the direct
>solvers cannot be scalable
>in general.
>>small problems. So are they contradictory. Or, is the "Small problems and
>>moderate-size 2D problems" just relative,
>>compared with the large system?
>Yes.
>Hong
>>At 2012-10-30 23:47:59,"Jed Brown" <jedbrown at mcs.anl.gov> wrote:
>>Simple: it's better when it's faster. Small problems and moderate-size 2D
>>problems often work well with direct solvers.
>>On Oct 30, 2012 8:29 AM, "w_ang_temp" <w_ang_temp at 163.com> wrote:
>>Hello,
>>As is know, MUMPS is based on a direct method. When the system is big,
the parallel direct solver is
>>not effective compared with the iterative solver. So when is it better to use
>>MUMPS?
>> Thanks.
>> Jim
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