> Il giorno 20 lug 2018, alle ore 19:58, Smith, Barry F. <bsm...@mcs.anl.gov>
> ha scritto:
>
>
>
>> On Jul 20, 2018, at 7:01 AM, Pierpaolo Minelli <pierpaolo.mine...@cnr.it>
>> wrote:
>>
>> Hi,
>>
>> in my code I have to solve both a system in the field of real numbers and in
>> the field of complex numbers.
>> My approach has been as follows.
>> First I configured PETSc with the --with-scalar-type=complex option.
>> Using this option I have unfortunately lost the possibility to use the two
>> preconditioners ML and Hypre.
>
> You should still be able to use the PETSc PCGAMG algebraic multigrid
> solver. Have you tried that? If there are issues let us know because we would
> like to continue to improve the performance of PCGAMG to get it to be closer
> to as good as ML and hypre.
>
> Barry
>
I will try to convert, as suggested by Matthew, my complex system in a system
twice as large in real numbers. When i finish, i will try to use ML, Hypre and
GAMG and i let you know if there are any performance differences.
Thanks
Pierpaolo
>> I later created two subspaces of Krylov and tried to solve the two systems
>> as I used to when solving the only equation in the real numbers field.
>> In order to correctly solve the system in the field of real numbers I had to
>> transform the coefficients from real to complex with an imaginary part equal
>> to zero.
>>
>> Is there a possibility to use a different and better approach to solve my
>> problem?
>>
>> Perhaps an approach where you can continue to use ML and Hypre for system
>> solving in the real numbers field or where you don't need to use complex
>> numbers when real numbers would actually suffice?
>>
>> Thanks in advance
>>
>> Pierpaolo
>>
>
