Output of SCALAPACK pdgetrf as input for LAPACK dgesv

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Output of SCALAPACK pdgetrf as input for LAPACK dgesv

Postby hpcdkhab » Wed Apr 11, 2018 10:15 am

Dear all,
I try to use the output of the SCALAPACK routine pdgetrf (LU factorization) as input for the LAPACK routine dgesv.
In the first phase the factorization is done with several MPI processes (pdgetrf).
In the second phase, the distributed matrix is gathered to process 0 (pdgeadd).
In the third phase, the linear system is solved on the process 0 (dgesv).

My question is about the second phase: How to gather the pivoting information ?
Here is a pseudocode:
Code: Select all
//LU Decomposition
pdgetrf_(&rowsGlobal,&colsGlobal,ADistr,&i_one,&i_one,descADistr,IPIV,&Ret);
//Gather Matrix to proc 0
pdgeadd_("N",&rowsGlobal, &colsGlobal, &one, ADistr,&i_one, &i_one, itsDescADistr, &zero, AResult, &i_one, &i_one, itsDescAResult);
//Gather IPIV to IPIV0
???????
MPI_Barrier(MPI_COMM_WORLD);
//Solve the linear system on proc 0
if(my_rank==0)
  dgesv_(&rowsGlobal, &i_one, AResult, &rowsGlobal, &IPIV0, b, &rowsGlobal, &Ret);

Thank you,
Dmirtry
hpcdkhab
 
Posts: 2
Joined: Wed Apr 11, 2018 7:44 am

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