Hi, Hong Thank you. If there is no bug for using PLAPACK for matrix-matrix multiplications, I will try :-) Thanks again.
Cheers Gao ________________________________ From: Hong Zhang [[email protected]] Sent: Thursday, April 05, 2012 5:39 PM To: Gao Bin Cc: PETSc users list Subject: Re: [petsc-users] question about MatMatMultTranspose Bin : Thank you! From Barry's email, I have learned that PETSc aims at sparse matrix. Therefore, I may consider using MatGetArray() for further parallel calculations, or using Elemental/PLAPACK for dense matrix calculations. I notice PETSc could use PLAPACK, but if I understand correctly, that has only been implemented for LU, Cholesky decomposition, not matrix-matrix multiplications (although it looks to be simple). We do have MatMatMult_MPIDense_MPIDense() in ~petsc/src/mat/impls/dense/mpi/mpidense.c. i.e., we tried to interface PLAPACK's dense matrix-matrix multiplication. However, in MatMatMultSymbolic_MPIDense_MPIDense(): SETERRQ(((PetscObject)A)->comm,PETSC_ERR_LIB,"Due to apparent bugs in PLAPACK,this is not currently supported"); Therefore, this does not work. As regards my question, I am sorry that I need C_seqdense = A_seqdense*B_seqdense^T C_seqdense = A_seqdense^T*B_seqdense These are purely dense computation, Elemental/PLAPACK should be used. Hong Gao ________________________________ From: Hong Zhang [hzhang at mcs.anl.gov<mailto:[email protected]>] Sent: Thursday, April 05, 2012 4:30 PM To: Gao Bin Cc: PETSc users list Subject: Re: [petsc-users] question about MatMatMultTranspose Bin : We do not have plan for supporting parallel (mpiaij format) C = A*B^T because sparse inner product is too expensive, and we have parallel C = A^T*B. For sequential C = A*B^T, currently we only support C_seqaij = A_seqaij*B_seqaij^T Do you want C_seqdense = A_seqaij*B_seqaij^T or C_seqdense = A_seqaij*B_seqdense^T? Hong Good to know it is simpler ;-) I am switching to the developed version and try it. Again, thank you very much. P.S., Moreover, I notice that some functions is not for MATMPIDENSE. May I ask if they are too difficult to implement (for instance, C=A*B^T and C=A^T*B for MATMPIDENSE)? Thank you. Cheers Gao ________________________________ From: petsc-users-bounces at mcs.anl.gov<mailto:petsc-users-bounces at mcs.anl.gov> [petsc-users-bounces at mcs.anl.gov<mailto:petsc-users-bounces at mcs.anl.gov>] on behalf of Jed Brown [jedbrown at mcs.anl.gov<mailto:[email protected]>] Sent: Thursday, April 05, 2012 2:32 PM To: PETSc users list; Hong Zhang Subject: Re: [petsc-users] question about MatMatMultTranspose On Thu, Apr 5, 2012 at 05:16, Gao Bin <bin.gao at uit.no<mailto:bin.gao at uit.no>> wrote: Thank you for your quick reply. But as pointed out at http://www.mcs.anl.gov/petsc/petsc-dev/docs/manualpages/Mat/MatMatTransposeMult.html: This routine is currently only implemented for pairs of SeqAIJ matrices. C will be of type MATSEQAIJ. Therefore I can not use it for dense matrix, am I right? If so, will MatMatTransposeMult be extended for other types of matrix later on? Thank you very much. This is much simpler than the sparse case. Hong, did you intend to get around to this? -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20120405/83f9c67f/attachment.htm>
