> On 9 Apr 2024, at 4:19 PM, Carl-Johan Thore <[email protected]> wrote: > > This Message Is From an External Sender > This message came from outside your organization. > Thanks for the suggestion. I don't have a factored matrix (and can't really > use direct linear solvers) so MatSolveTranspose doesn't seem to be an option. > I should have mentioned that I've also tried KSPSolveTranspose but that > doesn't work with pcredistribute
I’m not a frequent PCREDISTRIBUTE user, but it looks like https://urldefense.us/v3/__https://petsc.org/release/src/ksp/pc/impls/redistribute/redistribute.c.html*line332__;Iw!!G_uCfscf7eWS!bgGlN3dW5g5M98EkZPPaYivRkcXtawYE_jKsdMC0zK2bDy4u1Qy1KOMIcZ-_sBABRkHTzGlKHmAefb8Ozy3XbQ$ could be copy/paste’d into PCApplyTranspose_Redistribute() by just changing a MatMult() to MatMultTranspose() and KSPSolve() to KSPSolveTranspose(). Would you be willing to contribute (and test) this? Then, KSPSolveTranspose() — which should be the function you call — will work. Thanks, Pierre > /Carl-Johan > > On Tue, Apr 9, 2024 at 3:59 PM Zhang, Hong <[email protected] > <mailto:[email protected]>> wrote: >> Carl-Johan, >> You can use MatSolveTranspose() to solve A'*x = b. See >> petsc/src/ksp/ksp/tutorials/ex79.c >> >> `MatCreateTranspose()` is used if you only need a matrix that behaves like >> the transpose, but don't need the storage to be changed, i.e., A and A' >> share same matrix storage, thus MatGetRow() needs to get columns of A, which >> is not supported. >> >> Hong >> From: petsc-users <[email protected] >> <mailto:[email protected]>> on behalf of Carl-Johan Thore >> <[email protected] <mailto:[email protected]>> >> Sent: Tuesday, April 9, 2024 6:38 AM >> To: petsc-users <[email protected] <mailto:[email protected]>> >> Subject: [petsc-users] MatCreateTranspose >> >> This Message Is From an External Sender >> This message came from outside your organization. >> >> Hi, >> >> I have a matrix A with transpose A' and would like to solve the linear >> system A'*x = b using the pcredistribute preconditioner. It seemed like a >> good idea to use MatCreateTranspose, but this leads to >> >> [0]PETSC ERROR: --------------------- Error Message >> -------------------------------------------------------------- >> [0]PETSC ERROR: No support for this operation for this object type >> [0]PETSC ERROR: No method getrow for Mat of type transpose >> [0]PETSC ERROR: See >> https://urldefense.us/v3/__https://petsc.org/release/faq/__;!!G_uCfscf7eWS!bgGlN3dW5g5M98EkZPPaYivRkcXtawYE_jKsdMC0zK2bDy4u1Qy1KOMIcZ-_sBABRkHTzGlKHmAefb8Z27cesg$ >> >> <https://urldefense.us/v3/__https://petsc.org/release/faq/__;!!G_uCfscf7eWS!bVYrcPfbXSXCcthSH37OClTgnf7RxkizULEW1ZZJ5yYG3-50366x_OFSPmOgGWEcOeFyOmAMSFewAyCnxIUg7K8W_neRPw$> >> for trouble shooting. >> [0]PETSC ERROR: Petsc Release Version 3.21.0, unknown >> [0]PETSC ERROR: Configure options COPTFLAGS="-O3 -march=native" >> CXXOPTFLAGS="-O3 -march=native" --with-fortran-bindings=0 FOPTFLAGS="-O3 >> -march=native" CUDAOPTFLAGS=-O3 --with-cuda --with-cusp --with-debugging=0 >> --download-scalapack --download-hdf5 --download-zlib --download-mumps >> --download-parmetis --download-metis --download-ptscotch --download-hypre >> --download-spai >> [0]PETSC ERROR: #1 MatGetRow() at >> /mnt/c/mathware/petsc/petsc-v3-21-0/src/mat/interface/matrix.c:573 >> [0]PETSC ERROR: #2 PCSetUp_Redistribute() at >> /mnt/c/mathware/petsc/petsc-v3-21-0/src/ksp/pc/impls/redistribute/redistribute.c:111 >> [0]PETSC ERROR: #3 PCSetUp() at >> /mnt/c/mathware/petsc/petsc-v3-21-0/src/ksp/pc/interface/precon.c:1079 >> [0]PETSC ERROR: #4 KSPSetUp() at >> /mnt/c/mathware/petsc/petsc-v3-21-0/src/ksp/ksp/interface/itfunc.c:415 >> >> MatTranspose is a working alternative, but MatCreateTranspose would be >> preferable. In principle the solution seems straightforward -- just add a >> getrow method -- but is it, and is it a good idea (performancewise etc)? >> >> Kind regards, >> Carl-Johan
