Thank you Matt. I've corrected it to
./ex70 -nx 32 -ny 48 -fieldsplit_1_pc_type jacobi However the output is still: residual u = 2.6315e-05 residual p = 0.000229872 residual [u,p] = 0.000231373 discretization error u = 0.00633503 discretization error p = 0.121534 discretization error [u,p] = 0.121699 WARNING! There are options you set that were not used! WARNING! could be spelling mistake, etc! Option left: name:-fieldsplit_1_pc_type value: jacobi If I type ./ex70 -help | grep fieldsplit_1_ the output is that nothing coming out. ________________________________ From: Matthew Knepley [[email protected]] Sent: Wednesday, July 16, 2014 2:32 PM To: Sun, Hui Cc: [email protected] Subject: Re: [petsc-users] why a certain option cannot be used On Wed, Jul 16, 2014 at 4:25 PM, Matthew Knepley <[email protected]<mailto:[email protected]>> wrote: On Wed, Jul 16, 2014 at 4:22 PM, Sun, Hui <[email protected]<mailto:[email protected]>> wrote: Thank you Matt for answering, however even with that I don't think it works. For example, the command ./ex70 -nx 32 -ny 48 -fieldsplit_1_type jacobi You have mistyped. Look carefully at my last message: -fieldsplit_1_pc_type jacobi I also want to note that you can see all the available options with -help. It does produce a lot of output, but you can segregate it by prefix ("fieldsplit_1_"). You can also see the prefix of each solver component using -ksp_view. Matt Matt gives me the following output residual u = 2.6315e-05 residual p = 0.000229872 residual [u,p] = 0.000231373 discretization error u = 0.00633503 discretization error p = 0.121534 discretization error [u,p] = 0.121699 WARNING! There are options you set that were not used! WARNING! could be spelling mistake, etc! Option left: name:-fieldsplit_1_type value: jacobi Furthermore, if I look into the possible options with keyword fieldsplit involved by the command: ./ex70 -help | grep -A5 fieldsplit I get this output: eisenstat ilu icc cholesky asm gasm ksp composite redundant nn mat fieldsplit galerkin exotic hmpi asa cp lsc redistribute svd gamg tfs (PCSetType) -pc_use_amat: <FALSE> use Amat (instead of Pmat) to define preconditioner in nested inner solves (PCSetUseAmat) Krylov Method (KSP) options ------------------------------------------------- -ksp_type <gmres>: Krylov method (one of) cg groppcg pipecg cgne nash stcg gltr richardson chebyshev gmres tcqmr bcgs ibcgs fbcgs fbcgsr bcgsl cgs tfqmr cr pipecr lsqr preonly qcg bicg fgmres minres symmlq lgmres lcd gcr pgmres specest dgmres (KSPSetType) -ksp_max_it <10000>: Maximum number of iterations (KSPSetTolerances) So I don't see any option that's similar to -fieldsplit_1_type. Hui ________________________________ From: Matthew Knepley [[email protected]<mailto:[email protected]>] Sent: Wednesday, July 16, 2014 2:16 PM To: Sun, Hui Cc: [email protected]<mailto:[email protected]> Subject: Re: [petsc-users] why a certain option cannot be used On Wed, Jul 16, 2014 at 4:09 PM, Sun, Hui <[email protected]<mailto:[email protected]>> wrote: I want to solve Stokes equation using user defined schur complement preconditioner. So I'm reading and testing snes/examples/tutorial/ex55.c, and ex70.c. In these examples, there are comments about the usage, for example: mpiexec -n 2 ./stokes -nx 32 -ny 48 -fieldsplit_1_user_pc. However the option -fieldsplit_1_user_pc is not recognized by the executable. The output of the above command is: This ("user_pc") is just a mnemonic. What it means is that you can use any PC in this slot. What he should have written is -fieldsplit_1_pc_type <user pc> Thanks, Matt residual u = 2.6315e-05 residual p = 0.000229872 residual [u,p] = 0.000231373 discretization error u = 0.00633503 discretization error p = 0.121534 discretization error [u,p] = 0.121699 WARNING! There are options you set that were not used! WARNING! could be spelling mistake, etc! Option left: name:-fieldsplit_1_user_pc (no value) I'm wondering what's going on. Is that because I need some specific options during my configuring of the package? By the way, the version of PETSc I'm using is 3.4.4. Best, Hui -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener
