On Wed, Jul 16, 2014 at 4:25 PM, Matthew Knepley <[email protected]> wrote:
> On Wed, Jul 16, 2014 at 4:22 PM, Sun, Hui <[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]] >> *Sent:* Wednesday, July 16, 2014 2:16 PM >> *To:* Sun, Hui >> *Cc:* [email protected] >> *Subject:* Re: [petsc-users] why a certain option cannot be used >> >> On Wed, Jul 16, 2014 at 4:09 PM, Sun, Hui <[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
