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
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]<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
