[petsc-users] why a certain option cannot be used

[Sun, Hui]

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:


 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
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