[petsc-users] A very strange bug about using multiple KSPs

[Dave May]

Try moving your print statement in ComputeMatrix2 to be after
PetscFunctionBeginUser;

You should really use a debugger to see if these functions are being called
or not - don't use print statements.

On Tuesday, 3 March 2015, Sun, Hui <hus003 at ucsd.edu> wrote:

>  I set up 2 KSPs through KSPSetComputeOperators, with separate compute
> matrix functions.
>
>
>
>     ierr = KSPSetComputeOperators(ksp1,ComputeMatrix1,NULL);CHKERRQ(ierr);
>
>     ierr = KSPSetComputeOperators(ksp2,ComputeMatrix2,NULL);CHKERRQ(ierr);
>
>  Within each computeMatrix function, I define the matrix, and I also
> print something to the screen. So
>
>   PetscErrorCode ComputeMatrix1(KSP ksp, Mat J,Mat jac, void *ctx)
>
> {
>
>     ......
>
>     ierr    = PetscPrintf(PETSC_COMM_WORLD,"1\n");CHKERRQ(ierr);
>
>     ......
>
> }
>
>
>  PetscErrorCode ComputeMatrix2(KSP ksp, Mat J,Mat jac, void *ctx)
>
> {
>
>     ......
>
>     ierr    = PetscPrintf(PETSC_COMM_WORLD,"2\n");CHKERRQ(ierr);
>
>     ......
>
> }
>
>
>  Now if I compile and execute the code, it only print 2, completely
> ignoring 1, which is not expected, since I have setup ksp1 to use
> ComputeMatrix1.
>
>  Does anyone know what might be wrong? Thank you. I have attached the
> short code here in this email as well.
>
>  Hui
>
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