[petsc-users] MatFDColorCreate takes really big portion of the total time

[Barry Smith]

   Parallel or sequential? 

   Barry

Please send entire -log_summary output

On Jun 26, 2012, at 2:22 PM, Bao Kai wrote:

> Hi, all,
> 
> I use the SNES in petsc-3.2 to solve my problem. The problem is a 3-D
> finite difference problem with structured grid.
> 
> I use MatFDColorCreate to generate the Jacobian matrix. I just found
> that when the size of problem is big, MatFDColorCreate takes really
> long time.  The following results is the summary with size of the mesh
> to be 1000^3. 90% of the time is costed in MatFDColorCreate.
> 
>    237 MatGetOrdering         1 1.0 1.3502e-03 1.1 0.00e+00 0.0
> 0.0e+00 0.0e+00 2.0e+00  0  0  0  0  0   0  0  0  0  0     0
>    238 MatZeroEntries        39 1.0 9.2822e-02 1.2 0.00e+00 0.0
> 0.0e+00 0.0e+00 0.0e+00  0  0  0  0  0   0  0  0  0  0     0
>    239 MatFDColorCreate      10 1.0 3.2863e+03 1.0 0.00e+00 0.0
> 1.6e+07 5.0e+02 6.8e+02 90  0  0  0  3  90  0  0  0  3     0
>    240 MatFDColorApply       20 1.0 2.5288e+01 1.0 3.54e+07 1.1
> 4.6e+08 2.0e+03 8.0e+01  1  0  5  5  0   1  0  5  5  0 42708
>    241 MatFDColorFunc       560 1.0 9.5386e+00 1.3 0.00e+00 0.0
> 4.5e+08 2.0e+03 0.0e+00  0  0  5  5  0   0  0  5  5  0     0
> 
> And the following the code I use.
> 
>    262        call DMGetMatrix(solv%da, MATAIJ, solv%jac,ierr)
>    263        call
> DMGetColoring(solv%da,IS_COLORING_GLOBAL,MATAIJ,iscoloring,ierr)
>    264        call MatFDColoringCreate(solv%jac,iscoloring,matfdcoloring,ierr)
>    265        call
> MatFDColoringSetFunction(matfdcoloring,FormFunction,equ,ierr)
>    266        call MatFDColoringSetFromOptions(matfdcoloring,ierr)
>    267        call SNESSetJacobian(solv%snes, solv%jac,
> solv%jac,SNESDefaultComputeJacobianColor, matfdcoloring, ierr)
>    268        call ISColoringDestroy(iscoloring,ierr)
> 
> I am wondering if there is anything I can do to improve this problem.
> 
> Thank you very much.
> 
> Best Regards,
> Kai