[petsc-users] MATELEMENTAL strange behaviour

[Hong]

Bernard,
The bug is fixed in branch hzhang/fix-elementalSetOption.
https://bitbucket.org/petsc/petsc/commits/891a05710665f381fc66132810d0b09973b0e049

It will be merged to petsc-release after night tests.
Thanks for reporting it!

Hong

On Wed, Sep 28, 2016 at 8:04 PM, Hong <hzhang at mcs.anl.gov> wrote:

> Bernard:
> With your code, I reproduced error and found that the default
> MAT_ROW_ORIENTED for MatSetValues() is changed to MAT_COLUMN_ORIENTED.
> This is a bug in our library. I'll fix it.
>
> You can add
> MatSetOption(C,MAT_ROW_ORIENTED,PETSC_TRUE);
> before 2nd call of matrixC(C,t).
>
> Thanks for reporting the bug.
>
> Hong
>
> Hello,
>>
>> Here is a trimmed down piece of code that illustrates a strange behaviour
>> that I am desperately trying to understand.
>>
>> The problem is that I would expect successive calls to MatView(C,…) to
>> display the same numbers. However, the numbers displayed are different,
>> even though the content of the matrix C should be the same.
>>
>> Any help to resolve this would be appreciated.
>>
>> Cheers,
>> Bernard.
>>
>> Code:
>> ******
>>
>> static char help[] = "Elemental test\n\n";
>>
>> /*T
>>
>> T*/
>>
>> #include <petscmat.h>
>>
>> PetscScalar pi=3.141592653589793;
>>
>> /* Prototypes */
>> PetscErrorCode matrixC(Mat C, PetscScalar t);
>>
>> #undef __FUNCT__
>> #define __FUNCT__ "main"
>> int main(int argc, char **args){
>>
>>    Mat C;
>>
>>    PetscInt N = 8;
>>    PetscScalar t=0.1, dt=0.0001;
>>    PetscErrorCode ierr;
>>
>>    /* parameters */
>>    ierr = PetscInitialize(&argc, &args, (char*) 0, help) ;CHKERRQ(ierr);
>>
>>    ierr = MatCreate(PETSC_COMM_WORLD, &C); CHKERRQ(ierr);
>>    ierr = MatSetSizes(C, PETSC_DECIDE, PETSC_DECIDE, N, N); CHKERRQ(ierr);
>>    ierr = MatSetType(C, MATELEMENTAL); CHKERRQ(ierr);
>>    ierr = MatSetFromOptions(C); CHKERRQ(ierr);
>>    ierr = MatSetUp(C); CHKERRQ(ierr);
>>
>>    ierr=matrixC(C,t);
>>    ierr = MatView(C,PETSC_VIEWER_STDOUT_WORLD);
>>
>>    ierr=matrixC(C,t);
>>    ierr = MatView(C,PETSC_VIEWER_STDOUT_WORLD);
>>
>>    ierr = MatDestroy(&C);CHKERRQ(ierr);
>>
>>    ierr = PetscFinalize();
>>
>>    return ierr;
>> }
>>
>> /* Matrix C*/
>> PetscErrorCode matrixC(Mat C, PetscScalar t){
>>
>>    PetscErrorCode ierr;
>>    IS isrows,iscols;
>>    const PetscInt *rows,*cols;
>>    PetscScalar    *v;
>>    PetscInt i,j,nrows,ncols;
>>    PetscInt n,m;
>>
>>    /* Set local matrix entries */
>>    ierr = MatGetOwnershipIS(C,&isrows,&iscols);CHKERRQ(ierr);
>>    ierr = ISGetLocalSize(isrows,&nrows);CHKERRQ(ierr);
>>    ierr = ISGetIndices(isrows,&rows);CHKERRQ(ierr);
>>    ierr = ISGetLocalSize(iscols,&ncols);CHKERRQ(ierr);
>>    ierr = ISGetIndices(iscols,&cols);CHKERRQ(ierr);
>>    ierr = PetscMalloc1(nrows*ncols,&v);CHKERRQ(ierr);
>>
>>    for (i=0; i<nrows; i++) {
>>       n=rows[i];
>>       for (j=0; j<ncols; j++) {
>>          m=cols[j];
>>          v[i*ncols+j] = -0.5*(exp(-(m+n+1.5)*(m+n+1.5)
>> *pi*pi*t)-exp(-(m-n+0.5)*(m-n+0.5)*pi*pi*t));
>>       }
>>    }
>>
>>    ierr = MatSetValues(C,nrows,rows,ncols,cols,v,INSERT_VALUES);CHKERR
>> Q(ierr);
>>    ierr = MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
>>    ierr = MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
>>    ierr = ISRestoreIndices(isrows,&rows);CHKERRQ(ierr);
>>    ierr = ISRestoreIndices(iscols,&cols);CHKERRQ(ierr);
>>    ierr = ISDestroy(&isrows);CHKERRQ(ierr);
>>    ierr = ISDestroy(&iscols);CHKERRQ(ierr);
>>    ierr = PetscFree(v);CHKERRQ(ierr);
>>
>>     PetscFunctionReturn(0);
>> }
>>
>> Output:
>> ********
>>
>> mpirun -n 2 ./elemental
>>
>> Mat Object: 2 MPI processes
>>   type: elemental
>> Elemental matrix (cyclic ordering)
>> 0.336403 2.8059e-06 0.0532215 1.04511e-09 0.00104438
>> 0.00104718 0.390672 0.0542687 0.0542687 0.390672
>> 0.389625 0.00104718 0.390669 2.80695e-06 0.0542687
>> 2.80695e-06 0.390672 0.00104718 0.390672 0.0542687
>> 0.0542659 0.0542687 0.390672 0.00104718 0.390672
>>
>> Elemental matrix (explicit ordering)
>>   Mat Object: 2 MPI processes
>>     type: mpidense
>> 3.3640319378153799e-01 5.3221486768492490e-02 1.0443777750910219e-03
>> 2.8059034408741489e-06 1.0451056906250189e-09
>> 3.8962468055003047e-01 3.9066905832512150e-01 5.4268670447024388e-02
>> 1.0471847236375868e-03 2.8069486006233780e-06
>> 5.4265864543583515e-02 3.9067186422856237e-01 3.9067186527366804e-01
>> 5.4268671492184138e-02 1.0471847236916457e-03
>> 1.0471836785318962e-03 5.4268671492130077e-02 3.9067186527372211e-01
>> 3.9067186527372211e-01 5.4268671492184138e-02
>> 2.8069485465647739e-06 1.0471847236916453e-03 5.4268671492184138e-02
>> 3.9067186527372211e-01 3.9067186527372211e-01
>> Mat Object: 2 MPI processes
>>   type: elemental
>> Elemental matrix (cyclic ordering)
>> 0.336403 2.8059e-06 0.390672 2.80695e-06 0.00104718
>> 0.0532215 1.04511e-09 0.389625 0.390672 0.0542687
>> 0.00104438 0.390672 0.390669 0.390672 0.0542659
>> 0.00104718 0.0542687 0.0542687 0.0542687 0.390672
>> 0.0542687 0.00104718 2.80695e-06 0.00104718 0.390672
>>
>> Elemental matrix (explicit ordering)
>>   Mat Object: 2 MPI processes
>>     type: mpidense
>> 3.3640319378153799e-01 3.9067186527372211e-01 1.0471847236916453e-03
>> 2.8059034408741489e-06 2.8069486006233780e-06
>> 1.0443777750910219e-03 3.9066905832512150e-01 5.4265864543583515e-02
>> 3.9067186527372211e-01 3.9067186527372211e-01
>> 5.4268671492130077e-02 2.8069485465647739e-06 3.9067186527366804e-01
>> 1.0471847236375868e-03 1.0471847236916457e-03
>> 5.3221486768492490e-02 3.8962468055003047e-01 5.4268671492184138e-02
>> 1.0451056906250189e-09 3.9067186527372211e-01
>> 1.0471836785318962e-03 5.4268670447024388e-02 3.9067186422856237e-01
>> 5.4268671492184138e-02 5.4268671492184138e-02
>>
>>
>>
>>
>
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