1 2 static char help[] = "Tests MatCreateSubMatrices().\n\n"; 3 4 #include <petscmat.h> 5 6 int main(int argc,char **args) 7 { 8 Mat A,B,*Bsub; 9 PetscInt i,j,m = 6,n = 6,N = 36,Ii,J; 10 PetscErrorCode ierr; 11 PetscScalar v; 12 IS isrow; 13 14 ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr; 15 CHKERRQ(MatCreateSeqAIJ(PETSC_COMM_WORLD,N,N,5,NULL,&A)); 16 for (i=0; i<m; i++) { 17 for (j=0; j<n; j++) { 18 v = -1.0; Ii = j + n*i; 19 if (i>0) {J = Ii - n; CHKERRQ(MatSetValues(A,1,&Ii,1,&J,&v,INSERT_VALUES));} 20 if (i<m-1) {J = Ii + n; CHKERRQ(MatSetValues(A,1,&Ii,1,&J,&v,INSERT_VALUES));} 21 if (j>0) {J = Ii - 1; CHKERRQ(MatSetValues(A,1,&Ii,1,&J,&v,INSERT_VALUES));} 22 if (j<n-1) {J = Ii + 1; CHKERRQ(MatSetValues(A,1,&Ii,1,&J,&v,INSERT_VALUES));} 23 v = 4.0; CHKERRQ(MatSetValues(A,1,&Ii,1,&Ii,&v,INSERT_VALUES)); 24 } 25 } 26 CHKERRQ(MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY)); 27 CHKERRQ(MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY)); 28 CHKERRQ(MatView(A,PETSC_VIEWER_STDOUT_SELF)); 29 30 /* take the first diagonal block */ 31 CHKERRQ(ISCreateStride(PETSC_COMM_WORLD,m,0,1,&isrow)); 32 CHKERRQ(MatCreateSubMatrices(A,1,&isrow,&isrow,MAT_INITIAL_MATRIX,&Bsub)); 33 B = *Bsub; 34 CHKERRQ(ISDestroy(&isrow)); 35 CHKERRQ(MatView(B,PETSC_VIEWER_STDOUT_SELF)); 36 CHKERRQ(MatDestroySubMatrices(1,&Bsub)); 37 38 /* take a strided block */ 39 CHKERRQ(ISCreateStride(PETSC_COMM_WORLD,m,0,2,&isrow)); 40 CHKERRQ(MatCreateSubMatrices(A,1,&isrow,&isrow,MAT_INITIAL_MATRIX,&Bsub)); 41 B = *Bsub; 42 CHKERRQ(ISDestroy(&isrow)); 43 CHKERRQ(MatView(B,PETSC_VIEWER_STDOUT_SELF)); 44 CHKERRQ(MatDestroySubMatrices(1,&Bsub)); 45 46 /* take the last block */ 47 CHKERRQ(ISCreateStride(PETSC_COMM_WORLD,m,N-m-1,1,&isrow)); 48 CHKERRQ(MatCreateSubMatrices(A,1,&isrow,&isrow,MAT_INITIAL_MATRIX,&Bsub)); 49 B = *Bsub; 50 CHKERRQ(ISDestroy(&isrow)); 51 CHKERRQ(MatView(B,PETSC_VIEWER_STDOUT_SELF)); 52 53 CHKERRQ(MatDestroySubMatrices(1,&Bsub)); 54 CHKERRQ(MatDestroy(&A)); 55 56 ierr = PetscFinalize(); 57 return ierr; 58 } 59 60 /*TEST 61 62 test: 63 64 TEST*/ 65