1 2 static char help[] = "Tests automatic allocation of matrix storage space.\n\n"; 3 4 #include <petscmat.h> 5 6 int main(int argc,char **args) 7 { 8 Mat C; 9 PetscInt i,j,m = 3,n = 3,Ii,J; 10 PetscScalar v; 11 MatInfo info; 12 13 PetscCall(PetscInitialize(&argc,&args,(char*)0,help)); 14 PetscCall(PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL)); 15 PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL)); 16 17 /* create the matrix for the five point stencil, YET AGAIN */ 18 PetscCall(MatCreate(PETSC_COMM_SELF,&C)); 19 PetscCall(MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n)); 20 PetscCall(MatSetFromOptions(C)); 21 PetscCall(MatSetUp(C)); 22 for (i=0; i<m; i++) { 23 for (j=0; j<n; j++) { 24 v = -1.0; Ii = j + n*i; 25 if (i>0) {J=Ii-n; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));} 26 if (i<m-1) {J=Ii+n; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));} 27 if (j>0) {J=Ii-1; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));} 28 if (j<n-1) {J=Ii+1; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));} 29 v = 4.0; PetscCall(MatSetValues(C,1,&Ii,1,&Ii,&v,INSERT_VALUES)); 30 } 31 } 32 PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY)); 33 PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY)); 34 PetscCall(MatView(C,PETSC_VIEWER_STDOUT_SELF)); 35 36 PetscCall(MatGetInfo(C,MAT_LOCAL,&info)); 37 PetscCall(PetscPrintf(PETSC_COMM_SELF,"matrix nonzeros = %" PetscInt_FMT ", allocated nonzeros = %" PetscInt_FMT "\n",(PetscInt)info.nz_used,(PetscInt)info.nz_allocated)); 38 39 PetscCall(MatDestroy(&C)); 40 PetscCall(PetscFinalize()); 41 return 0; 42 } 43 44 /*TEST 45 46 test: 47 48 TEST*/ 49