1 2 static char help[] = "Tests MATCENTERING matrix type.\n\n"; 3 4 #include <petscmat.h> 5 6 int main(int argc,char **argv) 7 { 8 PetscErrorCode ierr; 9 PetscInt n; 10 Mat C; 11 Vec x,y; 12 PetscReal norm; 13 PetscMPIInt size; 14 15 ierr = PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr; 16 CHKERRMPI(MPI_Comm_size(PETSC_COMM_WORLD,&size)); 17 18 /* Create a parallel vector with 10*size total entries, and fill it with 1s. */ 19 n = 10*size; 20 CHKERRQ(VecCreate(PETSC_COMM_WORLD,&x)); 21 CHKERRQ(VecSetSizes(x,PETSC_DECIDE,n)); 22 CHKERRQ(VecSetFromOptions(x)); 23 CHKERRQ(VecSet(x,1.0)); 24 25 /* Create a corresponding n x n centering matrix and use it to create a mean-centered y = C * x. */ 26 CHKERRQ(VecDuplicate(x,&y)); 27 CHKERRQ(MatCreateCentering(PETSC_COMM_WORLD,PETSC_DECIDE,n,&C)); 28 CHKERRQ(MatMult(C,x,y)); 29 30 /* Verify that the centered vector y has norm 0. */ 31 CHKERRQ(VecNorm(y,NORM_2,&norm)); 32 CHKERRQ(PetscPrintf(PETSC_COMM_WORLD,"Vector norm after MatMult() with centering matrix applied to vector of ones is %f.\n",(double)norm)); 33 34 /* Now repeat, but using MatMultTranspose(). */ 35 CHKERRQ(MatMultTranspose(C,x,y)); 36 CHKERRQ(VecNorm(y,NORM_2,&norm)); 37 CHKERRQ(PetscPrintf(PETSC_COMM_WORLD,"Vector norm after MatMultTranspose() with centering matrix applied to vector of ones is %f.\n",(double)norm)); 38 39 /* Clean up. */ 40 CHKERRQ(VecDestroy(&x)); 41 CHKERRQ(VecDestroy(&y)); 42 CHKERRQ(MatDestroy(&C)); 43 ierr = PetscFinalize(); 44 return ierr; 45 } 46 47 /*TEST 48 49 test: 50 suffix: 1 51 nsize: 1 52 output_file: output/ex247.out 53 54 test: 55 suffix: 2 56 nsize: 2 57 output_file: output/ex247.out 58 59 TEST*/ 60