1c4762a1bSJed Brown static char help[] = "Example of inverting a block diagonal matrix.\n" 2c4762a1bSJed Brown "\n"; 3c4762a1bSJed Brown 4c4762a1bSJed Brown #include <petscmat.h> 5c4762a1bSJed Brown 6*9371c9d4SSatish Balay int main(int argc, char **args) { 7c4762a1bSJed Brown Mat A, A_inv; 8c4762a1bSJed Brown PetscMPIInt rank, size; 9c4762a1bSJed Brown PetscInt M, m, bs, rstart, rend, j, x, y; 10c4762a1bSJed Brown PetscInt *dnnz; 11c4762a1bSJed Brown PetscScalar *v; 12c4762a1bSJed Brown Vec X, Y; 13c4762a1bSJed Brown PetscReal norm; 14c4762a1bSJed Brown 15327415f7SBarry Smith PetscFunctionBeginUser; 169566063dSJacob Faibussowitsch PetscCall(PetscInitialize(&argc, &args, (char *)0, help)); 179566063dSJacob Faibussowitsch PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size)); 189566063dSJacob Faibussowitsch PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank)); 19c4762a1bSJed Brown 20d0609cedSBarry Smith PetscOptionsBegin(PETSC_COMM_WORLD, NULL, "ex184", "Mat"); 21c4762a1bSJed Brown M = 8; 229566063dSJacob Faibussowitsch PetscCall(PetscOptionsGetInt(NULL, NULL, "-mat_size", &M, NULL)); 23c4762a1bSJed Brown bs = 3; 249566063dSJacob Faibussowitsch PetscCall(PetscOptionsGetInt(NULL, NULL, "-mat_block_size", &bs, NULL)); 25d0609cedSBarry Smith PetscOptionsEnd(); 26c4762a1bSJed Brown 279566063dSJacob Faibussowitsch PetscCall(MatCreate(PETSC_COMM_WORLD, &A)); 289566063dSJacob Faibussowitsch PetscCall(MatSetFromOptions(A)); 299566063dSJacob Faibussowitsch PetscCall(MatSetSizes(A, PETSC_DECIDE, PETSC_DECIDE, M * bs, M * bs)); 309566063dSJacob Faibussowitsch PetscCall(MatSetBlockSize(A, bs)); 319566063dSJacob Faibussowitsch PetscCall(MatSetUp(A)); 329566063dSJacob Faibussowitsch PetscCall(MatGetLocalSize(A, &m, NULL)); 339566063dSJacob Faibussowitsch PetscCall(PetscMalloc1(m / bs, &dnnz)); 34*9371c9d4SSatish Balay for (j = 0; j < m / bs; j++) { dnnz[j] = 1; } 359566063dSJacob Faibussowitsch PetscCall(MatXAIJSetPreallocation(A, bs, dnnz, NULL, NULL, NULL)); 369566063dSJacob Faibussowitsch PetscCall(PetscFree(dnnz)); 37c4762a1bSJed Brown 389566063dSJacob Faibussowitsch PetscCall(PetscMalloc1(bs * bs, &v)); 399566063dSJacob Faibussowitsch PetscCall(MatGetOwnershipRange(A, &rstart, &rend)); 40c4762a1bSJed Brown for (j = rstart / bs; j < rend / bs; j++) { 41c4762a1bSJed Brown for (x = 0; x < bs; x++) { 42c4762a1bSJed Brown for (y = 0; y < bs; y++) { 43c4762a1bSJed Brown if (x == y) { 44c4762a1bSJed Brown v[y + bs * x] = 2 * bs; 45c4762a1bSJed Brown } else { 46c4762a1bSJed Brown v[y + bs * x] = -1 * (x < y) - 2 * (x > y); 47c4762a1bSJed Brown } 48c4762a1bSJed Brown } 49c4762a1bSJed Brown } 509566063dSJacob Faibussowitsch PetscCall(MatSetValuesBlocked(A, 1, &j, 1, &j, v, INSERT_VALUES)); 51c4762a1bSJed Brown } 529566063dSJacob Faibussowitsch PetscCall(PetscFree(v)); 539566063dSJacob Faibussowitsch PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY)); 549566063dSJacob Faibussowitsch PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY)); 55c4762a1bSJed Brown 56c4762a1bSJed Brown /* check that A = inv(inv(A)) */ 579566063dSJacob Faibussowitsch PetscCall(MatCreate(PETSC_COMM_WORLD, &A_inv)); 589566063dSJacob Faibussowitsch PetscCall(MatSetFromOptions(A_inv)); 599566063dSJacob Faibussowitsch PetscCall(MatInvertBlockDiagonalMat(A, A_inv)); 60c4762a1bSJed Brown 61c4762a1bSJed Brown /* Test A_inv * A on a random vector */ 629566063dSJacob Faibussowitsch PetscCall(MatCreateVecs(A, &X, &Y)); 639566063dSJacob Faibussowitsch PetscCall(VecSetRandom(X, NULL)); 649566063dSJacob Faibussowitsch PetscCall(MatMult(A, X, Y)); 659566063dSJacob Faibussowitsch PetscCall(VecScale(X, -1)); 669566063dSJacob Faibussowitsch PetscCall(MatMultAdd(A_inv, Y, X, X)); 679566063dSJacob Faibussowitsch PetscCall(VecNorm(X, NORM_MAX, &norm)); 68c4762a1bSJed Brown if (norm > PETSC_SMALL) { 699566063dSJacob Faibussowitsch PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Norm of error exceeds tolerance.\nInverse of block diagonal A\n")); 709566063dSJacob Faibussowitsch PetscCall(MatView(A_inv, PETSC_VIEWER_STDOUT_WORLD)); 71c4762a1bSJed Brown } 72c4762a1bSJed Brown 739566063dSJacob Faibussowitsch PetscCall(MatDestroy(&A)); 749566063dSJacob Faibussowitsch PetscCall(MatDestroy(&A_inv)); 759566063dSJacob Faibussowitsch PetscCall(VecDestroy(&X)); 769566063dSJacob Faibussowitsch PetscCall(VecDestroy(&Y)); 77c4762a1bSJed Brown 789566063dSJacob Faibussowitsch PetscCall(PetscFinalize()); 79b122ec5aSJacob Faibussowitsch return 0; 80c4762a1bSJed Brown } 81c4762a1bSJed Brown 82c4762a1bSJed Brown /*TEST 83c4762a1bSJed Brown test: 84c4762a1bSJed Brown suffix: seqaij 85c4762a1bSJed Brown args: -mat_type seqaij -mat_size 12 -mat_block_size 3 86c4762a1bSJed Brown nsize: 1 87c4762a1bSJed Brown test: 88c4762a1bSJed Brown suffix: seqbaij 89c4762a1bSJed Brown args: -mat_type seqbaij -mat_size 12 -mat_block_size 3 90c4762a1bSJed Brown nsize: 1 91c4762a1bSJed Brown test: 92c4762a1bSJed Brown suffix: mpiaij 93c4762a1bSJed Brown args: -mat_type mpiaij -mat_size 12 -mat_block_size 3 94c4762a1bSJed Brown nsize: 2 95c4762a1bSJed Brown test: 96c4762a1bSJed Brown suffix: mpibaij 97c4762a1bSJed Brown args: -mat_type mpibaij -mat_size 12 -mat_block_size 3 98c4762a1bSJed Brown nsize: 2 99c4762a1bSJed Brown TEST*/ 100