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 6c4762a1bSJed Brown int main(int argc, char **args) 7c4762a1bSJed Brown { 8c4762a1bSJed Brown Mat A,A_inv; 9c4762a1bSJed Brown PetscMPIInt rank,size; 10c4762a1bSJed Brown PetscInt M,m,bs,rstart,rend,j,x,y; 11c4762a1bSJed Brown PetscInt* dnnz; 12c4762a1bSJed Brown PetscScalar *v; 13c4762a1bSJed Brown Vec X, Y; 14c4762a1bSJed Brown PetscReal norm; 15c4762a1bSJed Brown 16*327415f7SBarry Smith PetscFunctionBeginUser; 179566063dSJacob Faibussowitsch PetscCall(PetscInitialize(&argc,&args,(char*)0,help)); 189566063dSJacob Faibussowitsch PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD,&size)); 199566063dSJacob Faibussowitsch PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD,&rank)); 20c4762a1bSJed Brown 21d0609cedSBarry Smith PetscOptionsBegin(PETSC_COMM_WORLD,NULL,"ex184","Mat"); 22c4762a1bSJed Brown M=8; 239566063dSJacob Faibussowitsch PetscCall(PetscOptionsGetInt(NULL,NULL,"-mat_size",&M,NULL)); 24c4762a1bSJed Brown bs=3; 259566063dSJacob Faibussowitsch PetscCall(PetscOptionsGetInt(NULL,NULL,"-mat_block_size",&bs,NULL)); 26d0609cedSBarry Smith PetscOptionsEnd(); 27c4762a1bSJed Brown 289566063dSJacob Faibussowitsch PetscCall(MatCreate(PETSC_COMM_WORLD, &A)); 299566063dSJacob Faibussowitsch PetscCall(MatSetFromOptions(A)); 309566063dSJacob Faibussowitsch PetscCall(MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,M*bs,M*bs)); 319566063dSJacob Faibussowitsch PetscCall(MatSetBlockSize(A,bs)); 329566063dSJacob Faibussowitsch PetscCall(MatSetUp(A)); 339566063dSJacob Faibussowitsch PetscCall(MatGetLocalSize(A,&m,NULL)); 349566063dSJacob Faibussowitsch PetscCall(PetscMalloc1(m/bs,&dnnz)); 35c4762a1bSJed Brown for (j = 0; j < m/bs; j++) { 36c4762a1bSJed Brown dnnz[j] = 1; 37c4762a1bSJed Brown } 389566063dSJacob Faibussowitsch PetscCall(MatXAIJSetPreallocation(A,bs,dnnz,NULL,NULL,NULL)); 399566063dSJacob Faibussowitsch PetscCall(PetscFree(dnnz)); 40c4762a1bSJed Brown 419566063dSJacob Faibussowitsch PetscCall(PetscMalloc1(bs*bs,&v)); 429566063dSJacob Faibussowitsch PetscCall(MatGetOwnershipRange(A,&rstart,&rend)); 43c4762a1bSJed Brown for (j = rstart/bs; j < rend/bs; j++) { 44c4762a1bSJed Brown for (x = 0; x < bs; x++) { 45c4762a1bSJed Brown for (y = 0; y < bs; y++) { 46c4762a1bSJed Brown if (x == y) { 47c4762a1bSJed Brown v[y+bs*x] = 2*bs; 48c4762a1bSJed Brown } else { 49c4762a1bSJed Brown v[y+bs*x] = -1 * (x < y) - 2 * (x > y); 50c4762a1bSJed Brown } 51c4762a1bSJed Brown } 52c4762a1bSJed Brown } 539566063dSJacob Faibussowitsch PetscCall(MatSetValuesBlocked(A,1,&j,1,&j,v,INSERT_VALUES)); 54c4762a1bSJed Brown } 559566063dSJacob Faibussowitsch PetscCall(PetscFree(v)); 569566063dSJacob Faibussowitsch PetscCall(MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY)); 579566063dSJacob Faibussowitsch PetscCall(MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY)); 58c4762a1bSJed Brown 59c4762a1bSJed Brown /* check that A = inv(inv(A)) */ 609566063dSJacob Faibussowitsch PetscCall(MatCreate(PETSC_COMM_WORLD,&A_inv)); 619566063dSJacob Faibussowitsch PetscCall(MatSetFromOptions(A_inv)); 629566063dSJacob Faibussowitsch PetscCall(MatInvertBlockDiagonalMat(A,A_inv)); 63c4762a1bSJed Brown 64c4762a1bSJed Brown /* Test A_inv * A on a random vector */ 659566063dSJacob Faibussowitsch PetscCall(MatCreateVecs(A, &X, &Y)); 669566063dSJacob Faibussowitsch PetscCall(VecSetRandom(X, NULL)); 679566063dSJacob Faibussowitsch PetscCall(MatMult(A, X, Y)); 689566063dSJacob Faibussowitsch PetscCall(VecScale(X, -1)); 699566063dSJacob Faibussowitsch PetscCall(MatMultAdd(A_inv, Y, X, X)); 709566063dSJacob Faibussowitsch PetscCall(VecNorm(X, NORM_MAX, &norm)); 71c4762a1bSJed Brown if (norm > PETSC_SMALL) { 729566063dSJacob Faibussowitsch PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Norm of error exceeds tolerance.\nInverse of block diagonal A\n")); 739566063dSJacob Faibussowitsch PetscCall(MatView(A_inv,PETSC_VIEWER_STDOUT_WORLD)); 74c4762a1bSJed Brown } 75c4762a1bSJed Brown 769566063dSJacob Faibussowitsch PetscCall(MatDestroy(&A)); 779566063dSJacob Faibussowitsch PetscCall(MatDestroy(&A_inv)); 789566063dSJacob Faibussowitsch PetscCall(VecDestroy(&X)); 799566063dSJacob Faibussowitsch PetscCall(VecDestroy(&Y)); 80c4762a1bSJed Brown 819566063dSJacob Faibussowitsch PetscCall(PetscFinalize()); 82b122ec5aSJacob Faibussowitsch return 0; 83c4762a1bSJed Brown } 84c4762a1bSJed Brown 85c4762a1bSJed Brown /*TEST 86c4762a1bSJed Brown test: 87c4762a1bSJed Brown suffix: seqaij 88c4762a1bSJed Brown args: -mat_type seqaij -mat_size 12 -mat_block_size 3 89c4762a1bSJed Brown nsize: 1 90c4762a1bSJed Brown test: 91c4762a1bSJed Brown suffix: seqbaij 92c4762a1bSJed Brown args: -mat_type seqbaij -mat_size 12 -mat_block_size 3 93c4762a1bSJed Brown nsize: 1 94c4762a1bSJed Brown test: 95c4762a1bSJed Brown suffix: mpiaij 96c4762a1bSJed Brown args: -mat_type mpiaij -mat_size 12 -mat_block_size 3 97c4762a1bSJed Brown nsize: 2 98c4762a1bSJed Brown test: 99c4762a1bSJed Brown suffix: mpibaij 100c4762a1bSJed Brown args: -mat_type mpibaij -mat_size 12 -mat_block_size 3 101c4762a1bSJed Brown nsize: 2 102c4762a1bSJed Brown TEST*/ 103