/*@
MatSchurComplementComputeExplicitOperator - Compute the Schur complement matrix explicitly
Collective on Mat
Input Parameter:
. M - the matrix obtained with MatCreateSchurComplement()
Output Parameter:
. S - the Schur complement matrix
Note: This can be expensive, so it is mainly for testing
Level: advanced
.seealso: MatCreateSchurComplement(), MatSchurComplementUpdate()
@*/
PetscErrorCode MatSchurComplementComputeExplicitOperator(Mat M, Mat *S)
{
Mat B, C, D;
KSP ksp;
PC pc;
PetscBool isLU, isILU;
PetscReal fill = 2.0;
PetscErrorCode ierr;
PetscFunctionBegin;
ierr = MatSchurComplementGetSubMatrices(M, NULL, NULL, &B, &C, &D);CHKERRQ(ierr);
ierr = MatSchurComplementGetKSP(M, &ksp);CHKERRQ(ierr);
ierr = KSPGetPC(ksp, &pc);CHKERRQ(ierr);
ierr = PetscObjectTypeCompare((PetscObject) pc, PCLU, &isLU);CHKERRQ(ierr);
ierr = PetscObjectTypeCompare((PetscObject) pc, PCILU, &isILU);CHKERRQ(ierr);
if (isLU || isILU) {
Mat fact, Bd, AinvB, AinvBd;
PetscReal eps = 1.0e-10;
/* This can be sped up for banded LU */
ierr = KSPSetUp(ksp);CHKERRQ(ierr);
ierr = PCFactorGetMatrix(pc, &fact);CHKERRQ(ierr);
ierr = MatConvert(B, MATDENSE, MAT_INITIAL_MATRIX, &Bd);CHKERRQ(ierr);
ierr = MatDuplicate(Bd, MAT_DO_NOT_COPY_VALUES, &AinvBd);CHKERRQ(ierr);
ierr = MatMatSolve(fact, Bd, AinvBd);CHKERRQ(ierr);
ierr = MatDestroy(&Bd);CHKERRQ(ierr);
ierr = MatChop(AinvBd, eps);CHKERRQ(ierr);
ierr = MatConvert(AinvBd, MATAIJ, MAT_INITIAL_MATRIX, &AinvB);CHKERRQ(ierr);
ierr = MatDestroy(&AinvBd);CHKERRQ(ierr);
ierr = MatMatMult(C, AinvB, MAT_INITIAL_MATRIX, fill, S);CHKERRQ(ierr);
ierr = MatDestroy(&AinvB);CHKERRQ(ierr);
} else {
Mat Ainvd, Ainv;
ierr = PCComputeExplicitOperator(pc, &Ainvd);CHKERRQ(ierr);
ierr = MatConvert(Ainvd, MATAIJ, MAT_INITIAL_MATRIX, &Ainv);CHKERRQ(ierr);
ierr = MatDestroy(&Ainvd);CHKERRQ(ierr);
#if 0
/* Symmetric version */
ierr = MatPtAP(Ainv, B, MAT_INITIAL_MATRIX, fill, S);CHKERRQ(ierr);
#else
/* Nonsymmetric version */
ierr = MatMatMatMult(C, Ainv, B, MAT_INITIAL_MATRIX, fill, S);CHKERRQ(ierr);
#endif
ierr = MatDestroy(&Ainv);CHKERRQ(ierr);
}
ierr = PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD, PETSC_VIEWER_ASCII_INFO);CHKERRQ(ierr);
ierr = MatView(*S, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
ierr = PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
if (D) {
MatInfo info;
ierr = MatGetInfo(D, MAT_GLOBAL_SUM, &info);CHKERRQ(ierr);
if (info.nz_used) SETERRQ(PetscObjectComm((PetscObject) M), PETSC_ERR_SUP, "Not yet implemented");
}
PetscFunctionReturn(0);
}
/*@
MatSchurComplementComputeExplicitOperator - Compute the Schur complement matrix explicitly
Collective on Mat
Input Parameter:
. M - the matrix obtained with MatCreateSchurComplement()
Output Parameter:
. S - the Schur complement matrix
Note: This can be expensive, so it is mainly for testing
Level: advanced
.seealso: MatCreateSchurComplement(), MatSchurComplementUpdate()
@*/
PetscErrorCode MatSchurComplementComputeExplicitOperator(Mat M, Mat *S)
{
Mat B, C, D;
KSP ksp;
PC pc;
PetscBool isLU, isILU;
PetscReal fill = 2.0;
PetscErrorCode ierr;
PetscFunctionBegin;
ierr = MatSchurComplementGetSubMatrices(M, NULL, NULL, &B, &C, &D);CHKERRQ(ierr);
ierr = MatSchurComplementGetKSP(M, &ksp);CHKERRQ(ierr);
ierr = KSPGetPC(ksp, &pc);CHKERRQ(ierr);
ierr = PetscObjectTypeCompare((PetscObject) pc, PCLU, &isLU);CHKERRQ(ierr);
ierr = PetscObjectTypeCompare((PetscObject) pc, PCILU, &isILU);CHKERRQ(ierr);
if (isLU || isILU) {
Mat fact, Bd, AinvB, AinvBd;
PetscReal eps = 1.0e-10;
/* This can be sped up for banded LU */
ierr = KSPSetUp(ksp);CHKERRQ(ierr);
ierr = PCFactorGetMatrix(pc, &fact);CHKERRQ(ierr);
ierr = MatConvert(B, MATDENSE, MAT_INITIAL_MATRIX, &Bd);CHKERRQ(ierr);
ierr = MatDuplicate(Bd, MAT_DO_NOT_COPY_VALUES, &AinvBd);CHKERRQ(ierr);
ierr = MatMatSolve(fact, Bd, AinvBd);CHKERRQ(ierr);
ierr = MatDestroy(&Bd);CHKERRQ(ierr);
ierr = MatChop(AinvBd, eps);CHKERRQ(ierr);
ierr = MatConvert(AinvBd, MATAIJ, MAT_INITIAL_MATRIX, &AinvB);CHKERRQ(ierr);
ierr = MatDestroy(&AinvBd);CHKERRQ(ierr);
ierr = MatMatMult(C, AinvB, MAT_INITIAL_MATRIX, fill, S);CHKERRQ(ierr);
ierr = MatDestroy(&AinvB);CHKERRQ(ierr);
} else {
Mat Ainvd, Ainv;
ierr = PCComputeExplicitOperator(pc, &Ainvd);CHKERRQ(ierr);
ierr = MatConvert(Ainvd, MATAIJ, MAT_INITIAL_MATRIX, &Ainv);CHKERRQ(ierr);
ierr = MatDestroy(&Ainvd);CHKERRQ(ierr);
#if 0
/* Symmetric version */
ierr = MatPtAP(Ainv, B, MAT_INITIAL_MATRIX, fill, S);CHKERRQ(ierr);
#else
/* Nonsymmetric version */
ierr = MatMatMatMult(C, Ainv, B, MAT_INITIAL_MATRIX, fill, S);CHKERRQ(ierr);
#endif
ierr = MatDestroy(&Ainv);CHKERRQ(ierr);
}
if (D) {
ierr = MatAXPY(*S, -1.0, D, DIFFERENT_NONZERO_PATTERN);CHKERRQ(ierr);
}
ierr = MatScale(*S,-1.0);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
int main(int argc, char *argv[])
{
// Initialize libMesh
libMesh::LibMeshInit init(argc, argv);
libMesh::Parallel::Communicator& WorldComm = init.comm();
libMesh::PetscMatrix<libMesh::Number> matrix_A(WorldComm);
matrix_A.init(4,4,4,4);
matrix_A.set(0,0,1.);
// matrix_A.set(0,1,2.);
// matrix_A.set(0,2,3.);
// matrix_A.set(0,3,4.);
// matrix_A.set(1,0,2.);
matrix_A.set(1,1,5.);
// matrix_A.set(1,2,3.);
// matrix_A.set(1,3,7.);
// matrix_A.set(2,0,3.);
// matrix_A.set(2,1,3.);
matrix_A.set(2,2,9.);
// matrix_A.set(2,3,6.);
// matrix_A.set(3,0,4.);
// matrix_A.set(3,1,7.);
// matrix_A.set(3,2,6.);
matrix_A.set(3,3,1.);
matrix_A.close();
Mat dummy_inv_A;
MatCreate(PETSC_COMM_WORLD,&dummy_inv_A);
MatSetType(dummy_inv_A,MATMPIAIJ);
MatSetSizes(dummy_inv_A,PETSC_DECIDE,PETSC_DECIDE,4,4);
MatMPIAIJSetPreallocation(dummy_inv_A,2,NULL,0,NULL);
MatSetUp(dummy_inv_A);
// Dummy matrices
// Mat dummy_A, dummy_inv_A;
//
//
libMesh::PetscVector<libMesh::Number> vector_unity(WorldComm,4,4);
libMesh::PetscVector<libMesh::Number> vector_dummy_answer(WorldComm,4,4);
VecSet(vector_unity.vec(),1);
vector_unity.close();
VecSet(vector_dummy_answer.vec(),0);
vector_dummy_answer.close();
// Solver
// libMesh::PetscLinearSolver<libMesh::Number> KSP_dummy_solver(WorldComm);
// KSP_dummy_solver.init(&matrix_A);
// KSPSetOperators(KSP_dummy_solver.ksp(),matrix_A.mat(),NULL);
KSP ksp;
PC pc;
KSPCreate(PETSC_COMM_WORLD,&ksp);
KSPSetOperators(ksp, matrix_A.mat(), matrix_A.mat());
KSPGetPC(ksp,&pc);
PCSetFromOptions(pc);
PCType dummy_type;
PCGetType(pc,&dummy_type);
std::cout << std::endl << dummy_type << std::endl << std::endl;
// PCSetType(pc,PCSPAI);
// PCHYPRESetType(pc,"parasails");
KSPSetUp(ksp);
KSPSolve(ksp,vector_unity.vec(),vector_dummy_answer.vec());
PCComputeExplicitOperator(pc,&dummy_inv_A);
// KSPGetOperators(KSP_dummy_solver.ksp(),&dummy_A,&dummy_inv_A);
libMesh::PetscMatrix<libMesh::Number> matrix_invA(dummy_inv_A,WorldComm);
matrix_invA.close();
//
// // KSP_dummy_solver.solve(matrix_A,vector_dummy_answer,vector_unity,1E-5,10000);
//
// vector_dummy_answer.print_matlab();
//
// libMesh::PetscMatrix<libMesh::Number> product_mat(WorldComm);
matrix_A.print_matlab();
matrix_invA.print_matlab();
vector_dummy_answer.print_matlab();
return 0;
}
PETSC_EXTERN void PETSC_STDCALL pccomputeexplicitoperator_(PC pc,Mat *mat, int *__ierr ){
*__ierr = PCComputeExplicitOperator(
(PC)PetscToPointer((pc) ),mat);
}