void
LocalSparseTriangularSolver<MatrixType>::
localApply (const MV& X,
MV& Y,
const Teuchos::ETransp mode,
const scalar_type& alpha,
const scalar_type& beta) const
{
using Teuchos::RCP;
typedef scalar_type ST;
typedef Teuchos::ScalarTraits<ST> STS;
if (beta == STS::zero ()) {
if (alpha == STS::zero ()) {
Y.putScalar (STS::zero ()); // Y := 0 * Y (ignore contents of Y)
}
else { // alpha != 0
A_crs_->template localSolve<ST, ST> (X, Y, mode);
if (alpha != STS::one ()) {
Y.scale (alpha);
}
}
}
else { // beta != 0
if (alpha == STS::zero ()) {
Y.scale (beta); // Y := beta * Y
}
else { // alpha != 0
MV Y_tmp (Y, Teuchos::Copy);
A_crs_->template localSolve<ST, ST> (X, Y_tmp, mode); // Y_tmp := M * X
Y.update (alpha, Y_tmp, beta); // Y := beta * Y + alpha * Y_tmp
}
}
}
//! Do the transpose or conjugate transpose solve.
void applyTranspose (const MV& X_in, MV& Y_in, const Teuchos::ETransp mode) const
{
typedef Teuchos::ScalarTraits<Scalar> ST;
using Teuchos::null;
TEUCHOS_TEST_FOR_EXCEPTION
(mode != Teuchos::TRANS && mode != Teuchos::CONJ_TRANS, std::logic_error,
"Tpetra::CrsMatrixSolveOp::applyTranspose: mode is neither TRANS nor "
"CONJ_TRANS. Should never get here! Please report this bug to the "
"Tpetra developers.");
const size_t numVectors = X_in.getNumVectors();
Teuchos::RCP<const Import<LocalOrdinal,GlobalOrdinal,Node> > importer =
matrix_->getGraph ()->getImporter ();
Teuchos::RCP<const Export<LocalOrdinal,GlobalOrdinal,Node> > exporter =
matrix_->getGraph ()->getExporter ();
Teuchos::RCP<const MV> X;
// it is okay if X and Y reference the same data, because we can
// perform a triangular solve in-situ. however, we require that
// column access to each is strided.
// set up import/export temporary multivectors
if (importer != null) {
if (importMV_ != null && importMV_->getNumVectors() != numVectors) {
importMV_ = null;
}
if (importMV_ == null) {
importMV_ = Teuchos::rcp( new MV(matrix_->getColMap(),numVectors) );
}
}
if (exporter != null) {
if (exportMV_ != null && exportMV_->getNumVectors() != numVectors) {
exportMV_ = null;
}
if (exportMV_ == null) {
exportMV_ = Teuchos::rcp( new MV(matrix_->getRowMap(),numVectors) );
}
}
// solve(TRANS): DomainMap -> RangeMap
// lclMatSolve_(TRANS): ColMap -> RowMap
// importer: DomainMap -> ColMap
// exporter: RowMap -> RangeMap
//
// solve = importer o lclMatSolve_ o exporter
// Domainmap -> ColMap -> RowMap -> RangeMap
//
// If we have a non-trivial importer, we must import elements that
// are permuted or are on other processes.
if (importer != null) {
importMV_->doImport(X_in,*importer,INSERT);
X = importMV_;
}
else if (X_in.isConstantStride() == false) {
// cannot handle non-constant stride right now
// generate a copy of X_in
X = Teuchos::rcp(new MV(X_in));
}
else {
// just temporary, so this non-owning RCP is okay
X = Teuchos::rcpFromRef (X_in);
}
// If we have a non-trivial exporter, we must export elements that
// are permuted or belong to other processes. We will compute
// solution into the to-be-exported MV; get a view.
if (exporter != null) {
matrix_->template localSolve<Scalar, Scalar> (*X, *exportMV_,
Teuchos::CONJ_TRANS);
// Make sure target is zero: necessary because we are adding
Y_in.putScalar(ST::zero());
Y_in.doExport(*importMV_, *importer, ADD);
}
// otherwise, solve into Y
else {
if (Y_in.isConstantStride() == false) {
// generate a strided copy of Y
MV Y(Y_in);
matrix_->template localSolve<Scalar, Scalar> (*X, Y, Teuchos::CONJ_TRANS);
Y_in = Y;
}
else {
matrix_->template localSolve<Scalar, Scalar> (*X, Y_in, Teuchos::CONJ_TRANS);
}
}
}
//! Do the non-transpose solve.
void applyNonTranspose (const MV& X_in, MV& Y_in) const
{
using Teuchos::NO_TRANS;
using Teuchos::null;
typedef Teuchos::ScalarTraits<Scalar> ST;
// Solve U X = Y or L X = Y
// X belongs to domain map, while Y belongs to range map
const size_t numVectors = X_in.getNumVectors();
Teuchos::RCP<const Import<LocalOrdinal,GlobalOrdinal,Node> > importer =
matrix_->getGraph ()->getImporter ();
Teuchos::RCP<const Export<LocalOrdinal,GlobalOrdinal,Node> > exporter =
matrix_->getGraph ()->getExporter ();
Teuchos::RCP<const MV> X;
// it is okay if X and Y reference the same data, because we can
// perform a triangular solve in-situ. however, we require that
// column access to each is strided.
// set up import/export temporary multivectors
if (importer != null) {
if (importMV_ != null && importMV_->getNumVectors () != numVectors) {
importMV_ = null;
}
if (importMV_ == null) {
importMV_ = Teuchos::rcp (new MV (matrix_->getColMap (), numVectors));
}
}
if (exporter != null) {
if (exportMV_ != null && exportMV_->getNumVectors () != numVectors) {
exportMV_ = null;
}
if (exportMV_ == null) {
exportMV_ = Teuchos::rcp (new MV (matrix_->getRowMap (), numVectors));
}
}
// solve(NO_TRANS): RangeMap -> DomainMap
// lclMatSolve_: RowMap -> ColMap
// importer: DomainMap -> ColMap
// exporter: RowMap -> RangeMap
//
// solve = reverse(exporter) o lclMatSolve_ o reverse(importer)
// RangeMap -> RowMap -> ColMap -> DomainMap
//
// If we have a non-trivial exporter, we must import elements that
// are permuted or are on other processors
if (exporter != null) {
exportMV_->doImport (X_in, *exporter, INSERT);
X = exportMV_;
}
else if (! X_in.isConstantStride ()) {
// cannot handle non-constant stride right now
// generate a copy of X_in
X = Teuchos::rcp (new MV (X_in));
}
else {
// just temporary, so this non-owning RCP is okay
X = Teuchos::rcpFromRef (X_in);
}
// If we have a non-trivial importer, we must export elements that
// are permuted or belong to other processes. We will compute
// solution into the to-be-exported MV.
if (importer != null) {
matrix_->template localSolve<Scalar, Scalar> (*X, *importMV_, NO_TRANS);
// Make sure target is zero: necessary because we are adding.
Y_in.putScalar (ST::zero ());
Y_in.doExport (*importMV_, *importer, ADD);
}
// otherwise, solve into Y
else {
// can't solve into non-strided multivector
if (! Y_in.isConstantStride ()) {
// generate a strided copy of Y
MV Y (Y_in);
matrix_->template localSolve<Scalar, Scalar> (*X, Y, NO_TRANS);
Tpetra::deep_copy (Y_in, Y);
}
else {
matrix_->template localSolve<Scalar, Scalar> (*X, Y_in, NO_TRANS);
}
}
}
void
Chebyshev<MatrixType>::
applyImpl (const MV& X,
MV& Y,
Teuchos::ETransp mode,
scalar_type alpha,
scalar_type beta) const
{
using Teuchos::ArrayRCP;
using Teuchos::as;
using Teuchos::RCP;
using Teuchos::rcp;
using Teuchos::rcp_const_cast;
using Teuchos::rcpFromRef;
const scalar_type zero = STS::zero();
const scalar_type one = STS::one();
// Y = beta*Y + alpha*M*X.
// If alpha == 0, then we don't need to do Chebyshev at all.
if (alpha == zero) {
if (beta == zero) { // Obey Sparse BLAS rules; avoid 0*NaN.
Y.putScalar (zero);
}
else {
Y.scale (beta);
}
return;
}
// If beta != 0, then we need to keep a copy of the initial value of
// Y, so that we can add beta*it to the Chebyshev result at the end.
// Usually this method is called with beta == 0, so we don't have to
// worry about caching Y_org.
RCP<MV> Y_orig;
if (beta != zero) {
Y_orig = rcp (new MV (Y));
}
// If X and Y point to the same memory location, we need to use a
// copy of X (X_copy) as the input MV. Otherwise, just let X_copy
// point to X.
//
// This is hopefully an uncommon use case, so we don't bother to
// optimize for it by caching X_copy.
RCP<const MV> X_copy;
bool copiedInput = false;
if (X.getLocalMV().getValues() == Y.getLocalMV().getValues()) {
X_copy = rcp (new MV (X));
copiedInput = true;
}
else {
X_copy = rcpFromRef (X);
}
// If alpha != 1, fold alpha into (a copy of) X.
//
// This is an uncommon use case, so we don't bother to optimize for
// it by caching X_copy. However, we do check whether we've already
// copied X above, to avoid a second copy.
if (alpha != one) {
RCP<MV> X_copy_nonConst = rcp_const_cast<MV> (X_copy);
if (! copiedInput) {
X_copy_nonConst = rcp (new MV (X));
copiedInput = true;
}
X_copy_nonConst->scale (alpha);
X_copy = rcp_const_cast<const MV> (X_copy_nonConst);
}
impl_.apply (*X_copy, Y);
if (beta != zero) {
Y.update (beta, *Y_orig, one); // Y = beta * Y_orig + 1 * Y
}
}
