bool sillyCgSolve( const Thyra::LinearOpBase<Scalar> &A, const Thyra::VectorBase<Scalar> &b, const int maxNumIters, const typename Teuchos::ScalarTraits<Scalar>::magnitudeType tolerance, const Teuchos::Ptr<Thyra::VectorBase<Scalar> > &x, std::ostream &out ) { // Create some typedefs and some other stuff to make the code cleaner typedef Teuchos::ScalarTraits<Scalar> ST; typedef typename ST::magnitudeType ScalarMag; const Scalar one = ST::one(), zero = ST::zero(); using Teuchos::as; using Teuchos::RCP; using Thyra::VectorSpaceBase; using Thyra::VectorBase; using Thyra::NOTRANS; using Thyra::V_V; using Thyra::apply; // Validate input THYRA_ASSERT_LINEAR_OP_VEC_APPLY_SPACES("sillyCgSolve()", A, Thyra::NOTRANS, *x, &b); Teuchos::EVerbosityLevel vl = Teuchos::VERB_MEDIUM; out << "\nStarting CG solver ...\n" << std::scientific << "\ndescribe A:\n"<<describe(A, vl) << "\ndescribe b:\n"<<describe(b, vl)<<"\ndescribe x:\n"<<describe(*x, vl)<<"\n"; // Initialization const RCP<const VectorSpaceBase<Scalar> > space = A.domain(); const RCP<VectorBase<Scalar> > r = createMember(space); // r = -A*x + b V_V(r.ptr(), b); apply<Scalar>(A, NOTRANS, *x, r.ptr(), -one, one); const ScalarMag r0_nrm = norm(*r); if (r0_nrm==zero) return true; const RCP<VectorBase<Scalar> > p = createMember(space), q = createMember(space); Scalar rho_old = -one; // Perform the iterations for( int iter = 0; iter <= maxNumIters; ++iter ) { // Check convergence and output iteration const ScalarMag r_nrm = norm(*r); const bool isConverged = r_nrm/r0_nrm <= tolerance; if( iter%(maxNumIters/10+1) == 0 || iter == maxNumIters || isConverged ) { out << "Iter = " << iter << ", ||b-A*x||/||b-A*x0|| = " << (r_nrm/r0_nrm) << std::endl; if( r_nrm/r0_nrm < tolerance ) return true; // Success! } // Compute iteration const Scalar rho = inner(*r, *r); // <r,r> -> rho if (iter==0) V_V(p.ptr(), *r); // r -> p (iter == 0) else Vp_V( p.ptr(), *r, rho/rho_old ); // r+(rho/rho_old)*p -> p (iter > 0) apply<Scalar>(A, NOTRANS, *p, q.ptr()); // A*p -> q const Scalar alpha = rho/inner(*p, *q); // rho/<p,q> -> alpha Vp_StV( x, +alpha, *p ); // +alpha*p + x -> x Vp_StV( r.ptr(), -alpha, *q ); // -alpha*q + r -> r rho_old = rho; // rho -> rho_old (for next iter) } return false; // Failure } // end sillyCgSolve
RCP<const Teuchos::Comm<Thyra::Ordinal> > TpetraOperatorWrapper::getThyraComm(const Thyra::LinearOpBase<ST>& inOp) const { RCP<const VectorSpaceBase<ST> > vs = inOp.domain(); RCP<const SpmdVectorSpaceBase<ST> > spmd; RCP<const VectorSpaceBase<ST> > current = vs; while(current!=Teuchos::null) { // try to cast to a product vector space first RCP<const ProductVectorSpaceBase<ST> > prod = rcp_dynamic_cast<const ProductVectorSpaceBase<ST> >(current); // figure out what type it is if(prod==Teuchos::null) { // hopfully this is a SPMD vector space spmd = rcp_dynamic_cast<const SpmdVectorSpaceBase<ST> >(current); break; } else // get first convenient vector space current = prod->getBlock(0); } TEUCHOS_TEST_FOR_EXCEPTION(spmd==Teuchos::null, std::runtime_error, "TpetraOperatorWrapper requires std::vector space " "blocks to be SPMD std::vector spaces"); return spmd->getComm(); /* const Thyra::ConstLinearOperator<double> thyraOp = rcpFromRef(inOp); RCP<Epetra_Comm> rtn; // VectorSpace<double> vs = thyraOp.domain().getBlock(0); RCP<const VectorSpaceBase<double> > vs = thyraOp.domain().getBlock(0).constPtr(); // search for an SpmdVectorSpaceBase object RCP<const SpmdVectorSpaceBase<double> > spmd; RCP<const VectorSpaceBase<double> > current = vs; while(current!=Teuchos::null) { // try to cast to a product vector space first RCP<const ProductVectorSpaceBase<double> > prod = rcp_dynamic_cast<const ProductVectorSpaceBase<double> >(current); // figure out what type it is if(prod==Teuchos::null) { // hopfully this is a SPMD vector space spmd = rcp_dynamic_cast<const SpmdVectorSpaceBase<double> >(current); break; } else { // get first convenient vector space current = prod->getBlock(0); } } TEUCHOS_TEST_FOR_EXCEPTION(spmd==Teuchos::null, std::runtime_error, "TpetraOperatorWrapper requires std::vector space " "blocks to be SPMD std::vector spaces"); const SerialComm<Thyra::Ordinal>* serialComm = dynamic_cast<const SerialComm<Thyra::Ordinal>*>(spmd->getComm().get()); #ifdef HAVE_MPI const MpiComm<Thyra::Ordinal>* mpiComm = dynamic_cast<const MpiComm<Thyra::Ordinal>*>(spmd->getComm().get()); TEUCHOS_TEST_FOR_EXCEPTION(mpiComm==0 && serialComm==0, std::runtime_error, "SPMD std::vector space has a communicator that is " "neither a serial comm nor an MPI comm"); if (mpiComm != 0) { rtn = rcp(new Epetra_MpiComm(MPI_COMM_WORLD)); } else { rtn = rcp(new Epetra_SerialComm()); } #else TEUCHOS_TEST_FOR_EXCEPTION(serialComm==0, std::runtime_error, "SPMD std::vector space has a communicator that is " "neither a serial comm nor an MPI comm"); rtn = rcp(new Epetra_SerialComm()); #endif TEUCHOS_TEST_FOR_EXCEPTION(rtn.get()==0, std::runtime_error, "null communicator created"); return rtn; */ }