linsys_BDDC.cc

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/*!
 *
 * Copyright (C) 2015 Technical University of Liberec.  All rights reserved.
 * 
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License version 3 as published by the
 * Free Software Foundation. (http://www.gnu.org/licenses/gpl-3.0.en.html)
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
 *
 * 
 * @file    linsys_BDDC.cc
 * @brief   Solver based on Multilevel BDDC - using corresponding class of OpenFTL package
 * @author  Jakub Sistek
 */

#include <mpi.h>
#include "config.h"


// need BDDCML wrapper
#ifdef FLOW123D_HAVE_BDDCML
  #include <map>
  #include "la/bddcml_wrapper.hh"
#endif // FLOW123D_HAVE_BDDCML

#include "la/linsys.hh"
#include "la/linsys_BDDC.hh"
#include "system/sys_profiler.hh"



namespace it = Input::Type;


const it::Record & LinSys_BDDC::get_input_type() {
    return it::Record("Bddc", "BDDCML (Balancing Domain Decomposition by Constraints - Multi-Level) solver settings.")
        .derive_from(LinSys::get_input_type())
        .declare_key("r_tol", it::Double(0.0, 1.0), it::Default::read_time("Default value is set by the nonlinear solver or the equation. "
                        "If not, we use the value 1.0e-7."),
                    "Residual tolerance relative to the initial error.")
        .declare_key("max_it", it::Integer(0), it::Default::read_time("Default value is set by the nonlinear solver or the equation. "
                        "If not, we use the value 1000."),
                    "Maximum number of outer iterations of the linear solver.")

        .declare_key("max_nondecr_it", it::Integer(0), it::Default("30"),
                     "Maximum number of iterations of the linear solver with non-decreasing residual.")
        .declare_key("number_of_levels", it::Integer(0), it::Default("2"),
                     "Number of levels in the multilevel method (=2 for the standard BDDC).")
        .declare_key("use_adaptive_bddc", it::Bool(), it::Default("false"),
                     "Use adaptive selection of constraints in BDDCML.")
        .declare_key("bddcml_verbosity_level", it::Integer(0,2), it::Default("0"),
                     "Level of verbosity of the BDDCML library:\n\n - 0 - no output,\n - 1 - mild output,\n - 2 - detailed output.")
        .close();
}


const int LinSys_BDDC::registrar = LinSys_BDDC::get_input_type().size();



LinSys_BDDC::LinSys_BDDC(  const Distribution * rows_ds,
                           const bool swap_sign )
        : LinSys( rows_ds ),
          swap_sign_(swap_sign)
{
#ifdef FLOW123D_HAVE_BDDCML
    // from the point of view of assembly, BDDC linsys is in the ADD state
    status_ = LinSys::ADD;
#else
    throw ExcInputMessage << EI_Message("Unsupported solver BDDC. Compiled without support for the BDDCML solver.")''
#endif // FLOW123D_HAVE_BDDCML
}


void LinSys_BDDC::set_tolerances(double  r_tol, FMT_UNUSED double a_tol, unsigned int max_it)
{
    if (! in_rec_.is_empty()) {
        // input record is set
        r_tol_ = in_rec_.val<double>("r_tol", r_tol);
        // BDDC does not use a_tol_
        a_tol_ = 0.01 * r_tol_;
        max_it_ = in_rec_.val<unsigned int>("max_it", max_it);\
    }
}


void LinSys_BDDC::load_mesh( BDDCMatrixType matrix_type,
                             const int nDim, const int numNodes, FMT_UNUSED const int numDofs,
                             const std::vector<int> & inet, 
                             const std::vector<int> & nnet, 
                             const std::vector<int> & nndf, 
                             const std::vector<int> & isegn, 
                             const std::vector<int> & isngn, 
                             const std::vector<int> & isvgvn,
                             const std::vector<double> & xyz,
                             const std::vector<double> & element_permeability,
                             const int meshDim ) 
{
#ifdef FLOW123D_HAVE_BDDCML

    uint num_of_local_subdomains = 1;
    bddcml_ = new Bddcml_( size_,
                           nndf.size(),
                           matrix_type,
                           rows_ds_->get_comm(),
                           num_of_local_subdomains);

    // prepare space for local solution
    locSolution_.resize( nndf.size() );
    chkerr( VecCreateSeqWithArray( PETSC_COMM_SELF, 1, nndf.size(), &(locSolution_[0]), &locSolVec_ ));

    // simply pass the data to BDDCML solver
    isngn_.resize(isngn.size());
    std::copy( isngn.begin(), isngn.end(), isngn_.begin() );
    OLD_ASSERT( numDofs == static_cast<int>(size_), "Global problem size mismatch!" );

    bddcml_ -> loadRawMesh( nDim, numNodes, inet, nnet, nndf, isegn, isngn, isvgvn, xyz, element_permeability, meshDim );

    // create a map for BDDCML to PETSc vector
    PetscErrorCode ierr;

    // local index set
    PetscInt numDofsSubInt = static_cast<int>( isngn_.size( ) );
    std::vector<PetscInt> idx( isngn_ );

    ISLocalToGlobalMapping subdomainMapping;
    ierr = ISLocalToGlobalMappingCreate( comm_, 1, numDofsSubInt, &(idx[0]), PETSC_COPY_VALUES, &subdomainMapping ); CHKERRV( ierr );
    
    IS subdomainIndexSet;
    IS from;
    ierr = ISCreateStride( PETSC_COMM_SELF, numDofsSubInt, 0, 1, &subdomainIndexSet ); 
    ierr = ISLocalToGlobalMappingApplyIS( subdomainMapping, subdomainIndexSet, &from ); 


    // create scatter from parallel PETSc vector to local indices of subdomain
    ierr = VecScatterCreate( solution_, from, locSolVec_, subdomainIndexSet, &VSpetscToSubScatter_ ); CHKERRV( ierr );
    chkerr(ISDestroy( &subdomainIndexSet ));
    chkerr(ISDestroy( &from ));

    //double * locSolVecArray;
    //ierr = VecGetArray( locSolVec_, &locSolVecArray ); CHKERRV( ierr );
    //std::copy( locSolution_.begin(), locSolution_.end(), locSolVecArray );
    //ierr = VecRestoreArray( locSolVec_, &locSolVecArray ); CHKERRV( ierr );

    // scatter local solutions back to global one
    VecScatterBegin( VSpetscToSubScatter_, locSolVec_, solution_, INSERT_VALUES, SCATTER_REVERSE ); 
    VecScatterEnd(   VSpetscToSubScatter_, locSolVec_, solution_, INSERT_VALUES, SCATTER_REVERSE );
#endif // FLOW123D_HAVE_BDDCML
}

void LinSys_BDDC::mat_set_values( int nrow, int *rows, int ncol, int *cols, double *vals )
{
#ifdef FLOW123D_HAVE_BDDCML
    namespace ublas = boost::numeric::ublas;

    std::vector< unsigned >  myRows( nrow ); 
    std::vector< unsigned >  myCols( ncol ); 
    ublas::matrix< double >  mat( nrow, ncol ); 

    std::copy( &(rows[0]), &(rows[nrow]), myRows.begin() );
    std::copy( &(cols[0]), &(cols[ncol]), myCols.begin() );

    for ( int i = 0; i < nrow; i++ ) {
        for ( int j = 0; j < ncol; j++ ) {
            mat( i, j ) = vals[i*ncol + j];
        }
    }
    if (swap_sign_) {
       mat = -mat;
    }

    bddcml_ -> insertToMatrix( mat, myRows, myCols );
#endif // FLOW123D_HAVE_BDDCML
} 

void LinSys_BDDC::rhs_set_values( int nrow, int *rows, double *vals)
{
#ifdef FLOW123D_HAVE_BDDCML
    namespace ublas = boost::numeric::ublas;

    std::vector< unsigned >  myRows( nrow ); 
    ublas::vector< double >  vec( nrow ); 

    std::copy( &(rows[0]), &(rows[nrow]), myRows.begin() );

    for ( int i = 0; i < nrow; i++ ) {
        vec( i ) = vals[i];
    }
    if (swap_sign_) {
       vec = -vec;
    }

    bddcml_ -> insertToRhs( vec, myRows );
#endif // FLOW123D_HAVE_BDDCML
}

void LinSys_BDDC::diagonal_weights_set_value( int global_index, double value )
{
#ifdef FLOW123D_HAVE_BDDCML
    bddcml_ -> insertToDiagonalWeights( global_index, value );
#endif // FLOW123D_HAVE_BDDCML
}

PetscErrorCode LinSys_BDDC::mat_zero_entries()
{
#ifdef FLOW123D_HAVE_BDDCML
    bddcml_ -> clearMatrix( );
#endif // FLOW123D_HAVE_BDDCML
    return 0;
}

PetscErrorCode LinSys_BDDC::rhs_zero_entries()
{
#ifdef FLOW123D_HAVE_BDDCML
    bddcml_ -> clearRhs( );
#endif // FLOW123D_HAVE_BDDCML
    return 0;
}

void LinSys_BDDC::finish_assembly( )
{
#ifdef FLOW123D_HAVE_BDDCML
    bddcml_ -> finishMatAssembly( );
#endif // FLOW123D_HAVE_BDDCML
}

void LinSys_BDDC::apply_constrains( double scalar )
{
#ifdef FLOW123D_HAVE_BDDCML
    bddcml_ -> applyConstraints( constraints_, 1., scalar );
#endif // FLOW123D_HAVE_BDDCML
}

LinSys::SolveInfo LinSys_BDDC::solve()    // ! params are not currently used
{
#ifdef FLOW123D_HAVE_BDDCML
    std::vector<int> *  numSubAtLevels = NULL;  //!< number of subdomains at levels
    START_TIMER("BDDC linear solver");

    {

        START_TIMER("BDDC linear iteration");
        bddcml_ -> solveSystem( r_tol_, number_of_levels_, numSubAtLevels, bddcml_verbosity_level_, max_it_, max_nondecr_it_, use_adaptive_bddc_ );


        LogOut().fmt("BDDCML converged reason: {} ( 0 means OK ) \n", bddcml_ -> giveConvergedReason() );
        LogOut().fmt("BDDCML converged in {} iterations. \n", bddcml_ -> giveNumIterations() );
        LogOut().fmt("BDDCML estimated condition number is {} \n", bddcml_ -> giveCondNumber() );
        ADD_CALLS(bddcml_ -> giveNumIterations());
    }

    // download local solution
    bddcml_ -> giveSolution( isngn_, locSolution_ ); 


    double * locSolVecArray;
    VecGetArray( locSolVec_, &locSolVecArray ); 
    std::copy( locSolution_.begin(), locSolution_.end(), locSolVecArray );
    VecRestoreArray( locSolVec_, &locSolVecArray ); 

    // scatter local solutions back to global one
    VecScatterBegin( VSpetscToSubScatter_, locSolVec_, solution_, INSERT_VALUES, SCATTER_REVERSE ); 
    VecScatterEnd(   VSpetscToSubScatter_, locSolVec_, solution_, INSERT_VALUES, SCATTER_REVERSE );

    // upper bound on the residual error
    residual_norm_ = r_tol_ * bddcml_->normRhs( ) ;

    return LinSys::SolveInfo(bddcml_ -> giveConvergedReason(), bddcml_ -> giveNumIterations());
#else
    return LinSys::SolveInfo(0,0);
#endif // FLOW123D_HAVE_BDDCML

}

void LinSys_BDDC::set_from_input(const Input::Record in_rec)
{
    LinSys::set_from_input(in_rec);

    // BDDCML specific parameters
    max_nondecr_it_         = in_rec.val<int>("max_nondecr_it");   
    number_of_levels_       = in_rec.val<int>("number_of_levels");   
    use_adaptive_bddc_      = in_rec.val<bool>("use_adaptive_bddc");
    bddcml_verbosity_level_ = in_rec.val<int>("bddcml_verbosity_level");
}

LinSys_BDDC::~LinSys_BDDC()
{ 
#ifdef FLOW123D_HAVE_BDDCML
    isngn_.clear();
    locSolution_.clear(); 

    chkerr(VecDestroy( &locSolVec_ ));

    chkerr(VecScatterDestroy( &VSpetscToSubScatter_ ));

    delete bddcml_;
#endif // FLOW123D_HAVE_BDDCML
}

// construct global solution
//void LinSys_BDDC::gatherSolution_( )
//{
//#ifdef FLOW123D_HAVE_BDDCML
//    int ierr;
//
//    // merge solution on root
//    int rank;
//    MPI_Comm_rank( comm_, &rank );
//    int nProc;
//    MPI_Comm_size( comm_, &nProc );
//
//    globalSolution_.resize( size_ );
//    std::vector<double> locSolutionNeib;
//    if ( rank == 0 ) {
//        // merge my own data
//        for ( unsigned int i = 0; i < isngn_.size(); i++ ) {
//            int ind = isngn_[i];
//            globalSolution_[ind] = locSolution_[i];
//        }
//        for ( int iProc = 1; iProc < nProc; iProc++ ) {
//            // receive length
//            int length;
//            MPI_Status status;
//            ierr = MPI_Recv( &length, 1, MPI_INT, iProc, iProc, comm_, &status ); 
//
//            // receive indices
//            std::vector<int> inds( length );
//            ierr = MPI_Recv( &(inds[0]), length, MPI_INT, iProc, iProc, comm_, &status ); 
//
//            // receive local solution
//            locSolutionNeib.resize( length );
//            ierr = MPI_Recv( &(locSolutionNeib[0]), length, MPI_DOUBLE, iProc, iProc, comm_, &status ); 
//
//            // merge data
//            for ( int i = 0; i < length; i++ ) {
//                int ind = inds[i];
//                globalSolution_[ind] = locSolutionNeib[i];
//            }
//        }
//    }
//    else {
//        // send my solution to root
//        int length = isngn_.size();
//        ierr = MPI_Send( &length,                1, MPI_INT,    0, rank, comm_ ); 
//        ierr = MPI_Send( &(isngn_[0]),      length, MPI_INT,    0, rank, comm_ ); 
//        ierr = MPI_Send( &(locSolution_[0]), length, MPI_DOUBLE, 0, rank, comm_ ); 
//    }
//    // broadcast global solution from root
//    ierr = MPI_Bcast( &(globalSolution_[0]), globalSolution_.size(), MPI_DOUBLE, 0, comm_ );
//#endif // FLOW123D_HAVE_BDDCML
//}

double LinSys_BDDC::get_solution_precision()
{
    double bnorm=0.0;
    VecNorm(locSolVec_, NORM_2, &bnorm);

    return max(a_tol_, r_tol_*bnorm);
}


void LinSys_BDDC::print_matrix(std::ostream& out)
{
    int rank;
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
    
    if(rank == 0){
        out << "zzz = [\n";
    
        bddcml_->writeMatrix(out);
        out << "];\n" 
            << "zzz(:,1:2) = zzz(:,1:2) + ones(size(zzz),2);\n" // fix matlab indices (+1)
            << "matrix_bddc = spconvert(zzz);\n";
    }
}