Esempio n. 1
0
    LinearSolverISTL::LinearSolverResults
    LinearSolverISTL::solve(int size, int nonzeros,
                            const int* ia, const int* ja, const double* sa,
                            const double* rhs, double* solution)
    {
        // Build ISTL structures from input.
        // System matrix
        Mat A(size, size, nonzeros, Mat::row_wise);
        for (Mat::CreateIterator row = A.createbegin(); row != A.createend(); ++row) {
            int ri = row.index();
            for (int i = ia[ri]; i < ia[ri + 1]; ++i) {
                row.insert(ja[i]);
            }
        }
        for (int ri = 0; ri < size; ++ri) {
            for (int i = ia[ri]; i < ia[ri + 1]; ++i) {
                A[ri][ja[i]] = sa[i];
            }
        }
        // System RHS
        Vector b(size);
        std::copy(rhs, rhs + size, b.begin());
        // System solution
        Vector x(size);
        x = 0.0;

        if (linsolver_save_system_)
        {
            // Save system to files.
            writeMatrixToMatlab(A, linsolver_save_filename_ + "-mat");
            std::string rhsfile(linsolver_save_filename_ + "-rhs");
            std::ofstream rhsf(rhsfile.c_str());
            rhsf.precision(15);
            rhsf.setf(std::ios::scientific | std::ios::showpos);
            std::copy(b.begin(), b.end(),
                      std::ostream_iterator<VectorBlockType>(rhsf, "\n"));
        }
        
        int maxit = linsolver_max_iterations_;
        if (maxit == 0) {
            maxit = A.N();
        }

        LinearSolverResults res;
        switch (linsolver_type_) {
        case CG_ILU0:
            res = solveCG_ILU0(A, x, b, linsolver_residual_tolerance_, maxit, linsolver_verbosity_);
            break;
        case CG_AMG:
            res = solveCG_AMG(A, x, b, linsolver_residual_tolerance_, maxit, linsolver_verbosity_);
            break;
        case BiCGStab_ILU0:
            res = solveBiCGStab_ILU0(A, x, b, linsolver_residual_tolerance_, maxit, linsolver_verbosity_);
            break;
        default:
            std::cerr << "Unknown linsolver_type: " << int(linsolver_type_) << '\n';
            throw std::runtime_error("Unknown linsolver_type");
        }
        std::copy(x.begin(), x.end(), solution);
        return res;
    }
Esempio n. 2
0
    LinearSolverInterface::LinearSolverReport
    LinearSolverIstl::solve(const int size,
                            const int nonzeros,
                            const int* ia,
                            const int* ja,
                            const double* sa,
                            const double* rhs,
                            double* solution) const
    {
        // Build Istl structures from input.
        // System matrix
        Mat A(size, size, nonzeros, Mat::row_wise);
        for (Mat::CreateIterator row = A.createbegin(); row != A.createend(); ++row) {
            int ri = row.index();
            for (int i = ia[ri]; i < ia[ri + 1]; ++i) {
                row.insert(ja[i]);
            }
        }
        for (int ri = 0; ri < size; ++ri) {
            for (int i = ia[ri]; i < ia[ri + 1]; ++i) {
                A[ri][ja[i]] = sa[i];
            }
        }
        // System RHS
        Vector b(size);
        std::copy(rhs, rhs + size, b.begin());
        // System solution
        Vector x(size);
        x = 0.0;

        if (linsolver_save_system_)
        {
            // Save system to files.
            writeMatrixToMatlab(A, linsolver_save_filename_ + "-mat");
            std::string rhsfile(linsolver_save_filename_ + "-rhs");
            std::ofstream rhsf(rhsfile.c_str());
            rhsf.precision(15);
            rhsf.setf(std::ios::scientific | std::ios::showpos);
            std::copy(b.begin(), b.end(),
                      std::ostream_iterator<VectorBlockType>(rhsf, "\n"));
        }
        
        int maxit = linsolver_max_iterations_;
        if (maxit == 0) {
            maxit = 5000;
        }

        LinearSolverReport res;        
        switch (linsolver_type_) {
        case CG_ILU0:
            res = solveCG_ILU0(A, x, b, linsolver_residual_tolerance_, maxit, linsolver_verbosity_);
            break;
        case CG_AMG:
            res = solveCG_AMG(A, x, b, linsolver_residual_tolerance_, maxit, linsolver_verbosity_);
            break;
        case KAMG:
#ifdef HAS_DUNE_FAST_AMG
            res = solveKAMG(A, x, b, linsolver_residual_tolerance_, maxit, linsolver_verbosity_);
#else
            throw std::runtime_error("KAMG not supported with this version of DUNE");
#endif
            break;
        case FastAMG:
#ifdef HAS_DUNE_FAST_AMG
            res = solveFastAMG(A, x, b, linsolver_residual_tolerance_, maxit, linsolver_verbosity_);
#else
	    if(linsolver_verbosity_)
	      std::cerr<<"Fast AMG is not available; falling back to CG preconditioned with the normal one"<<std::endl;
	    res = solveCG_AMG(A, x, b, linsolver_residual_tolerance_, maxit, linsolver_verbosity_);
#endif
            break;
        case BiCGStab_ILU0:
            res = solveBiCGStab_ILU0(A, x, b, linsolver_residual_tolerance_, maxit, linsolver_verbosity_);
            break;
        default:
            std::cerr << "Unknown linsolver_type: " << int(linsolver_type_) << '\n';
            throw std::runtime_error("Unknown linsolver_type");
        }
        std::copy(x.begin(), x.end(), solution);
        return res;
    }