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;
}
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;
}