bool LinearSolver::solve(VECTOR & x, const VECTOR & b)
{
SPAR_MAT * A = NULL;
rhs_ = &b;
initialized_ = false;
initialize();
if (num_unknowns() == 0) {
set_fixed_values(x);
return true;
}
const VECTOR & r = *b_;
if (solverType_ == ITERATIVE_SOLVE_SYMMETRIC) {
if (parallel_) {
A = new PAR_SPAR_MAT(LammpsInterface::instance()->world(), *matrixSparse_);
}
else {
A = new SPAR_MAT(*matrixSparse_);
}
DIAG_MAT & PC = matrixDiagonal_;
int niter = maxIterations_;
double tol = tol_;
int convergence = CG(*A, x, r, PC, niter, tol);// CG changes niter, tol
if (convergence>0) {
stringstream ss;
ss << "CG solve did not converge,";
ss << " iterations: " << niter;
ss << " residual: " << tol;
throw ATC_Error(ss.str());
}
}
else if (solverType_ == ITERATIVE_SOLVE) {
if (parallel_) {
A = new PAR_SPAR_MAT(LammpsInterface::instance()->world(), *matrixSparse_);
}
else {
A = new SPAR_MAT(*matrixSparse_);
}
const DIAG_MAT & PC = matrixDiagonal_;
int iterations = maxIterations_;
int restarts = maxRestarts_;
double tol = tol_;
DENS_MAT H(maxRestarts_+1, maxRestarts_);
DENS_VEC xx(nVariables_);
DENS_VEC bb;
bb = b;
int convergence = GMRES(*A, xx, bb, PC, H, restarts, iterations, tol);
if (convergence>0) {
stringstream ss;
ss << "GMRES greens_function solve did not converge,";
ss << " iterations: " << iterations;
ss << " residual: " << tol;
throw ATC_Error(ss.str());
}
x.copy(xx.ptr(),xx.nRows());
}
else { // DIRECT_SOLVE
const DENS_MAT & invA = matrixInverse_;
if (constraintHandlerType_ == CONDENSE_CONSTRAINTS) {
DENS_MAT xx = invA*r;
int i = 0;
set<int>::const_iterator itr;
for (itr = freeSet_.begin(); itr != freeSet_.end(); itr++,i++) {
int ii = *itr;
x(ii) = xx(i,0);
}
set_fixed_values(x);
}
else {
DENS_VEC xx = invA*r;
for (int i = 0; i < xx.nRows(); i++) {
x(i) = xx(i);
}
}
}
delete A;
return true;
}
