void LinearSolver::greens_function(int I, VECTOR & G_I)
{
SPAR_MAT * A = NULL;
initialize_matrix();
initialize_inverse();
G_I.reset(nVariables_);
VECTOR & x = G_I;
if (solverType_ == ITERATIVE_SOLVE_SYMMETRIC) {
DENS_VEC b(nVariables_); b = 0.0; b(I) = 1.0;
if (parallel_) {
A = new PAR_SPAR_MAT(LammpsInterface::instance()->world(), *matrixSparse_);
}
else {
A = new SPAR_MAT(*matrixSparse_);
}
const DIAG_MAT & PC = matrixDiagonal_;
int niter = maxIterations_;
double tol = tol_;
int convergence = CG(*A, x, b, PC, niter, tol);
if (convergence>0) {
stringstream ss;
ss << "CG greens_function solve did not converge,";
ss << " iterations: " << niter;
ss << " residual: " << tol;
throw ATC_Error(ss.str());
}
}
else if (solverType_ == ITERATIVE_SOLVE) {
DENS_VEC b(nVariables_); b = 0.0; b(I) = 1.0;
// VECTOR & bb = b;
if (parallel_) {
A = new PAR_SPAR_MAT(LammpsInterface::instance()->world(), *matrixSparse_);
}
else {
A = new SPAR_MAT(*matrixSparse_);
}
// const DENS_MAT A = matrixSparse_->dense_copy();
const DIAG_MAT & PC = matrixDiagonal_;
int iterations = maxIterations_;
int restarts = maxRestarts_;
double tol = tol_;
DENS_MAT H(maxRestarts_+1, maxRestarts_);
DENS_VEC xx(nVariables_);
int convergence = GMRES(*A, xx, b, 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 {
const DENS_MAT & invA = matrixInverse_;
if (constraintHandlerType_ == CONDENSE_CONSTRAINTS) {
set<int>::const_iterator itr;
for (itr = fixedSet_.begin(); itr != fixedSet_.end(); itr++) {
int ii = *itr;
x(ii) = 0;
}
itr = freeSet_.find(I);
if (itr !=freeSet_.end() ) {
int j = freeGlobalToCondensedMap_[I];
int i = 0;
for (itr = freeSet_.begin(); itr != freeSet_.end(); itr++,i++) {
int ii = *itr;
x(ii) = invA(j,i);
}
}
}
else {
for (int i = 0; i < nVariables_; ++i) x(i) = invA(I,i);
}
}
delete A;
}
