void PolyInterpMixin<time>::fas(time dt, shared_ptr<ISweeper<time>> dst,
shared_ptr<const ISweeper<time>> src)
{
auto& crse = pfasst::encap::as_encap_sweeper(dst);
auto& fine = pfasst::encap::as_encap_sweeper(src);
auto const ncrse = crse.get_nodes().size(); assert(ncrse >= 1);
auto const nfine = fine.get_nodes().size(); assert(nfine >= 1);
auto crse_factory = crse.get_factory();
auto fine_factory = fine.get_factory();
EncapVecT crse_int(ncrse), fine_int(nfine), rstr_int(ncrse);
for (size_t m = 0; m < ncrse; m++) { crse_int[m] = crse_factory->create(solution); }
for (size_t m = 0; m < ncrse; m++) { rstr_int[m] = crse_factory->create(solution); }
for (size_t m = 0; m < nfine; m++) { fine_int[m] = fine_factory->create(solution); }
// compute '0 to node' integral on the coarse level
crse.integrate(dt, crse_int);
// compute '0 to node' integral on the fine level
fine.integrate(dt, fine_int);
// restrict '0 to node' fine integral
int trat = (int(nfine) - 1) / (int(ncrse) - 1);
for (size_t m = 0; m < ncrse; m++) {
this->restrict(rstr_int[m], fine_int[m * trat]);
}
// compute 'node to node' tau correction
EncapVecT tau(ncrse), rstr_and_crse(2 * ncrse);
// Attention: tau is getting filled with pointers to the crse's member
for (size_t m = 0; m < ncrse; m++) { tau[m] = crse.get_tau(m); }
for (size_t m = 0; m < ncrse; m++) { rstr_and_crse[m] = rstr_int[m]; }
for (size_t m = 0; m < ncrse; m++) { rstr_and_crse[ncrse + m] = crse_int[m]; }
if (fmat.rows() == 0) {
fmat.resize(ncrse, 2 * ncrse);
fmat.fill(0.0);
for (size_t m = 0; m < ncrse; m++) {
fmat(m, m) = 1.0;
fmat(m, ncrse + m) = -1.0;
// subtract 0-to-(m-1) FAS so resulting FAS is (m-1)-to-m FAS,
// which will be required in the sweeper logic
for (size_t n = 0; n < m; n++) {
fmat(m, n) = -1.0;
fmat(m, ncrse + n) = 1.0;
}
}
}
tau[0]->mat_apply(tau, 1.0, fmat, rstr_and_crse, true);
}
virtual void fas(time dt, shared_ptr<ISweeper<time>> dst,
shared_ptr<const ISweeper<time>> src) override
{
auto& crse = pfasst::encap::as_encap_sweeper(dst);
auto& fine = pfasst::encap::as_encap_sweeper(src);
auto const ncrse = crse.get_nodes().size(); assert(ncrse >= 1);
auto const nfine = fine.get_nodes().size(); assert(nfine >= 1);
auto crse_factory = crse.get_factory();
auto fine_factory = fine.get_factory();
EncapVecT crse_int(ncrse), fine_int(nfine), rstr_int(ncrse);
for (size_t m = 0; m < ncrse; m++) { crse_int[m] = crse_factory->create(solution); }
for (size_t m = 0; m < ncrse; m++) { rstr_int[m] = crse_factory->create(solution); }
for (size_t m = 0; m < nfine; m++) { fine_int[m] = fine_factory->create(solution); }
// compute '0 to node' integral on the coarse level
crse.integrate(dt, crse_int);
// compute '0 to node' integral on the fine level
fine.integrate(dt, fine_int);
// restrict '0 to node' fine integral
int trat = (int(nfine) - 1) / (int(ncrse) - 1);
for (size_t m = 0; m < ncrse; m++) {
this->restrict(rstr_int[m], fine_int[m * trat]);
}
// compute 'node to node' tau correction
EncapVecT tau(ncrse), rstr_and_crse(2 * ncrse);
for (size_t m = 0; m < ncrse; m++) { tau[m] = crse.get_tau(m); }
for (size_t m = 0; m < ncrse; m++) { rstr_and_crse[m] = rstr_int[m]; }
for (size_t m = 0; m < ncrse; m++) { rstr_and_crse[ncrse + m] = crse_int[m]; }
if (fmat.rows() == 0) {
fmat.resize(ncrse, 2 * ncrse);
fmat.fill(0.0);
for (size_t m = 0; m < ncrse; m++) {
fmat(m, m) = 1.0;
fmat(m, ncrse + m) = -1.0;
for (size_t n = 0; n < m; n++) {
fmat(m, n) = -1.0;
fmat(m, ncrse + n) = 1.0;
}
}
}
tau[0]->mat_apply(tau, 1.0, fmat, rstr_and_crse, true);
}