boost::tuple<int, operator_container_t::iterator, operator_container_t::iterator>
pick_up_pair(R &rng,
const operator_container_t &c_operators,
const operator_container_t &a_operators,
int flavor_ins,
int flavor_rem,
double t1,
double t2,
double distance,
double BETA) {
namespace bll = boost::lambda;
typedef operator_container_t::iterator it_t;
//get views to operators in the window
double tau_low = std::min(t1, t2);
double tau_high = std::max(t1, t2);
std::pair<operator_container_t::iterator, operator_container_t::iterator>
crange = c_operators.range(tau_low <= bll::_1, bll::_1 <= tau_high);
std::pair<operator_container_t::iterator, operator_container_t::iterator>
arange = a_operators.range(tau_low <= bll::_1, bll::_1 <= tau_high);
typedef std::list<std::pair<it_t, it_t> > pairs_t;
pairs_t pairs;
int num_pairs = 0;
for (operator_container_t::iterator it_c = crange.first; it_c != crange.second; ++it_c) {
if (it_c->flavor() != flavor_ins) {
continue;
}
for (operator_container_t::iterator it_a = arange.first; it_a != arange.second; ++it_a) {
if (it_a->flavor() != flavor_rem) {
continue;
}
if (std::abs(it_c->time() - it_a->time()) <= distance) {
pairs.push_back(std::make_pair(it_c, it_a));
++num_pairs;
}
}
}
if (num_pairs > 0) {
int pos = (int) (rng() * num_pairs);
pairs_t::iterator it_p = pairs.begin();
std::advance(it_p, pos);
return boost::make_tuple(num_pairs, (*it_p).first, (*it_p).second);
} else {
return boost::make_tuple(0, c_operators.end(), a_operators.end());
}
}
void construct_blas_matrix(MAT & M, const operator_container_t &creation_operators,
const operator_container_t &annihilation_operators, double BETA, const HYB & F)
{
int N = creation_operators.size();
M.resize(N, N);
int row = -1;
int column = -1;
for (operator_container_t::iterator ita = annihilation_operators.begin(); ita != annihilation_operators.end(); ita++) {
row++;
for (operator_container_t::iterator itc = creation_operators.begin(); itc != creation_operators.end(); itc++) {
column++;
double argument = ita->time() - itc->time();
double sign = 1;
if (argument < 0) {
argument += BETA;
sign = -1;
}
M(row, column) = interpolate_F(argument, BETA, F[ita->flavor()][itc->flavor()]) * sign;
}
column = -1;
}
}
inline
double make_set_impl(const operator_container_t &annihilation_operators, double BETA, double dtau, std::set<boost::tuple<double,int,double> >& annset) {
int row = -1;
annset.clear();
int num_op_shifted = 0;
double perm = 1.0;
for (operator_container_t::iterator ita = annihilation_operators.begin(); ita != annihilation_operators.end(); ita++) {
row++;
double p = 1.0;
double t = ita->time() + dtau;
if (t > BETA) {
t -= BETA;
p = -1.0;
perm *= -1;
++num_op_shifted;
}
annset.insert(boost::make_tuple(t,row,p));
}
return perm * (
((annihilation_operators.size()-num_op_shifted)*num_op_shifted)%2==0 ? 1 : -1
);
}