mc_weight_type attempt() {
#ifdef DEBUG
std::cout << "I AM IN attempt for Move" << std::endl;
std::cout << "CONFIG BEFORE: " << Config.DT << std::endl;
for (int a = 0; a < Config.Na; ++a) print_det(Config.dets[a]);
#endif
// find an operator (anyone) to be moved.
// to do this, I go over the DT trace
const int L(Config.DT.Length());
if (L==0) return 0;
const int N(Random(L));
// I go over the trace to find the op oldOpref
// and then I get its info
Configuration::OP_REF oldOpref = Config.DT.OpRef_begin();
for (int i=0; i<N; ++i, ++oldOpref) {}
int a = Config.info[oldOpref->Op->Number].a;
int Nalpha = Config.COps[a].size();
bool isdagger = Config.info[oldOpref->Op->Number].dagger;
double oldtau = oldOpref->tau;
// chose the new alpha (this is done here for compatibility)
int newalpha = Random(Nalpha);
int num;
double tR, tL;
det = Config.dets[a];
Configuration::DET_TYPE::Cdagger_iterator itCdag = det->Cdagger_begin();
Configuration::DET_TYPE::C_iterator itC = det->C_begin();
if (det->size() > 1) {
// find the C and Cdag operators at the right of oldOpref (at smaller times)
// it might be Cdagger_end() or C_end()
// also get the number num of oldOpref in the det
num = 0;
while ( (itCdag != det->Cdagger_end()) && (itCdag->tau >= oldtau) ) {++itCdag; if(isdagger) ++num;}
while ( (itC != det->C_end()) && (itC->tau >= oldtau) ) {++itC; if(!isdagger) ++num;}
// find the times of the operator at the right of oldOpref with cyclicity
// then deduce the closest one and put its distance to oldOpref in tR
double tRdag = (itCdag != det->Cdagger_end() ? (*itCdag)->tau : det->Cdagger_begin()->tau);
double tRnodag = (itC != det->C_end() ? (*itC)->tau : det->C_begin()->tau);
tR = std::min(Config.CyclicOrientedTimeDistance(oldtau - tRdag), Config.CyclicOrientedTimeDistance(oldtau - tRnodag));
// move itCdag and itC to the operators on the left with cyclicity
// find their times and deduce the closest one with distance tL
if (isdagger) --itCdag; else --itC;
if (itCdag != det->Cdagger_begin()) --itCdag; else itCdag = --det->Cdagger_end();
if (itC != det->C_begin()) --itC; else itC = --det->C_end();
tL = std::min(Config.CyclicOrientedTimeDistance((*itCdag)->tau - oldtau), Config.CyclicOrientedTimeDistance((*itC)->tau - oldtau));
} else {
num = 1;
tR = (isdagger ? Config.CyclicOrientedTimeDistance(oldtau - (*itC)->tau) : Config.CyclicOrientedTimeDistance(oldtau - (*itCdag)->tau));
tL = (isdagger ? Config.CyclicOrientedTimeDistance((*itC)->tau - oldtau) : Config.CyclicOrientedTimeDistance((*itCdag)->tau - oldtau));
}
// the new operator newOp with a new chosen alpha
double newtau = Config.CyclicOrientedTimeDistance(oldtau - tR + Random(tL + tR - 2*ctqmc_utils::EPSILON) + ctqmc_utils::EPSILON);
const Hloc::Operator * newOp;
newOp = (isdagger ? Config.CdagOps[a][newalpha] : Config.COps[a][newalpha]);
// remove oldOpref and insert newOp in the Trace
bool ok;
Configuration::OP_REF Op;
std::tie(ok,Op) = Config.DT.insert_and_remove_One_Operator(oldOpref, newtau, *newOp);
if (!ok) return 0;
// in the following we want to see if we need to roll the det
roll_matrix = Configuration::DET_TYPE::None;
// check if we went through \tau = 0 or \tau = \beta
if (newtau - oldtau > tL) roll_matrix = (isdagger ? Configuration::DET_TYPE::Down : Configuration::DET_TYPE::Right);
if (oldtau - newtau > tR) roll_matrix = (isdagger ? Configuration::DET_TYPE::Up : Configuration::DET_TYPE::Left);
// acceptance probability
mc_weight_type p = Config.DT.ratioNewTrace_OldTrace() * (isdagger ? det->try_change_row(num-1,Op) : det->try_change_col(num-1,Op));
#ifdef DEBUG
std::cout << "oldtau, tR, tL, newtau: " << oldtau << " " << tR << " " << tL << " " << newtau << endl;
std::cout << "Trace Ratio: " << Config.DT.ratioNewTrace_OldTrace() << std::endl;
std::cout << "Det Ratio: " << p/mc_weight_type(Config.DT.ratioNewTrace_OldTrace()) << std::endl;
std::cout << "Rate: " << p << std::endl;
std::cout << "CONFIG AFTER: " << Config.DT << std::endl;
for (int a = 0; a < Config.Na; ++a) print_det(Config.dets[a]);
#endif
return p;
}
