float prevCODist {CalculateAtomicDistances(Donor.prevResi->getIndex(backboneAtomTypes::AtomC), Donor.prevResi->getIndex(backboneAtomTypes::AtomO), fr, pbc)};
for (int i{XX}; i <= ZZ; ++i){
float prevCO = fr.x[Donor.prevResi->getIndex(backboneAtomTypes::AtomC)][i] - fr.x[Donor.prevResi->getIndex(backboneAtomTypes::AtomO)][i];
float prevCODist {CalculateAtomicDistances(Donor.prevResi->getIndex(backboneAtomTypes::AtomC), Donor.prevResi->getIndex(backboneAtomTypes::AtomO), fr, pbc)};
for (int i{XX}; i <= ZZ; ++i){
float prevCO = fr.x[Donor.prevResi->getIndex(backboneAtomTypes::AtomC)][i] - fr.x[Donor.prevResi->getIndex(backboneAtomTypes::AtomO)][i];