Ejemplo n.º 1
0
   /*
   * Evaluate Rosenbluth weight, and add to accumulator.
   */
   void McChemicalPotential::sample(long iStep)
   {
      if (isAtInterval(iStep))  {

         Species* speciesPtr;
         Molecule* molPtr;
         Molecule::BondIterator bondIter;
         Atom* endPtr;
         double w;
         double rosenbluth = 1;
         double de;
         double e = 0;

         speciesPtr = &(simulation().species(speciesId_));

         // Pop a new molecule off the species reservoir
         molPtr = &(speciesPtr->reservoir().pop());
         system().addMolecule(*molPtr);

         // Loop over molecule growth trials
         for (int i = 0; i < nMoleculeTrial_; i++) {

            // Pick a random position for the first atom
            endPtr = &molPtr->atom(0);
            boundary().randomPosition(random(), endPtr->position());

            e = system().pairPotential().atomEnergy(*endPtr);
            rosenbluth = boltzmann(e);
            system().pairPotential().addAtom(*endPtr);

            for (molPtr->begin(bondIter); bondIter.notEnd(); ++bondIter) {
                addEndAtom(&(bondIter->atom(1)), &(bondIter->atom(0)), bondIter->typeId(), w, de);
                e += de;
                rosenbluth *= w;
                system().pairPotential().addAtom(bondIter->atom(1));
            }

            rosenbluth = rosenbluth / pow(nTrial_,molPtr->nAtom()-1);
            accumulator_.sample(rosenbluth, outputFile_);

            system().pairPotential().deleteAtom(*endPtr);
            for (molPtr->begin(bondIter); bondIter.notEnd(); ++bondIter) {
                system().pairPotential().deleteAtom(bondIter->atom(1));
            }
         }

         // Return additional molecule to reservoir
         system().removeMolecule(*molPtr);
         speciesPtr->reservoir().push(*molPtr);
      }

   }
Ejemplo n.º 2
0
 void HoomdMove::addBonds()
 {
    // Loop over bonds and initialize them
    int iSpec;
    System::MoleculeIterator molIter;
    Molecule::BondIterator bondIter;
    for (iSpec=0; iSpec < simulation().nSpecies(); ++iSpec) {
       for (system().begin(iSpec, molIter); molIter.notEnd(); ++molIter) {
          for (molIter->begin(bondIter); bondIter.notEnd(); ++bondIter) {
             ::Bond bond(bondIter->typeId(),
                         bondIter->atom(0).id(),
                         bondIter->atom(1).id());
             bondDataSPtr_->addBond(bond);
           }
       }
    } 
 }