bool AtomExtruder::extrudeAtoms(
common::Structure & structure,
const size_t maxIterations,
const double tolerance) const
{
const size_t numAtoms = structure.getNumAtoms();
::std::vector<common::Atom *> atomsWithRadii;
for(size_t i = 0; i < numAtoms; ++i)
{
common::Atom & atom = structure.getAtom(i);
if(atom.getRadius() != 0.0)
{
atomsWithRadii.push_back(&atom);
}
}
// Calculate seaparation matrix
::arma::mat sepSqMtx(atomsWithRadii.size(), atomsWithRadii.size());
double radius1;
for(size_t row = 0; row < atomsWithRadii.size(); ++row)
{
radius1 = atomsWithRadii[row]->getRadius();
for(size_t col = row; col < atomsWithRadii.size(); ++col)
{
sepSqMtx(row, col) = radius1 + atomsWithRadii[col]->getRadius();
sepSqMtx(row, col) *= sepSqMtx(row, col);
}
}
sepSqMtx = ::arma::symmatu(sepSqMtx);
return extrudeAtoms(structure.getDistanceCalculator(), atomsWithRadii, sepSqMtx, tolerance, maxIterations);
}
VoronoiSlabGenerator::Slab::SlabData::SlabData(
const common::Structure & structure) :
distCalc(structure.getDistanceCalculator()), unitCell(
structure.getUnitCell())
{
}
bool
LennardJones::evaluate(const common::Structure & structure,
SimplePairPotentialData & data) const
{
using namespace utility::cart_coords_enum;
using ::std::vector;
using ::std::pow;
using ::std::sqrt;
double rSq;
double prefactor;
double sigmaOModR, invRM, invRN;
double dE, modR, modF, interaction;
size_t speciesI, speciesJ; // Species indices
::arma::vec3 f; // Displacement and force vectors
::arma::vec3 posI, posJ; // Position vectors
resetAccumulators(data);
vector< ::arma::vec3> imageVectors;
const common::DistanceCalculator & distCalc =
structure.getDistanceCalculator();
bool problemDuringCalculation = false;
// Loop over all particle pairs (including self-interaction)
for(size_t i = 0; i < data.numParticles; ++i)
{
if(data.species[i] == DataType::IGNORE_ATOM)
continue;
else
speciesI = static_cast< size_t>(data.species[i]);
posI = data.pos.col(i);
for(size_t j = i; j < data.numParticles; ++j)
{
if(data.species[j] == DataType::IGNORE_ATOM)
continue;
else
speciesJ = static_cast< size_t>(data.species[j]);
posJ = data.pos.col(j);
imageVectors.clear();
if(!distCalc.getVecsBetween(posI, posJ, rCutoff(speciesI, speciesJ),
imageVectors, MAX_INTERACTION_VECTORS, MAX_CELL_MULTIPLES))
{
// We reached the maximum number of interaction vectors so indicate that there was a problem
problemDuringCalculation = true;
}
// Used as a prefactor depending if the particles i and j are in fact the same
interaction = (i == j) ? 0.5 : 1.0;
prefactor = 4.0 * myEpsilon(speciesI, speciesJ);
BOOST_FOREACH(const ::arma::vec & r, imageVectors)
{
// Get the distance squared
rSq = dot(r, r);
// Check that distance isn't near the 0 as this will cause near-singular values
if(rSq > MIN_SEPARATION_SQ)
{
modR = sqrt(rSq);
sigmaOModR = mySigma(speciesI, speciesJ) / modR;
invRN = pow(sigmaOModR, myN);
// Deal with special case where N is 2 times M avoiding second pow call
invRM = myM == 2.0 * myN ? invRN * invRN : pow(sigmaOModR, myM);
invRN *= myBeta(speciesI, speciesJ);
// Calculate the energy delta
dE = prefactor * (invRM - invRN) - eShift(speciesI, speciesJ)
+ (modR - rCutoff(speciesI, speciesJ))
* fShift(speciesI, speciesJ);
// Magnitude of the force
modF = prefactor * (myM * invRM - myN * invRN) / modR
- fShift(speciesI, speciesJ);
f = modF / modR * r;
// Make sure we get energy/force correct for self-interaction
f *= interaction;
dE *= interaction;
// Update system values
// energy
data.internalEnergy += dE;
// force
data.forces.col(i) -= f;
if(i != j)
data.forces.col(j) += f;
// stress, diagonal is element wise multiplication of force and position
// vector components
data.stressMtx.diag() -= f % r;
data.stressMtx(Y, Z) -= 0.5 * (f(Y) * r(Z) + f(Z) * r(Y));
data.stressMtx(Z, X) -= 0.5 * (f(Z) * r(X) + f(X) * r(Z));
data.stressMtx(X, Y) -= 0.5 * (f(X) * r(Y) + f(Y) * r(X));
}
}
}
}