double DebyeWallerPeakWidth::calculate(const BaseBondGenerator& bnds) const
{
using diffpy::mathutils::GAUSS_SIGMA_TO_FWHM;
double msdval = bnds.msd();
double rv = (msdval < 0.0) ? 0.0 : GAUSS_SIGMA_TO_FWHM * sqrt(msdval);
return rv;
}
void BVSCalculator::addPairContribution(const BaseBondGenerator& bnds,
int summationscale)
{
const string& a0 = mstructure_cache.baresymbols[bnds.site0()];
const string& a1 = mstructure_cache.baresymbols[bnds.site1()];
int v0 = mstructure_cache.valences[bnds.site0()];
int v1 = mstructure_cache.valences[bnds.site1()];
const BVParametersTable& bvtb = *(this->getBVParamTable());
const BVParam& bp = bvtb.lookup(a0, v0, a1, v1);
// do nothing if there are no bond parameters for this pair
if (&bp == &bvtb.none()) return;
double valencehalf = bp.bondvalence(bnds.distance()) / 2.0;
int pm0 = (v0 >= 0) ? 1 : -1;
int pm1 = (v1 >= 0) ? 1 : -1;
const double& o0 = mstructure->siteOccupancy(bnds.site0());
const double& o1 = mstructure->siteOccupancy(bnds.site1());
mvalue[bnds.site0()] += summationscale * pm0 * valencehalf * o1;
mvalue[bnds.site1()] += summationscale * pm1 * valencehalf * o0;
}
void PairQuantity::configureBondGenerator(BaseBondGenerator& bnds) const
{
bnds.setRmin(this->getRmin());
bnds.setRmax(this->getRmax());
}
// define contribution from a pair of atoms. mvalue is a reference
// to the internal array of result values.
void addPairContribution(const BaseBondGenerator& bnds, int sumscale)
{
double rij = bnds.distance();
double ljij = 4 * (pow(rij, -12) - pow(rij, -6));
mvalue[0] += sumscale * ljij / 2.0;
}
void DebyePDFCalculator::configureBondGenerator(BaseBondGenerator& bnds) const
{
bnds.setRmin(this->rcalclo());
bnds.setRmax(this->rcalchi());
}
void BVSCalculator::configureBondGenerator(BaseBondGenerator& bnds) const
{
bnds.setRmax(this->getRmaxUsed());
}
