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//
// Created by Santosh Putta, Nov 2006
//
#ifndef __RD_FOURTHDIMCONTRIB_H__
#define __RD_FOURTHDIMCONTRIB_H__
#include <RDGeneral/Invariant.h>
#include <ForceField/Contrib.h>
#include <ForceField/ForceField.h>
namespace DistGeom {
//! A term used in penalizing chirality violations
//!
class FourthDimContrib : public ForceFields::ForceFieldContrib {
public:
FourthDimContrib() : d_idx(0), d_weight(0.0){};
//! Constructor
/*!
\param owner pointer to the owning ForceField
\param idx the index of the atom to be considered
\param weight (optional) the weight to be used for this contrib
*/
FourthDimContrib(ForceFields::ForceField *owner, unsigned int idx,
double weight)
: d_idx(idx), d_weight(weight) {
PRECONDITION(owner, "bad force field");
PRECONDITION(owner->dimension() == 4, "force field has wrong dimension");
dp_forceField = owner;
};
//! return the contribution of this contrib to the energy of a given state
double getEnergy(double *pos) const {
PRECONDITION(dp_forceField, "no owner");
PRECONDITION(dp_forceField->dimension() == 4,
"force field has wrong dimension");
PRECONDITION(pos, "bad vector");
unsigned int pid = d_idx * dp_forceField->dimension() + 3;
return d_weight * pos[pid] * pos[pid];
}
//! calculate the contribution of this contrib to the gradient at a given
//state
void getGrad(double *pos, double *grad) const {
PRECONDITION(dp_forceField, "no owner");
PRECONDITION(dp_forceField->dimension() == 4,
"force field has wrong dimension");
PRECONDITION(pos, "bad vector");
unsigned int pid = d_idx * dp_forceField->dimension() + 3;
grad[pid] += d_weight * pos[pid];
}
virtual FourthDimContrib *copy() const {
return new FourthDimContrib(*this);
};
private:
unsigned int d_idx;
double d_weight;
};
}
#endif
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