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#ifndef CBEAM_H
#define CBEAM_H
#include <iostream>
#include <cstdlib>
#include "CbPotential.h"
#include "LammpsInterface.h"
#include "MANYBODY/pair_eam.h"
namespace ATC
{
/**
* @class CbEam
* @brief Class for computing Cauchy-Born quantities for an Embeded-Atom Method material
* (A factor of one-half is already included to split the
* bond energy between atoms)
*/
class CbEam : public CbPotential
{
public:
//! Constructor
CbEam(void) : CbPotential(Interactions(PAIRWISE,EAM)) {
// get pointer to lammps' pair_eam object
lammps_eam = ATC::LammpsInterface::instance()->pair_eam();
nrho = &lammps_eam->nrho;
nr = &lammps_eam->nr;
nfrho = &lammps_eam->nfrho;
nrhor = &lammps_eam->nrhor;
nz2r = &lammps_eam->nz2r;
type2frho = lammps_eam->type2frho;
type2rhor = lammps_eam->type2rhor;
type2z2r = lammps_eam->type2z2r;
dr = &lammps_eam->dr;
rdr = &lammps_eam->rdr;
drho = &lammps_eam->drho;
rdrho = &lammps_eam->rdrho;
rhor_spline = &lammps_eam->rhor_spline;
frho_spline = &lammps_eam->frho_spline;
z2r_spline = &lammps_eam->z2r_spline;
cutmax = &lammps_eam->cutmax;
}
//! Returns the cutoff readius of the EAM potential functions rho and z2r.
double cutoff_radius() const { return *cutmax; }
//! Returns the EAM pair energy
double phi(const double &r) const
{
double p = r*(*rdr) + 1.0;
int m = static_cast<int> (p);
m = MIN(m,(*nr)-1);
p -= m;
p = MIN(p,1.0);
// for now, assume itype = jtype = 1
double *coeff = (*z2r_spline)[type2z2r[1][1]][m];
double z2 = ((coeff[3]*p + coeff[4])*p + coeff[5])*p + coeff[6];
return z2/r;
}
//! Returns the first derivative of the pair energy.
double phi_r(const double &r) const
{
double p = r*(*rdr) + 1.0;
int m = static_cast<int> (p);
m = MIN(m,(*nr)-1);
p -= m;
p = MIN(p,1.0);
// for now, assume itype = jtype = 1
double *coeff = (*z2r_spline)[type2z2r[1][1]][m];
double z2 = ((coeff[3]*p + coeff[4])*p + coeff[5])*p + coeff[6];
double z2p = (coeff[0]*p + coeff[1])*p + coeff[2];
return (1.0/r)*(z2p-z2/r);
}
//! Returns the second derivative of the pair energy.
double phi_rr(const double &r) const
{
double p = r*(*rdr) + 1.0;
int m = static_cast<int> (p);
m = MIN(m,(*nr)-1);
p -= m;
p = MIN(p,1.0);
// for now, assume itype = jtype = 1
double *coeff = (*z2r_spline)[type2z2r[1][1]][m];
double z2 = ((coeff[3]*p + coeff[4])*p + coeff[5])*p + coeff[6];
double z2p = (coeff[0]*p + coeff[1])*p + coeff[2];
double z2pp = (*rdr)*(2.0*coeff[0]*p + coeff[1]);
return (1.0/r)*(z2pp-2.0*z2p/r+2.0*z2/(r*r));
}
//! Returns the third derivative of the pair energy.
double phi_rrr(const double &r) const
{
double p = r*(*rdr) + 1.0;
int m = static_cast<int> (p);
m = MIN(m,(*nr)-1);
p -= m;
p = MIN(p,1.0);
// for now, assume itype = jtype = 1
double *coeff = (*z2r_spline)[type2z2r[1][1]][m];
double z2 = ((coeff[3]*p + coeff[4])*p + coeff[5])*p + coeff[6];
double z2p = (coeff[0]*p + coeff[1])*p + coeff[2];
double z2pp = (*rdr)*(2.0*coeff[0]*p + coeff[1]);
double z2ppp = (*rdr)*(*rdr)*2.0*coeff[0];
return (1.0/r)*(z2ppp-3.0*z2pp/r+6.0*z2p/(r*r)-6.0*z2/(r*r*r));
}
//! Returns the EAM atomic charge density.
double rho(const double &r) const
{
double p = r*(*rdr) + 1.0;
int m = static_cast<int> (p);
m = MIN(m,(*nr)-1);
p -= m;
p = MIN(p,1.0);
// for now, assume itype = jtype = 1
double *coeff = (*rhor_spline)[type2rhor[1][1]][m];
return (((coeff[3]*p + coeff[4])*p + coeff[5])*p + coeff[6]);
}
//! Returns the first derivative of the atomic charge density.
double rho_r(const double &r) const
{
double p = r*(*rdr) + 1.0;
int m = static_cast<int> (p);
m = MIN(m,(*nr)-1);
p -= m;
p = MIN(p,1.0);
// for now, assume itype = jtype = 1
double *coeff = (*rhor_spline)[type2rhor[1][1]][m];
return ((coeff[0]*p + coeff[1])*p + coeff[2]);
}
//! Returns the second derivative of the atomic charge density.
double rho_rr(const double &r) const
{
double p = r*(*rdr) + 1.0;
int m = static_cast<int> (p);
m = MIN(m,(*nr)-1);
p -= m;
p = MIN(p,1.0);
// for now, assume itype = jtype = 1
double *coeff = (*rhor_spline)[type2rhor[1][1]][m];
return ((*rdr)*(2.0*coeff[0]*p + coeff[1]));
}
//! Returns the third derivative of the atomic charge density.
double rho_rrr(const double &r) const
{
double p = r*(*rdr) + 1.0;
int m = static_cast<int> (p);
m = MIN(m,(*nr)-1);
p -= m;
p = MIN(p,1.0);
// for now, assume itype = jtype = 1
double *coeff = (*rhor_spline)[type2rhor[1][1]][m];
return ((*rdr)*(*rdr)*2.0*coeff[0]);
}
//! Returns the EAM embedding energy.
double F(const double &p) const
{
double q = p*(*rdrho) + 1.0;
int m = static_cast<int> (q);
m = MIN(m,(*nrho)-1);
q -= m;
q = MIN(q,1.0);
// for now, assume itype = 1
double *coeff = (*frho_spline)[type2frho[1]][m];
return (((coeff[3]*q + coeff[4])*q + coeff[5])*q + coeff[6]);
}
//! Returns the first derivative of the embedding energy.
double F_p(const double &p) const
{
double q = p*(*rdrho) + 1.0;
int m = static_cast<int> (q);
m = MIN(m,(*nrho)-1);
q -= m;
q = MIN(q,1.0);
// for now, assume itype = 1
double *coeff = (*frho_spline)[type2frho[1]][m];
return ((coeff[0]*q + coeff[1])*q + coeff[2]);
}
//! Returns the second derivative of the atomic charge density.
double F_pp(const double &p) const
{
double q = p*(*rdrho) + 1.0;
int m = static_cast<int> (q);
m = MIN(m,(*nrho)-1);
q -= m;
q = MIN(q,1.0);
// for now, assume itype = 1
double *coeff = (*frho_spline)[type2frho[1]][m];
return ((*rdrho)*(2.0*coeff[0]*q + coeff[1]));
}
//! Returns the third derivative of the atomic charge density.
double F_ppp(const double &p) const
{
double q = p*(*rdrho) + 1.0;
int m = static_cast<int> (q);
m = MIN(m,(*nrho)-1);
q -= m;
q = MIN(q,1.0);
// for now, assume itype = 1
double *coeff = (*frho_spline)[type2frho[1]][m];
return ((*rdrho)*(*rdrho)*2.0*coeff[0]);
}
int *nrho,*nr,*nfrho,*nrhor,*nz2r;
int *type2frho,**type2rhor,**type2z2r;
double *cutmax;
double *dr,*rdr,*drho,*rdrho;
double ****rhor_spline,****frho_spline,****z2r_spline;
LAMMPS_NS::PairEAM* lammps_eam;
};
}
#endif
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