void Jastrow_threebody_piece_diffspin::getParmDeriv(const Array3 <doublevar> & eibasis,
const Array3 <doublevar> & eebasis,
Parm_deriv_return & deriv) {
//cout << "Jastrow_threebody_piece_diffspin::getParmDeriv" << endl;
assert(eibasis.GetDim(1) >= parm_centers.GetDim(0));
int natoms=parm_centers.GetDim(0);
int nelectrons=eebasis.GetDim(0);
const doublevar tiny=1e-14;
//cout << "updateLap " << endl;
for(int at=0; at < natoms; at++) {
int p=parm_centers(at);
for(int i=0; i< _nparms(p); i++) {
int k=klm(i,0), el=klm(i,1), m=klm(i,2);
for(int e=0; e< nelectrons; e++) {
if(fabs(eibasis(e,at,k)) > tiny
|| fabs(eibasis(e,at,el)) > tiny) {
for(int j=e+1; j< nelectrons; j++) {
int s=(j < nspin_up) != (e < nspin_up);
int index=linear_parms(s)(p,i);
doublevar vkl=(//eibasis(e,at,k)*eibasis(j,at,el)
+eibasis(j,at,k)*eibasis(e,at,el));
deriv.gradient(index)+=vkl*eebasis(e,j,m);
}
}
}
}
}
}
int BCS_wf::getParmDeriv(Wavefunction_data *wfdata , Sample_point * sample,
Parm_deriv_return & parm_derivatives ) {
// analytic expressions below are valid only if jastrow can provide
// analytic derivatives (not sure if it is enough to test this)
if ( !parent->jastdata.supports(parameter_derivatives) ) return 0;
//cout << "BCS_wf: doing analytic derivatives with respect to parameters."
// << endl ;
int nparms_full=parent->nparms();
int nparms_start=parm_derivatives.nparms_start;
int nparms_end=parm_derivatives.nparms_end;
int nparms=nparms_end-nparms_start;
parm_derivatives.gradient.Resize(nparms);
parm_derivatives.hessian.Resize(nparms, nparms);
// gradients of the two-body orbital
Array3 <doublevar> twobody_parm_deriv;
jast.updateLap(&parent->jastdata,sample);
jast.get_twobody_ParmDeriv(sample,twobody_parm_deriv);
// gradient
parm_derivatives.gradient=0.0;
for(int det=0; det < ndet; det++) {
for (int alpha=0; alpha<nparms; alpha++) {
for(int i=0; i< nelectrons(0); i++) {
for (int j=0; j< nelectrons(1); j++) {
parm_derivatives.gradient(alpha)+=
twobody_parm_deriv(i,nelectrons(0)+j,alpha)*inverse(det)(i,j)*
parent->magnification_factor;
}
}
}
}
// hessian
parm_derivatives.hessian=0.0;
for(int det=0; det < ndet; det++) {
for (int alpha=0; alpha<nparms; alpha++) {
for (int beta=0; beta<nparms; beta++) {
parm_derivatives.hessian(alpha,beta)+=
parm_derivatives.gradient(alpha)*parm_derivatives.gradient(beta);
for(int i=0; i< nelectrons(0); i++) {
for (int j=0; j< nelectrons(1); j++) {
for(int k=0; k< nelectrons(0); k++) {
for (int l=0; l< nelectrons(1); l++) {
parm_derivatives.hessian(alpha,beta)-=
twobody_parm_deriv(i,nelectrons(0)+j,alpha)*inverse(det)(k,j)*
twobody_parm_deriv(k,nelectrons(0)+l,beta)*inverse(det)(i,l)*
parent->magnification_factor*parent->magnification_factor;
}
}
}
}
}
}
}
return 1;
}
