#include "meam.h"
#include "math_special.h"

using namespace LAMMPS_NS;

void
MEAM::meam_dens_final(int nlocal, int eflag_either, int eflag_global, int eflag_atom, double* eng_vdwl,
                      double* eatom, int ntype, int* type, int* fmap, int& errorflag)
{
  int i, elti;
  int m;
  double rhob, G, dG, Gbar, dGbar, gam, shp[3], Z;
  double B, denom, rho_bkgd;

  //     Complete the calculation of density

  for (i = 0; i < nlocal; i++) {
    elti = fmap[type[i]];
    if (elti >= 0) {
      rho1[i] = 0.0;
      rho2[i] = -1.0 / 3.0 * arho2b[i] * arho2b[i];
      rho3[i] = 0.0;
      for (m = 0; m < 3; m++) {
        rho1[i] = rho1[i] + arho1[i][m] * arho1[i][m];
        rho3[i] = rho3[i] - 3.0 / 5.0 * arho3b[i][m] * arho3b[i][m];
      }
      for (m = 0; m < 6; m++) {
        rho2[i] = rho2[i] + this->v2D[m] * arho2[i][m] * arho2[i][m];
      }
      for (m = 0; m < 10; m++) {
        rho3[i] = rho3[i] + this->v3D[m] * arho3[i][m] * arho3[i][m];
      }

      if (rho0[i] > 0.0) {
        if (this->ialloy == 1) {
          t_ave[i][0] = t_ave[i][0] / tsq_ave[i][0];
          t_ave[i][1] = t_ave[i][1] / tsq_ave[i][1];
          t_ave[i][2] = t_ave[i][2] / tsq_ave[i][2];
        } else if (this->ialloy == 2) {
          t_ave[i][0] = this->t1_meam[elti];
          t_ave[i][1] = this->t2_meam[elti];
          t_ave[i][2] = this->t3_meam[elti];
        } else {
          t_ave[i][0] = t_ave[i][0] / rho0[i];
          t_ave[i][1] = t_ave[i][1] / rho0[i];
          t_ave[i][2] = t_ave[i][2] / rho0[i];
        }
      }

      gamma[i] = t_ave[i][0] * rho1[i] + t_ave[i][1] * rho2[i] + t_ave[i][2] * rho3[i];

      if (rho0[i] > 0.0) {
        gamma[i] = gamma[i] / (rho0[i] * rho0[i]);
      }

      Z = this->Z_meam[elti];

      G = G_gam(gamma[i], this->ibar_meam[elti], errorflag);
      if (errorflag != 0)
        return;
      get_shpfcn(this->lattce_meam[elti][elti], shp);
      if (this->ibar_meam[elti] <= 0) {
        Gbar = 1.0;
        dGbar = 0.0;
      } else {
        if (this->mix_ref_t == 1) {
          gam = (t_ave[i][0] * shp[0] + t_ave[i][1] * shp[1] + t_ave[i][2] * shp[2]) / (Z * Z);
        } else {
          gam = (this->t1_meam[elti] * shp[0] + this->t2_meam[elti] * shp[1] + this->t3_meam[elti] * shp[2]) /
                (Z * Z);
        }
        Gbar = G_gam(gam, this->ibar_meam[elti], errorflag);
      }
      rho[i] = rho0[i] * G;

      if (this->mix_ref_t == 1) {
        if (this->ibar_meam[elti] <= 0) {
          Gbar = 1.0;
          dGbar = 0.0;
        } else {
          gam = (t_ave[i][0] * shp[0] + t_ave[i][1] * shp[1] + t_ave[i][2] * shp[2]) / (Z * Z);
          Gbar = dG_gam(gam, this->ibar_meam[elti], dGbar);
        }
        rho_bkgd = this->rho0_meam[elti] * Z * Gbar;
      } else {
        if (this->bkgd_dyn == 1) {
          rho_bkgd = this->rho0_meam[elti] * Z;
        } else {
          rho_bkgd = this->rho_ref_meam[elti];
        }
      }
      rhob = rho[i] / rho_bkgd;
      denom = 1.0 / rho_bkgd;

      G = dG_gam(gamma[i], this->ibar_meam[elti], dG);

      dgamma1[i] = (G - 2 * dG * gamma[i]) * denom;

      if (!iszero(rho0[i])) {
        dgamma2[i] = (dG / rho0[i]) * denom;
      } else {
        dgamma2[i] = 0.0;
      }

      //     dgamma3 is nonzero only if we are using the "mixed" rule for
      //     computing t in the reference system (which is not correct, but
      //     included for backward compatibility
      if (this->mix_ref_t == 1) {
        dgamma3[i] = rho0[i] * G * dGbar / (Gbar * Z * Z) * denom;
      } else {
        dgamma3[i] = 0.0;
      }

      B = this->A_meam[elti] * this->Ec_meam[elti][elti];

      if (!iszero(rhob)) {
        if (this->emb_lin_neg == 1 && rhob <= 0) {
          frhop[i] = -B;
        } else {
          frhop[i] = B * (log(rhob) + 1.0);
        }
        if (eflag_either != 0) {
          if (eflag_global != 0) {
            if (this->emb_lin_neg == 1 && rhob <= 0) {
              *eng_vdwl = *eng_vdwl - B * rhob;
            } else {
              *eng_vdwl = *eng_vdwl + B * rhob * log(rhob);
            }
          }
          if (eflag_atom != 0) {
            if (this->emb_lin_neg == 1 && rhob <= 0) {
              eatom[i] = eatom[i] - B * rhob;
            } else {
              eatom[i] = eatom[i] + B * rhob * log(rhob);
            }
          }
        }
      } else {
        if (this->emb_lin_neg == 1) {
          frhop[i] = -B;
        } else {
          frhop[i] = B;
        }
      }
    }
  }
}

