/*
 * @BEGIN LICENSE
 *
 * Psi4: an open-source quantum chemistry software package
 *
 * Copyright (c) 2007-2019 The Psi4 Developers.
 *
 * The copyrights for code used from other parties are included in
 * the corresponding files.
 *
 * This file is part of Psi4.
 *
 * Psi4 is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, version 3.
 *
 * Psi4 is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along
 * with Psi4; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * @END LICENSE
 */

/*! \file
    \ingroup DPD
    \brief Enter brief description of file here
*/

/* T3_RHF_ic(): Computes all T3(IJK,ABC) amplitudes for a given I, J,
** K combination for input T2, F, and E intermediates.  This function
** is specifically for AAB spin cases with RHF orbitals.
**  This _ic version assumes WAbEi is available in memory
** Arguments:
**
**   double ***W1: The target triples amplitudes in an nirreps x AB x
**   C array.  The memory for this must be allocated externally.
**
**   int nirreps: Number of irreps.
**
**   int I: Absolute index of orbital I.
**
**   int Gi: Irrep of I.
**
**   int J: Absolute index of orbital J.
**
**   int Gj: Irrep of J.
**
**   int K: Absolute index of orbital K.
**
**   int Gk: Irrep of K.
**
**   dpdbuf4 *T2: Pointer to dpd buffer for double excitation amps,
**   ordered (IJ,AB).
**
**   dpdbuf4 *F: Pointer to dpd buffer for three-virtual-index
**   intermediate, ordered (IA,BC).
**
**   dpdbuf4 *E: Pointer to dpd buffer for three-occupied-index
**   intermediate, ordered (IJ,KA).
**
**   dpdfile2 *fIJ: Pointer to the dpd file2 for the occ-occ block of
**   the Fock matrix (or other appropriate one-electron operator).
**
**   dpdfile2 *fAB: Pointer to the dpd file2 for the vir-vir block of
**   the Fock matrix (or other appropriate one-electron operator).
**
**   int *occpi: Number of occupied orbitals per irrep lookup array.
**
**   int *occ_off: Offset lookup for translating between absolute and
**   relative orbital indices for occupied space.
**
**   int *virtpi: Number of virtual orbitals per irrep lookup array.
**
**   int *vir_off: Offset lookup for translating between absolute and
**   relative orbital indices for virtual space.
**
**   double omega: constant to add to denominators - needed for EOM CC3
**
** TDC, July 2004
** -modified for RHF, RAK 2004
** -omega argument added, RAK 2006
*/

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include "psi4/libqt/qt.h"
#include "psi4/libdpd/dpd.h"
#include "psi4/psifiles.h"

namespace psi {

void DPD::T3_RHF_ic(double ***W1, int nirreps, int I, int Gi, int J, int Gj, int K, int Gk, dpdbuf4 *T2, dpdbuf4 *F,
                    dpdbuf4 *E, dpdfile2 *fIJ, dpdfile2 *fAB, int *occpi, int *occ_off, int *virtpi, int *vir_off,
                    double omega) {
    int h;
    int i, j, k;
    int ij, ji, ik, ki, jk, kj;
    int Gij, Gji, Gik, Gki, Gjk, Gkj, Gijk;
    int Ga, Gb, Gc;
    int Gd, Gl;
    int Gid, Gjd, Gkd;
    int Gab, Gcb, Gca;
    int Gla, Glb, Glc;
    int Gil, Gjl, Gkl;
    int a, b, c, A, B, C;
    int ab;
    int cd, bd, ad, dc;
    int id, jd, kd;
    int la, lb, lc;
    int il, jl, kl;
    int nrows, ncols, nlinks;
    double dijk, denom;
    double ***W2;
    int GE, GF, GC, GX3;

    GC = T2->file.my_irrep;
    /* F and E are assumed to have same irrep */
    GF = GE = F->file.my_irrep;
    GX3 = GC ^ GF;

    i = I - occ_off[Gi];
    j = J - occ_off[Gj];
    k = K - occ_off[Gk];

    Gij = Gji = Gi ^ Gj;
    Gik = Gki = Gi ^ Gk;
    Gjk = Gkj = Gj ^ Gk;
    Gijk = Gi ^ Gj ^ Gk;

    ij = T2->params->rowidx[I][J];
    ji = T2->params->rowidx[J][I];
    jk = T2->params->rowidx[J][K];
    kj = T2->params->rowidx[K][J];
    ik = T2->params->rowidx[I][K];
    ki = T2->params->rowidx[K][I];

    dijk = 0.0;
    if (fIJ->params->rowtot[Gi]) dijk += fIJ->matrix[Gi][i][i];
    if (fIJ->params->rowtot[Gj]) dijk += fIJ->matrix[Gj][j][j];
    if (fIJ->params->rowtot[Gk]) dijk += fIJ->matrix[Gk][k][k];

    W2 = (double ***)malloc(nirreps * sizeof(double **));

    for (Gab = 0; Gab < nirreps; Gab++) {
        Gc = Gab ^ Gijk ^ GX3;

        W2[Gab] = dpd_block_matrix(F->params->coltot[Gab], virtpi[Gc]);

        if (F->params->coltot[Gab] && virtpi[Gc]) {
            ::memset(W1[Gab][0], 0, F->params->coltot[Gab] * virtpi[Gc] * sizeof(double));
        }
    }

    /***** do terms that are (ab,c) and don't need sorted *****/
    for (Gd = 0; Gd < nirreps; Gd++) {
        /* term 1F */
        /* +t_JkDc * F_IDAB */
        Gid = Gi ^ Gd;
        Gab = Gid ^ GF;
        Gc = Gjk ^ Gd ^ GC;

        cd = T2->col_offset[Gjk][Gc];
        id = F->row_offset[Gid][I];

        nrows = F->params->coltot[Gid ^ GF];
        ncols = virtpi[Gc];
        nlinks = virtpi[Gd];

        if (nrows && ncols && nlinks)
            C_DGEMM('t', 't', nrows, ncols, nlinks, 1.0, F->matrix[Gid][id], nrows, &(T2->matrix[Gjk][kj][cd]), nlinks,
                    1.0, W1[Gab][0], ncols);
    }

    for (Gl = 0; Gl < nirreps; Gl++) {
        /* term 1E */
        /* -t_ILAB * E_JkLc */
        Gil = Gi ^ Gl;
        Gab = Gil ^ GC;
        Gc = Gjk ^ Gl ^ GE;

        lc = E->col_offset[Gjk][Gl];
        il = T2->row_offset[Gil][I];

        nrows = T2->params->coltot[Gil ^ GC];
        ncols = virtpi[Gc];
        nlinks = occpi[Gl];

        if (nrows && ncols && nlinks)
            C_DGEMM('t', 'n', nrows, ncols, nlinks, -1.0, T2->matrix[Gil][il], nrows, &(E->matrix[Gjk][jk][lc]), ncols,
                    1.0, W1[Gab][0], ncols);
    }

    /***** Do terms (ba,c) that need bac sorts *****/

    /* zero out W2 memory */
    for (Gab = 0; Gab < nirreps; Gab++) {
        Gc = Gab ^ Gijk ^ GX3;
        if (F->params->coltot[Gab] && virtpi[Gc]) {
            ::memset(W2[Gab][0], 0, F->params->coltot[Gab] * virtpi[Gc] * sizeof(double));
        }
    }

    for (Gd = 0; Gd < nirreps; Gd++) {
        /* term 6F */
        /* + F_JdBa * t_IkDc */
        Gjd = Gj ^ Gd;
        Gab = Gjd ^ GF;
        Gc = Gik ^ Gd ^ GC;

        cd = T2->col_offset[Gik][Gc];
        jd = F->row_offset[Gjd][J];

        nrows = F->params->coltot[Gjd ^ GF];
        ncols = virtpi[Gc];
        nlinks = virtpi[Gd];

        if (nrows && ncols && nlinks)
            C_DGEMM('t', 't', nrows, ncols, nlinks, 1.0, F->matrix[Gjd][jd], nrows, &(T2->matrix[Gik][ki][cd]), nlinks,
                    1.0, W2[Gab][0], ncols);
    }

    for (Gl = 0; Gl < nirreps; Gl++) {
        /* term 6E */
        /* +t_JlAb * E_IkLc */
        Gjl = Gj ^ Gl;
        Gab = Gjl ^ GC;
        Gc = Gik ^ Gl ^ GE;

        lc = E->col_offset[Gik][Gl];
        jl = T2->row_offset[Gjl][J];

        nrows = T2->params->coltot[Gjl ^ GC];
        ncols = virtpi[Gc];
        nlinks = occpi[Gl];

        if (nrows && ncols && nlinks)
            C_DGEMM('t', 'n', nrows, ncols, nlinks, -1.0, T2->matrix[Gjl][jl], nrows, &(E->matrix[Gik][ik][lc]), ncols,
                    1.0, W2[Gab][0], ncols);
    }

    sort_3d(W2, W1, nirreps, Gijk ^ GX3, F->params->coltot, F->params->colidx, F->params->colorb, F->params->rsym,
            F->params->ssym, vir_off, vir_off, virtpi, vir_off, F->params->colidx, bac, 1);

    /***** do (ac,b) terms that require acb sort *****/

    /* zero out W2 memory */
    for (Gab = 0; Gab < nirreps; Gab++) {
        Gc = Gab ^ Gijk ^ GX3;
        if (F->params->coltot[Gab] && virtpi[Gc]) {
            ::memset(W2[Gab][0], 0, F->params->coltot[Gab] * virtpi[Gc] * sizeof(double));
        }
    }

    for (Gd = 0; Gd < nirreps; Gd++) {
        /* term 2F */
        /* + F_IdAc * t_JkBd */
        Gid = Gi ^ Gd;
        Gca = Gid ^ GF;
        Gb = Gjk ^ Gd ^ GC;

        bd = T2->col_offset[Gjk][Gb];
        id = F->row_offset[Gid][I];

        nrows = F->params->coltot[Gid ^ GF];
        ncols = virtpi[Gb];
        nlinks = virtpi[Gd];

        if (nrows && ncols && nlinks)
            C_DGEMM('t', 't', nrows, ncols, nlinks, 1.0, F->matrix[Gid][id], nrows, &(T2->matrix[Gjk][jk][bd]), nlinks,
                    1.0, W2[Gca][0], ncols);
    }

    for (Gl = 0; Gl < nirreps; Gl++) {
        /* term 2E */
        /* -t_IlAc * E_KjLb */
        Gil = Gi ^ Gl;
        Gca = Gil ^ GC;
        Gb = Gjk ^ Gl ^ GE;

        lb = E->col_offset[Gjk][Gl];
        il = T2->row_offset[Gil][I];

        nrows = T2->params->coltot[Gil ^ GC];
        ncols = virtpi[Gb];
        nlinks = occpi[Gl];

        if (nrows && ncols && nlinks)
            C_DGEMM('t', 'n', nrows, ncols, nlinks, -1.0, T2->matrix[Gil][il], nrows, &(E->matrix[Gjk][kj][lb]), ncols,
                    1.0, W2[Gca][0], ncols);
    }

    sort_3d(W2, W1, nirreps, Gijk ^ GX3, F->params->coltot, F->params->colidx, F->params->colorb, F->params->rsym,
            F->params->ssym, vir_off, vir_off, virtpi, vir_off, F->params->colidx, acb, 1);

    /***** do (ca,b) terms that need a bca sort *****/

    /* zero out W2 memory */
    for (Gab = 0; Gab < nirreps; Gab++) {
        Gc = Gab ^ Gijk ^ GX3;
        if (F->params->coltot[Gab] && virtpi[Gc]) {
            ::memset(W2[Gab][0], 0, F->params->coltot[Gab] * virtpi[Gc] * sizeof(double));
        }
    }

    for (Gd = 0; Gd < nirreps; Gd++) {
        /* term 3F */
        /* + F_KdCa * t_JiBd */
        Gkd = Gk ^ Gd;
        Gca = Gkd ^ GF;
        Gb = Gij ^ Gd ^ GC;

        bd = T2->col_offset[Gij][Gb];
        kd = F->row_offset[Gkd][K];

        nrows = F->params->coltot[Gkd ^ GF];
        ncols = virtpi[Gb];
        nlinks = virtpi[Gd];

        if (nrows && ncols && nlinks)
            C_DGEMM('t', 't', nrows, ncols, nlinks, 1.0, F->matrix[Gkd][kd], nrows, &(T2->matrix[Gij][ji][bd]), nlinks,
                    1.0, W2[Gca][0], ncols);
    }

    for (Gl = 0; Gl < nirreps; Gl++) {
        /* term 3E */
        /* - t_KlCa * E_IjLb */
        Gkl = Gk ^ Gl;
        Gca = Gkl ^ GC;
        Gb = Gji ^ Gl ^ GE;

        lb = E->col_offset[Gji][Gl];
        kl = T2->row_offset[Gkl][K];

        nrows = T2->params->coltot[Gkl ^ GC];
        ncols = virtpi[Gb];
        nlinks = occpi[Gl];

        if (nrows && ncols && nlinks)
            C_DGEMM('t', 'n', nrows, ncols, nlinks, -1.0, T2->matrix[Gkl][kl], nrows, &(E->matrix[Gji][ij][lb]), ncols,
                    1.0, W2[Gca][0], ncols);
    }

    sort_3d(W2, W1, nirreps, Gijk ^ GX3, F->params->coltot, F->params->colidx, F->params->colorb, F->params->rsym,
            F->params->ssym, vir_off, vir_off, virtpi, vir_off, F->params->colidx, bca, 1);

    /***** do (cb,a) terms that require a cba sort *****/
    /* zero out W2 memory */
    for (Gab = 0; Gab < nirreps; Gab++) {
        Gc = Gab ^ Gijk ^ GX3;
        if (F->params->coltot[Gab] && virtpi[Gc]) {
            ::memset(W2[Gab][0], 0, F->params->coltot[Gab] * virtpi[Gc] * sizeof(double));
        }
    }

    for (Gd = 0; Gd < nirreps; Gd++) {
        /* term 4F */
        /* + F_KdCb * t_IjAd */
        Gkd = Gk ^ Gd;
        Gcb = Gkd ^ GF;
        Ga = Gij ^ Gd ^ GC;

        ad = T2->col_offset[Gij][Ga];
        kd = F->row_offset[Gkd][K];

        nrows = F->params->coltot[Gkd ^ GF];
        ncols = virtpi[Ga];
        nlinks = virtpi[Gd];

        if (nrows && ncols && nlinks)
            C_DGEMM('t', 't', nrows, ncols, nlinks, 1.0, F->matrix[Gkd][kd], nrows, &(T2->matrix[Gij][ij][ad]), nlinks,
                    1.0, W2[Gcb][0], ncols);
    }

    for (Gl = 0; Gl < nirreps; Gl++) {
        /* term 4E */
        /*  -t_KlCb * E_JiLa */
        Gkl = Gk ^ Gl;
        Gcb = Gkl ^ GC;
        Ga = Gji ^ Gl ^ GE;

        la = E->col_offset[Gji][Gl];
        kl = T2->row_offset[Gkl][K];

        nrows = T2->params->coltot[Gkl ^ GC];
        ncols = virtpi[Ga];
        nlinks = occpi[Gl];

        if (nrows && ncols && nlinks)
            C_DGEMM('t', 'n', nrows, ncols, nlinks, -1.0, T2->matrix[Gkl][kl], nrows, &(E->matrix[Gji][ji][la]), ncols,
                    1.0, W2[Gcb][0], ncols);
    }

    sort_3d(W2, W1, nirreps, Gijk ^ GX3, F->params->coltot, F->params->colidx, F->params->colorb, F->params->rsym,
            F->params->ssym, vir_off, vir_off, virtpi, vir_off, F->params->colidx, cba, 1);

    /***** do (bc,a) terms that require a cab sort *****/
    /* zero out W2 memory */
    for (Gab = 0; Gab < nirreps; Gab++) {
        Gc = Gab ^ Gijk ^ GX3;
        if (F->params->coltot[Gab] && virtpi[Gc]) {
            ::memset(W2[Gab][0], 0, F->params->coltot[Gab] * virtpi[Gc] * sizeof(double));
        }
    }

    for (Gd = 0; Gd < nirreps; Gd++) {
        /* term 5F */
        /* + t_IkAd * F_JdBc */
        Gjd = Gj ^ Gd;
        Gcb = Gjd ^ GF;
        Ga = Gik ^ Gd ^ GC;

        ad = T2->col_offset[Gik][Ga];
        jd = F->row_offset[Gjd][J];

        nrows = F->params->coltot[Gjd ^ GF];
        ncols = virtpi[Ga];
        nlinks = virtpi[Gd];

        if (nrows && ncols && nlinks)
            C_DGEMM('t', 't', nrows, ncols, nlinks, 1.0, F->matrix[Gjd][jd], nrows, &(T2->matrix[Gik][ik][ad]), nlinks,
                    1.0, W2[Gcb][0], ncols);
    }

    for (Gl = 0; Gl < nirreps; Gl++) {
        /* term 5E */
        /* - t_JlBc * E_Kila */
        Gjl = Gj ^ Gl;
        Gcb = Gjl ^ GC;
        Ga = Gik ^ Gl ^ GE;

        la = E->col_offset[Gik][Gl];
        jl = T2->row_offset[Gjl][J];

        nrows = T2->params->coltot[Gjl ^ GC];
        ncols = virtpi[Ga];
        nlinks = occpi[Gl];

        if (nrows && ncols && nlinks)
            C_DGEMM('t', 'n', nrows, ncols, nlinks, -1.0, T2->matrix[Gjl][jl], nrows, &(E->matrix[Gik][ki][la]), ncols,
                    1.0, W2[Gcb][0], ncols);
    }

    sort_3d(W2, W1, nirreps, Gijk ^ GX3, F->params->coltot, F->params->colidx, F->params->colorb, F->params->rsym,
            F->params->ssym, vir_off, vir_off, virtpi, vir_off, F->params->colidx, cab, 1);

    for (Gab = 0; Gab < nirreps; Gab++) {
        Gc = Gab ^ Gijk ^ GX3;

        for (ab = 0; ab < F->params->coltot[Gab]; ab++) {
            A = F->params->colorb[Gab][ab][0];
            B = F->params->colorb[Gab][ab][1];
            Ga = F->params->rsym[A];
            Gb = F->params->ssym[B];
            a = A - vir_off[Ga];
            b = B - vir_off[Gb];

            for (c = 0; c < virtpi[Gc]; c++) {
                C = vir_off[Gc] + c;

                denom = dijk;
                if (fAB->params->rowtot[Ga]) denom -= fAB->matrix[Ga][a][a];
                if (fAB->params->rowtot[Gb]) denom -= fAB->matrix[Gb][b][b];
                if (fAB->params->rowtot[Gc]) denom -= fAB->matrix[Gc][c][c];

                W1[Gab][ab][c] /= (denom + omega);

            } /* c */
        }     /* ab */
    }         /* Gab */

    for (Gab = 0; Gab < nirreps; Gab++) {
        Gc = Gab ^ Gijk ^ GX3;
        free_dpd_block(W2[Gab], F->params->coltot[Gab], virtpi[Gc]);
    }
    free(W2);
}

}  // namespace psi
