/*
 * @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
 */

#include "psi4/libqt/qt.h"
#include "defines.h"
#include "dfocc.h"

using namespace psi;

namespace psi {
namespace dfoccwave {

void DFOCC::ccsd_F_intr_low() {
    // defs
    SharedTensor2d K, T, U, Tau;

    // OO block
    // F_mi =  \sum_{Q} t_Q b_mi^Q
    K = SharedTensor2d(new Tensor2d("DF_BASIS_CC B (Q|IJ)", nQ, naoccA, naoccA));
    K->read(psio_, PSIF_DFOCC_INTS);
    FijA->gemv(true, K, T1c, 1.0, 0.0);
    K.reset();

    // F_mi +=  \sum_{Q,e} Tau"_ie^Q b_me^Q
    K = SharedTensor2d(new Tensor2d("DF_BASIS_CC B (Q|IA)", nQ, naoccA, navirA));
    K->read(psio_, PSIF_DFOCC_INTS);
    Tau = SharedTensor2d(new Tensor2d("Tau2pp (Q|IA)", nQ, naoccA, navirA));
    Tau->read(psio_, PSIF_DFOCC_AMPS);
    FijA->contract332(false, true, navirA, K, Tau, 1.0, 1.0);
    K.reset();
    Tau.reset();
    // FijA->print();

    // VV block
    // F_ae =  \sum_{Q} t_Q b_ae^Q
    K = SharedTensor2d(new Tensor2d("DF_BASIS_CC B (Q|AB)", nQ, navirA, navirA));
    K->read(psio_, PSIF_DFOCC_INTS, true, true);
    FabA->gemv(true, K, T1c, 1.0, 0.0);
    K.reset();

    // F_ae -=  \sum_{Q,m} Tau'_ma^Q b_me^Q
    K = SharedTensor2d(new Tensor2d("DF_BASIS_CC B (Q|IA)", nQ, naoccA, navirA));
    K->read(psio_, PSIF_DFOCC_INTS);
    Tau = SharedTensor2d(new Tensor2d("Tau2p (Q|IA)", nQ, naoccA, navirA));
    Tau->read(psio_, PSIF_DFOCC_AMPS);
    FabA->contract(true, false, navirA, navirA, nQ * naoccA, Tau, K, -1.0, 1.0);
    K.reset();
    Tau.reset();
    // FabA->print();

    // OV block
    // F_me +=  \sum_{Q} t_Q b_me^Q
    K = SharedTensor2d(new Tensor2d("DF_BASIS_CC B (Q|IA)", nQ, naoccA, navirA));
    K->read(psio_, PSIF_DFOCC_INTS);
    FiaA->gemv(true, K, T1c, 1.0, 0.0);

    // F_me -=  \sum_{Q,n} T_nm^Q b_ne^Q
    T = SharedTensor2d(new Tensor2d("T1 (Q|IJ)", nQ, naoccA, naoccA));
    T->read(psio_, PSIF_DFOCC_AMPS);
    FiaA->contract(true, false, naoccA, navirA, nQ * naoccA, T, K, -1.0, 1.0);
    K.reset();
    T.reset();
    // FiaA->print();

    // Ft_mi = F_mi + 1/2 \sum_{e} t_i^e F_me
    FtijA->gemm(false, true, FiaA, t1A, 0.5, 0.0);
    FtijA->add(FijA);
    // FtijA->print();

    // Ft_ae = F_ae - 1/2 \sum_{m} t_m^a F_me
    FtabA->gemm(true, false, t1A, FiaA, -0.5, 0.0);
    FtabA->add(FabA);
    // FtabA->print();

    // outfile->Printf("\tF int done.\n");

}  // end ccsd_F_intr_low
}  // namespace dfoccwave
}  // namespace psi
