comp_11_tig12_11.h

/*
 *  Copyright (C) 2004-2021 Edward F. Valeev
 *
 *  This file is part of Libint.
 *
 *  Libint is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  Libint 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with Libint.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
 
#ifndef _libint2_src_bin_libint_cr11tig1211_h_
#define _libint2_src_bin_libint_cr11tig1211_h_
 
#include <generic_rr.h>
#include <tig12_11_11.h>
#include <gaussoper.h>
 
namespace libint2 {
 
  template <class BFSet>
    class CR_11_TiG12_11 : public GenericRecurrenceRelation< CR_11_TiG12_11<BFSet>,
                                                             BFSet,
                                                             GenIntegralSet_11_11<BFSet,TiG12,mType> >
    {
    public:
      typedef CR_11_TiG12_11 ThisType;
      typedef BFSet BasisFunctionType;
      typedef GenIntegralSet_11_11<BFSet,TiG12,mType> TargetType;
      typedef GenericRecurrenceRelation<ThisType,BFSet,TargetType> ParentType;
      friend class GenericRecurrenceRelation<ThisType,BFSet,TargetType>;
      static const unsigned int max_nchildren = 8;
 
      using ParentType::Instance;
 
      static bool directional() { return false; }
 
    private:
      using ParentType::RecurrenceRelation::expr_;
      using ParentType::RecurrenceRelation::nflops_;
      using ParentType::target_;
      using ParentType::is_simple;
      template<class RR, class C> friend class ChildFactory;
 
      CR_11_TiG12_11(const SafePtr<TargetType>&, unsigned int dir);
      static std::string descr() { return "CR"; }
 
    };
 
  template <class F>
    CR_11_TiG12_11<F>::CR_11_TiG12_11(const SafePtr<TargetType>& Tint,
                                      unsigned int dir) :
    ParentType(Tint,dir)
    {
      if (dir != 0)
        return;
      using namespace libint2::algebra;
      using namespace libint2::prefactor;
      using namespace libint2::braket;
      // kinetic energy of which electron?
      const int i = target_->oper()->descr().K();
      const R12kG12 G0(R12_k_G12_Descr(0));
      const R12kG12 G2(R12_k_G12_Descr(2));
 
      F a(Tint->bra(0,0));
      F b(Tint->ket(0,0));
      F c(Tint->bra(1,0));
      F d(Tint->ket(1,0));
 
      if (i == 0) {
        if (b.contracted() || target_->oper()->descr().contracted())
          return;
      }
      if (i == 1) {
        if (d.contracted() || target_->oper()->descr().contracted())
          return;
      }
 
      // [T1,G12]
      if (i == 0) {
        typedef GenIntegralSet_11_11<BasisFunctionType,R12kR12lG12,EmptySet> ChildType;
        ChildFactory<ThisType,ChildType> factory(this);
        for(int xyz=0; xyz<3; ++xyz) {
          R12k_R12l_G12_Descr descr(IntVec3(),unit_intvec3(xyz));
          factory.wedge(_pbra(a,c) , Nabla1(_pket(b,d),xyz), EmptySet(), R12kR12lG12(descr));
        }
        if (is_simple()) expr_ *= Scalar(2.0) * Scalar("gamma");
      }
      // [T2,G12]
      if (i == 1) {
        typedef GenIntegralSet_11_11<BasisFunctionType,R12kR12lG12,EmptySet> ChildType;
        ChildFactory<ThisType,ChildType> factory(this);
        for(int xyz=0; xyz<3; ++xyz) {
          R12k_R12l_G12_Descr descr(IntVec3(),unit_intvec3(xyz));
          factory.wedge(_pbra(a,c) , Nabla2(_pket(b,d),xyz), EmptySet(), R12kR12lG12(descr));
        }
        if (is_simple()) expr_ *= Scalar(-2.0) * Scalar("gamma");
      }
 
      {
        typedef GenIntegralSet_11_11<BasisFunctionType,R12kG12,mType> ChildType;
        ChildFactory<ThisType,ChildType> factory(this);
        auto ab_G0_cd = factory.make_child(a,b,c,d,0u,G0);
        if (is_simple())
          expr_ += Scalar(3.0) * Scalar("gamma") * ab_G0_cd;
 
        auto ab_G2_cd = factory.make_child(a,b,c,d,0u,G2);
        if (is_simple())
          expr_ += Scalar(-2.0) * Scalar("gamma") * Scalar("gamma") * ab_G2_cd;
      }
 
    }
 
};
 
#endif