tactic.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/>.
 *
 */
 
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <smart_ptr.h>
 
#ifndef _libint2_src_bin_libint_tactic_h_
#define _libint2_src_bin_libint_tactic_h_
 
namespace libint2 {
 
  class DirectedGraph;
  class RecurrenceRelation;
 
  class DummyRandomizePolicy;
  class StdRandomizePolicy;
 
  class Tactic {
    public:
    typedef SafePtr<RecurrenceRelation> RR;
    typedef std::vector<RR> rr_stack;
 
    Tactic() {}
    virtual ~Tactic() {}
 
    virtual RR optimal_rr(const rr_stack& stack) const =0;
 
    // make return true if need to debug Tactic classes
    static constexpr bool class_debug() {
      return false;
    }
  };
 
  template <class RandomizePolicy = DummyRandomizePolicy>
    class FirstChoiceTactic : public Tactic {
    public:
    FirstChoiceTactic(const SafePtr<RandomizePolicy>& rpolicy = SafePtr<RandomizePolicy>(new RandomizePolicy)) : Tactic(), rpolicy_(rpolicy) {}
    virtual ~FirstChoiceTactic() {}
 
    RR optimal_rr(const rr_stack& stack) const {
      if (!stack.empty())
        return stack[0 + rpolicy_->noise(stack.size())];
      else
        return RR();
    }
 
    private:
    SafePtr<RandomizePolicy> rpolicy_;
  };
 
  class FewestNewVerticesTactic : public Tactic {
    public:
    FewestNewVerticesTactic(const SafePtr<DirectedGraph>& dg) : Tactic(), dg_(dg) {}
    virtual ~FewestNewVerticesTactic() {}
 
    RR optimal_rr(const rr_stack& stack) const;
 
    private:
    SafePtr<DirectedGraph> dg_;
  };
 
  class ZeroNewVerticesTactic : public Tactic {
    public:
    ZeroNewVerticesTactic(const SafePtr<DirectedGraph>& dg) : Tactic(), dg_(dg) {}
    virtual ~ZeroNewVerticesTactic() {}
 
    RR optimal_rr(const rr_stack& stack) const;
 
    private:
    SafePtr<DirectedGraph> dg_;
  };
 
  class RandomChoiceTactic : public Tactic {
    public:
    RandomChoiceTactic();
    virtual ~RandomChoiceTactic() {}
 
    RR optimal_rr(const rr_stack& stack) const;
  };
 
  class NullTactic : public Tactic {
    public:
    NullTactic() : Tactic() {}
    virtual ~NullTactic() {}
 
    RR optimal_rr(const rr_stack& stack) const;
  };
 
  class ParticleDirectionTactic : public Tactic {
    public:
      ParticleDirectionTactic(bool increase) : Tactic(), increase_(increase) {}
      virtual ~ParticleDirectionTactic() {}
 
      RR optimal_rr(const rr_stack& stack) const;
    private:
      bool increase_;
  };
 
  class TwoCenter_OS_Tactic : public Tactic {
    public:
    TwoCenter_OS_Tactic(unsigned lbra0,
                        unsigned lket0) : Tactic(), lbra0_(lbra0), lket0_(lket0) {}
      virtual ~TwoCenter_OS_Tactic() {}
 
      RR optimal_rr(const rr_stack& stack) const;
    private:
      unsigned lbra0_;
      unsigned lket0_;
  };
 
  class FourCenter_OS_Tactic : public Tactic {
    public:
      FourCenter_OS_Tactic(unsigned lbra0,
                           unsigned lket0,
                           unsigned lbra1,
                           unsigned lket1) : Tactic(), lbra0_(lbra0), lket0_(lket0),
                           lbra1_(lbra1), lket1_(lket1) {}
      virtual ~FourCenter_OS_Tactic() {}
 
      RR optimal_rr(const rr_stack& stack) const;
    private:
      unsigned lbra0_;
      unsigned lket0_;
      unsigned lbra1_;
      unsigned lket1_;
  };
 
 
  struct DummyRandomizePolicy {
    unsigned int noise(unsigned int nrrs) const { return 0; }
  };
 
  class StdRandomizePolicy {
    public:
    StdRandomizePolicy(double scale) : scale_(scale) {
      // Initialize state randomly
      time_t t;
      srandom(time(&t));
    }
 
    unsigned int noise(unsigned int nrrs) const {
      unsigned long rand = random();
      const unsigned long range = RAND_MAX;
      const unsigned int result = static_cast<unsigned int>(std::floor(nrrs*scale_*rand/range));
      return result;
    }
 
    private:
    double scale_;
  };
 
 
};
 
#endif