SPOInfo.h

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//////////////////////////////////////////////////////////////////////////////////////
// This file is distributed under the University of Illinois/NCSA Open Source License.
// See LICENSE file in top directory for details.
//
// Copyright (c) 2016 Jeongnim Kim and QMCPACK developers.
//
// File developed by: Jaron T. Krogel, krogeljt@ornl.gov, Oak Ridge National Laboratory
//                    Mark A. Berrill, berrillma@ornl.gov, Oak Ridge National Laboratory
//
// File created by: Jaron T. Krogel, krogeljt@ornl.gov, Oak Ridge National Laboratory
//////////////////////////////////////////////////////////////////////////////////////


#ifndef QMCPLUSPLUS_SPO_INFO_H
#define QMCPLUSPLUS_SPO_INFO_H

#include <Configuration.h>

namespace qmcplusplus
{
/** base class to describe a single orbital in an SPOSet
   */
struct SPOInfo
{
  using RealType = QMCTraits::RealType;

  enum
  {
    DIM = OHMMS_DIM
  };

  static const int no_index;
  static const int no_degeneracy;
  static const RealType no_energy;

  /// original orbital index in the maximal basis
  int index;

  /// energetic degeneracy of the orbital
  int degeneracy;

  /// energy of the orbital (in Hartree units)
  RealType energy;

  SPOInfo();

  SPOInfo(int orb_index, RealType en = no_energy);

  virtual ~SPOInfo() {}


  inline bool has_index() const { return index != no_index; }

  inline bool has_energy() const { return energy != no_energy; }

  inline bool has_degeneracy() const { return degeneracy != no_degeneracy; }

  inline SPOInfo* copy() { return new SPOInfo(*this); }

  /// write orbital info to stdout
  void report(const std::string& pad = "") const;
};


namespace spoinfo
{
/// enumeration of possible orbital info orderings
enum orderings
{
  index_ordered = 0,
  energy_ordered,
  energy_and_index_ordered,
  unordered,
  no_order
};

/// comparison function for sorting SPOInfo based on orbital index
inline bool index_order(const SPOInfo* left, const SPOInfo* right) { return left->index < right->index; }

/// comparison functor for sorting SPOInfo based on energy
struct EnergyOrder
{
  using RealType = QMCTraits::RealType;
  RealType energy_tol;
  EnergyOrder(RealType tol = 1e-6) : energy_tol(tol){};
  ~EnergyOrder(){};
  inline bool operator()(const SPOInfo* left, const SPOInfo* right)
  {
    if (std::abs(left->energy - right->energy) < energy_tol)
      return index_order(left, right);
    else
      return left->energy < right->energy;
  }
};
} // namespace spoinfo


} // namespace qmcplusplus

#endif