/**********************************************************

This software is part of J.-S. Caux's ABACUS library.

Copyright (c).

-----------------------------------------------------------

File:  JSC_NRG.h

Purpose:  Declares NRG-related classes and functions.

***********************************************************/

#ifndef _NRG_
#define _NRG_

#include "JSC.h"

namespace JSC {

  DP K_Weight_integrand (Vect_DP args);  // weighing function for state selection

  //void Select_States_for_NRG (DP c_int, DP L, int N, int iKmin, int iKmax, int Nstates_required, bool symmetric_states, int iKmod,
  //		      int weighing_option, DP (*weight_integrand_fn) (Vect_DP), Vect_DP& args_to_weight_integrand);
  void Select_States_for_NRG (DP c_int, DP L, int N, int iKmin, int iKmax, int Nstates_required, bool symmetric_states, int iKmod,
			      //int weighing_option, DP (*weight_integrand_fn) (Vect_DP), Vect_DP& args_to_weight_integrand)
			      int weighing_option, Vect<complex <DP> >& FT_of_potential);
  
  void Build_DFF_Matrix_Block_for_NRG (DP c_int, DP L, int N, int iKmin, int iKmax, int Nstates_required, bool symmetric_states, int iKmod, 
				       int weighing_option, int label_left_begin, int label_left_end, int label_right_begin, int label_right_end,
				       int block_option, DP* DFF_block_1, DP* DFF_block_2, Vect_DP Kweight);

}

#endif // _NRG_