ldpc_1.cpp

关于Q元LDPC码的C++仿真程序

#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <iostream.h>
#include <fstream.h>
#include "LDPC_1.h"
#include "LDPC_2.h"
#include "Utils_1.h"
#include <ctype.h>
#include <wchar.h>


/**************************************************************
 *
 * LDPC Constructors
 * 
 **************************************************************/

void LDPC_Code::GetFromFile( ifstream &file )
{ 
  char dummy_buffer[10000];
  int rhos_index, lambdas_index;

  rhos_index = lambdas_index = 0;
  BOOLEAN GotMapInUse = FALSE;

  //----------------------------------------------
  // Go over file
  //----------------------------------------------
  while (!file.eof())
    {
      switch (file.peek()) 
      {
      case 'r':
         if (rhos_index >= MAX_RHOS)
         {
            cout << "LDPC_Code::GetFromFile: MAX_RHOS exceeded\n";
            exit(1);
         }

	 file >> rho_degs[rhos_index] >> rho_wts[rhos_index];
	 file.getline(dummy_buffer, sizeof(dummy_buffer));  // reach eol
         rhos_index++;
         break;
      case 'l':
         if (lambdas_index >= MAX_LAMBDAS)
         {
            cout << "LDPC_Code::GetFromFile: MAX_LAMBDAS exceeded\n";
            exit(1);
         }

	 file >> lambda_degs[lambdas_index] >> lambda_wts[lambdas_index];

         lambdas_index++;
	 file.getline(dummy_buffer, sizeof(dummy_buffer));  // reach eol
         break;
      case 'm':
		 GotMapInUse = TRUE;
         MapInUse.GetFromFile( file );

         // Initialize GF(q)
         GFq::Initialize(MapInUse.GetQ());
         break;
      default:
	 file.getline(dummy_buffer, sizeof(dummy_buffer));   // Skip line
      }
    }

  if (!GotMapInUse)
  {
	  cout << "mapping not defined\n";
	  exit(1);

  }
  rho_degs[rhos_index] = -1;
  rho_wts[rhos_index] = -1;
  lambda_degs[lambdas_index] = -1;
  lambda_wts[lambdas_index] = -1;
}



LDPC_Code::LDPC_Code( 
	      ifstream &File, 
	      int p_BlockLength,
	      channel *p_Channel )
  : BlockLength(p_BlockLength),
    Channel(p_Channel)
{
  GetFromFile( File );
}



/*************************************************************************
 *
 *  Calc rate
 *
 *************************************************************************/

double LDPC_Code::sigma_lambda()
{
  double n;

  n = 0;
  
  for (int i = 0; lambda_degs[i] != -1; i++)
    n += lambda_wts[i]/lambda_degs[i];
 
  return n;
}



double LDPC_Code::sigma_rho()
{
  double m;

  m = 0;
 
 for (int i = 0; rho_degs[i] != -1; i++)
   m += rho_wts[i]/rho_degs[i];

  return m;
}



double LDPC_Code::Calc_Symbol_Rate()
{
   double SigmaLambda = sigma_lambda();
   double SigmaRho = sigma_rho();

   return 1 - SigmaRho/SigmaLambda;
}






/**************************************************************
 *
 * mapping read from file
 * 
 **************************************************************/


void mapping::GetFromFile( ifstream &file )
// Read the mapping from the current position in the file
{ 
  file >> q;
  
  if (q > MAX_Q)
  {
     cout << "q exceeds MAX_Q in mapping:GetFromFile\n";
     exit(1);
  }

  for (int i = 0; i < q; i++)
  {
     file >> vals[i];
  }
}