LogNormal.cxx

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#ifdef HAVE_CONFIG_H
#include "config.h"
#else
#ifdef _MSC_VER
#include "msdevstudio/MSconfig.h"
#endif
#endif

#include "LogNormal.h"

#include "FunctionHelper.h"

#include <cmath>
#include <cassert>

using std::distance;

#ifdef ITERATOR_MEMBER_DEFECT
using namespace std;
#else
using std::exp;
using std::vector;
#endif

namespace {
  enum { norm = 0, mean = 1, sigma = 2, //< FWHM/2.36
         tail = 3 };
}

LogNormal::LogNormal ( )
{
  initialize ();
}

LogNormal::LogNormal ( double n, double m, double s, double t )
{
  initialize ();
  
  m_parms[norm] = n;
  m_parms[mean] = m;
  m_parms[sigma] = s;
  m_parms[tail] = t;
}

void LogNormal::initialize ()
{
  m_name = "LogNormal";

  m_parm_names.push_back ( "Norm" );
  m_parm_names.push_back ( "Mean" );
  m_parm_names.push_back ( "Sigma" );
  m_parm_names.push_back ( "Tail" );

  resize ();
}

FunctionBase * LogNormal::clone () const
{
  return new LogNormal ( *this );
}

double LogNormal::operator () ( double x ) const
{
//---- If tail is small then Gauss

  double  qa=0,qb=0,qc=0,qx=0,qy=0;
  double result=0;

  if(fabs(m_parms[3]) < 1.e-7)
    qc = 0.5*pow((( x -m_parms[1])/m_parms[2]),2);
  else {
    qa = m_parms[3]*sqrt(log(4.));
    qb = sinh(qa)/qa;
    qx = ( x - m_parms[1])/m_parms[2]*qb;
    qy = 1.+m_parms[3]*qx;

    //---- Cutting curve from right side

    if( qy > 1.E-7)
      qc = 0.5*(pow((log(qy)/m_parms[3]),2) + m_parms[3]*m_parms[3]);
    else
      qc = 15.;
  }
  //----

  result =  m_parms[0] * exp(-qc);

  return result;
}

void 
LogNormal::
initialParameters ( const FunctionHelper * helper )
{
  double min_x = helper->minCoord ();
  double max_x = helper->maxCoord ();
  int size = helper->size();
  double total = helper->getTotal ();

  m_parms[norm] = total * ( max_x - min_x ) / size;
  m_parms[mean] = helper->meanCoord ();
  m_parms[sigma] = helper->stdCoord ();
  m_parms[tail] = 0.;
}

double LogNormal::derivByParm ( int i, double x ) const
{
  assert ( false );
  return 0.;
}

bool
LogNormal::
hasDerivatives () const
{
  return false;
}

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