Erf.cc

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// -*- C++ -*-
// $Id: Erf.cc,v 1.6 2010/06/16 18:22:01 garren Exp $
 
#include <cmath>
 
#include "CLHEP/GenericFunctions/Erf.hh"
#include "CLHEP/GenericFunctions/Gaussian.hh"
#include <assert.h>
namespace Genfun {
FUNCTION_OBJECT_IMP(Erf)
 
Erf::Erf()
{
  _incompleteGamma.a().setValue(0.5);
}
 
Erf::Erf(const Erf & right):
  AbsFunction(right), _incompleteGamma(right._incompleteGamma)
{
}
 
Erf::~Erf() {
}
 
double Erf::operator() (double x) const {
  return x<0 ? -_incompleteGamma(x*x): _incompleteGamma(x*x);
}
 
// don't generate warnings about unused parameter inside assert
#if defined __GNUC__ 
  #if __GNUC__ > 3 && __GNUC_MINOR__ > 6
    #pragma GCC diagnostic push
    #pragma GCC diagnostic ignored "-Wunused-parameter"
  #endif
#endif
#ifdef __clang__
  #pragma clang diagnostic push
  #pragma clang diagnostic ignored "-Wunused-parameter"
#endif
Derivative Erf::partial(unsigned int index) const {
  assert(index==0);
  Gaussian gauss = Gaussian();
  gauss.sigma().setValue(sqrt(2.0));
  const AbsFunction & fPrime = 2.0*gauss;
  return Derivative(& fPrime);
}
#if defined __GNUC__ 
  #if __GNUC__ > 3 && __GNUC_MINOR__ > 6
    #pragma GCC diagnostic pop
  #endif
#endif
#ifdef __clang__
  #pragma clang diagnostic pop
#endif
 
} // namespace Genfun