IncompleteGammaComplement Class Reference

#include <IncompleteGammaComplement.h>

Static Public Member Functions
static float	ln (float a, float x)
static float	value (float a, float x)

Detailed Description

Computes the complement Q(a,x)=1-P(a,x) of the incomplete gamma function. Computes its natural logarithm, useful for comparing very small values. source: Numerical Recipes

Definition at line 9 of file IncompleteGammaComplement.h.

Member Function Documentation

ln()

float IncompleteGammaComplement::ln ( float  a, float  x  )

static

Definition at line 22 of file IncompleteGammaComplement.cc.

References a, JetChargeProducer_cfi::exp, GammaContinuedFraction(), GammaLn(), GammaSeries(), CrabHelper::log, and x.

Referenced by LnChiSquaredProbability().

                                                    {
  if (x < 0.0 || a <= 0.0)
    edm::LogInfo("IncompleteGammaComplement") << "IncompleteGammaComplement::invalid arguments";
  if (x < (a + 1.0))
    // take the complement of the series representation
    return log(1. - GammaSeries(a, x) * (exp(-x + a * log(x) - GammaLn(a))));
  else
    // use the continued fraction representation
    return log(GammaContinuedFraction(a, x)) - x + a * log(x) - GammaLn(a);
}

value()

float IncompleteGammaComplement::value ( float  a, float  x  )

static

Definition at line 11 of file IncompleteGammaComplement.cc.

References a, JetChargeProducer_cfi::exp, GammaContinuedFraction(), GammaLn(), GammaSeries(), CrabHelper::log, and x.

Referenced by Types.int32::__nonzero__(), Types.uint32::__nonzero__(), Types.int64::__nonzero__(), Types.uint64::__nonzero__(), Types.double::__nonzero__(), Types.bool::__nonzero__(), Types.string::__nonzero__(), average.Average::average(), ChiSquaredProbability(), Types.string::configValue(), Types.FileInPath::configValue(), Mixins.UsingBlock::dumpPython(), Mixins.UsingBlock::insertInto(), Types.int32::insertInto(), Types.uint32::insertInto(), Types.int64::insertInto(), Types.uint64::insertInto(), Types.double::insertInto(), Types.bool::insertInto(), Types.string::insertInto(), Types.FileInPath::insertInto(), Types.vint32::insertInto(), Types.vuint32::insertInto(), Types.vint64::insertInto(), Types.vuint64::insertInto(), Types.vdouble::insertInto(), Types.vbool::insertInto(), and Types.vstring::insertInto().

                                                       {
  if (x < 0.0 || a <= 0.0)
    edm::LogInfo("IncompleteGammaComplement") << "IncompleteGammaComplement::invalid arguments";
  if (x < (a + 1.0))
    // take the complement of the series representation
    return 1. - GammaSeries(a, x) * (exp(-x + a * log(x) - GammaLn(a)));
  else
    // use the continued fraction representation
    return GammaContinuedFraction(a, x) * (exp(-x + a * log(x) - GammaLn(a)));
}