dpois.cpp

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#include "statsLib.h"

dvariable dpois(const double& k, const prevariable& lambda)
{
  RETURN_ARRAYS_INCREMENT();
  dvariable tmp = -k*log(lambda)+lambda + gammln(k+1.);
  RETURN_ARRAYS_DECREMENT();
  return tmp;
}

dvariable dpois(const prevariable& k, const prevariable& lambda)
{
  RETURN_ARRAYS_INCREMENT();
  dvariable tmp = -k*log(lambda)+lambda + gammln(k+1.);
  RETURN_ARRAYS_DECREMENT();
  return tmp;
}

dvariable dpois(const dvector& k, const dvar_vector& lambda)
{
  RETURN_ARRAYS_INCREMENT();
  int i;
  int n = size_count(k);
  dvariable nll=0;
  for(i = 1; i <= n; i++)
  {
    // nll -= k(i)*log(lambda(i))+lambda(i)+gammln(k(i)+1.);
    nll += -k(i)*log(lambda(i))+lambda(i)+gammln(k(i)+1.);
  }
  RETURN_ARRAYS_DECREMENT();
  return nll;
}