Commit d73bb388 authored by Michael Tesch's avatar Michael Tesch
Browse files

of course windows doesnt have normal POSIX stuff like signgam.

parent 8c61a70b

duals/dual

+10 −0
Original line number Diff line number Diff line
@@ -31,6 +31,12 @@ 
#endif

#endif



/// Configure whether system has POSIX extern int signgam;

#ifndef CPPDUALS_HAVE_SIGNGAM

#ifndef _WIN32

#define CPPDUALS_HAVE_SIGNGAM 1

#endif

#endif

namespace duals {



/**
@@ -1020,11 +1026,15 @@ template<class T> dual<T> lgamma(const dual<T> & x) { 
  if (x.dpart() == T(0))

    return v;

  else {

#if CPPDUALS_HAVE_SIGNGAM

    int signgam_saved = signgam;

#endif

    int errno_saved = errno;

    T h(T(1) / (1ull << (std::numeric_limits<T>::digits / 3)));

    T w((lgamma(x.rpart()+h) - lgamma(x.rpart()-h))/(2*h));

#if CPPDUALS_HAVE_SIGNGAM

    signgam = signgam_saved;

#endif

    errno = errno_saved;

    return dual<T>(v, x.dpart() * w);

  }