Boost C++ Libraries: Ticket #12234: boost::multiprecision x64 win32 hard compile errors on windows with mpir

tlyons@… — Mon, 30 May 2016 13:31:31 GMT

I should have given the code example that triggered the problem. Uncomment the relevant part and it runs successfully:

#include "stdafx.h"
#include <boost/multiprecision/gmp.hpp>
#include <boost/math/special_functions/gamma.hpp>
#include "Safeint3.hpp" // for a safe fix: http://safeint.codeplex.com/
#include <iostream>
namespace boost {
	namespace multiprecision {
		template <unsigned Digits10>
		struct gmp_float;
		typedef number<gmp_float<100> >   mpf_float_100;
	}
} // namespaces
/*
// uncomment this block to fix the code
double __gmpf_get_d_2exp(long * p, mpf_srcptr a) {
	mpir_si temp{ *p };
	double b = __gmpf_get_d_2exp(&temp, a);
	*p = SafeInt<long>(temp);
	return b;
}
*/
using namespace boost::multiprecision;
int fourth() {
	mpf_float_100 b = 2;
	std::cout << std::numeric_limits<mpf_float_100>::digits << std::endl;
	// We can use any C++ std lib function:
	std::cout << log(b) << std::endl; // print log(2)// ERROR on this line
	// We can also use any function from Boost.Math:
	std::cout << boost::math::tgamma(b) << std::endl;
	// These even work when the argument is an expression template:
	std::cout << boost::math::tgamma(b * b) << std::endl;
	return 0;
}

John Maddock — Mon, 06 Jun 2016 17:56:55 GMT

I need to check with latest MPIR, but my version has no such type as mpir_si, further the function call that's causing the issue (mpf_get_d_2exp) is documented as:

double mpf_get_d_2exp (signed long int *exp, const mpf_t op)

In the latest GMP documentation. Is this an incompatibility between GMP and MPIR by any chance?

John Maddock — Tue, 07 Jun 2016 18:12:32 GMT

I believe this to be an MPIR bug: https://github.com/wbhart/mpir/commit/fb616eed78d0a32dc9e53b355b0c2d42c1209907#commitcomment-17775327

Will commit a workaround shortly.

status, milestone changed; resolution set

John Maddock — Tue, 07 Jun 2016 18:15:32 GMT

status new → closed
resolution → fixed
milestone To Be Determined → Boost 1.62.0

Workaround/fix in https://github.com/boostorg/multiprecision/commit/0b7591dd3a6425786bfdc58d481de7d796076a7c