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// Copyright John Maddock 2007.
// Copyright Paul A. Bristow 2010
// Use, modification and distribution are subject to the
// Boost Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
// Note that this file contains quickbook mark-up as well as code
// and comments, don't change any of the special comment mark-ups!
// Define tgamma function with a no overflow policy
// into a specific namespace-scope.
#include <iostream>
using std::cout; using std::endl;
//[policy_ref_snip12
#include <boost/math/special_functions/gamma.hpp>
//using boost::math::tgamma;
// Need not declare using boost::math::tgamma here,
// because will define tgamma in myspace using macro below.
namespace myspace
{
using namespace boost::math::policies;
// Define a policy that does not throw on overflow:
typedef policy<overflow_error<errno_on_error> > my_policy;
// Define the special functions in this scope to use the policy:
BOOST_MATH_DECLARE_SPECIAL_FUNCTIONS(my_policy)
}
// Now we can use myspace::tgamma etc.
// They will automatically use "my_policy":
//
double t = myspace::tgamma(30.0); // Will *not* throw on overflow,
// despite the large value of factorial 30 = 265252859812191058636308480000000
// unlike default policy boost::math::tgamma;
//]
int main()
{
cout << "myspace::tgamma(30.0) = " << t << endl;
}
/*
Output:
myspace::tgamma(30.0) = 8.84176e+030
*/
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