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67 lines
1.7 KiB
C++
67 lines
1.7 KiB
C++
// Copyright John Maddock 2007.
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// Copyright Paul A. Bristow 2010
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// Use, modification and distribution are subject to the
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// Boost Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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// Note that this file contains quickbook mark-up as well as code
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// and comments, don't change any of the special comment mark-ups!
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#include <iostream>
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using std::cout; using std::endl;
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#include <cerrno> // for ::errno
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//[policy_eg_5
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#include <boost/math/special_functions.hpp>
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// using boost::math::tgamma; // Would create an ambiguity between
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// 'double boost::math::tgamma<int>(T)' and
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// 'double 'anonymous-namespace'::tgamma<int>(RT)'.
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namespace mymath
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{ // unnamed
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using namespace boost::math::policies;
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typedef policy<
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domain_error<errno_on_error>,
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pole_error<errno_on_error>,
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overflow_error<errno_on_error>,
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evaluation_error<errno_on_error>
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> c_policy;
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BOOST_MATH_DECLARE_SPECIAL_FUNCTIONS(c_policy)
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/*`
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So that when we call `mymath::tgamma(z)`, we really end up calling
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`boost::math::tgamma(z, anonymous-namespace::c_policy())`.
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*/
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} // close unnamed namespace
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int main()
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{
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errno = 0;
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cout << "Result of tgamma(30000) is: "
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<< mymath::tgamma(30000) << endl;
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// tgamma in unnamed namespace in this translation unit (file) only.
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cout << "errno = " << errno << endl;
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cout << "Result of tgamma(-10) is: "
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<< mymath::tgamma(-10) << endl;
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cout << "errno = " << errno << endl;
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// Default tgamma policy would throw an exception, and abort.
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}
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//] //[/policy_eg_5]
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/*
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Output:
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Result of tgamma(30000) is: 1.#INF
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errno = 34
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Result of tgamma(-10) is: 1.#QNAN
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errno = 33
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*/
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