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https://github.com/saitohirga/WSJT-X.git
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71 lines
2.1 KiB
C++
71 lines
2.1 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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#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_1
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#include <boost/math/special_functions/gamma.hpp>
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using boost::math::tgamma;
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// Define the policy to use:
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using namespace boost::math::policies; // may be convenient, or
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using boost::math::policies::policy;
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// Types of error whose action can be altered by policies:.
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using boost::math::policies::evaluation_error;
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using boost::math::policies::domain_error;
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using boost::math::policies::overflow_error;
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using boost::math::policies::domain_error;
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using boost::math::policies::pole_error;
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// Actions on error (in enum error_policy_type):
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using boost::math::policies::errno_on_error;
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using boost::math::policies::ignore_error;
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using boost::math::policies::throw_on_error;
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using boost::math::policies::user_error;
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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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//
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// Now use the policy when calling tgamma:
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// http://msdn.microsoft.com/en-us/library/t3ayayh1.aspx
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// Microsoft errno declared in STDLIB.H as "extern int errno;"
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int main()
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{
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errno = 0; // Reset.
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cout << "Result of tgamma(30000) is: "
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<< tgamma(30000, c_policy()) << endl; // Too big parameter
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cout << "errno = " << errno << endl; // errno 34 Numerical result out of range.
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cout << "Result of tgamma(-10) is: "
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<< boost::math::tgamma(-10, c_policy()) << endl; // Negative parameter.
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cout << "errno = " << errno << endl; // error 33 Numerical argument out of domain.
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} // int main()
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//]
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/* Output
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policy_eg_1.cpp
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Generating code
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Finished generating code
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policy_eg_1.vcxproj -> J:\Cpp\MathToolkit\test\Math_test\Release\policy_eg_1.exe
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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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