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			71 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
		
		
			
		
	
	
			71 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
|  | //  Copyright John Maddock 2007.
 | ||
|  | //  Copyright Paul A> Bristow 2010
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|  | //  Use, modification and distribution are subject to the
 | ||
|  | //  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; | ||
|  | #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; | ||
|  | 
 | ||
|  | // 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; | ||
|  | // Types of error whose action can be altered by policies:.
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|  | using boost::math::policies::evaluation_error; | ||
|  | using boost::math::policies::domain_error; | ||
|  | using boost::math::policies::overflow_error; | ||
|  | using boost::math::policies::domain_error; | ||
|  | using boost::math::policies::pole_error; | ||
|  | // Actions on error (in enum error_policy_type):
 | ||
|  | using boost::math::policies::errno_on_error; | ||
|  | using boost::math::policies::ignore_error; | ||
|  | using boost::math::policies::throw_on_error; | ||
|  | using boost::math::policies::user_error; | ||
|  | 
 | ||
|  | typedef policy< | ||
|  |    domain_error<errno_on_error>, | ||
|  |    pole_error<errno_on_error>, | ||
|  |    overflow_error<errno_on_error>, | ||
|  |    evaluation_error<errno_on_error>  | ||
|  | > c_policy; | ||
|  | //
 | ||
|  | // 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() | ||
|  | { | ||
|  |    errno = 0; // Reset.
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|  |    cout << "Result of tgamma(30000) is: "  | ||
|  |       << 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: "  | ||
|  |       << 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
 | ||
|  | 
 | ||
|  | policy_eg_1.cpp | ||
|  |   Generating code | ||
|  |   Finished generating code | ||
|  |   policy_eg_1.vcxproj -> J:\Cpp\MathToolkit\test\Math_test\Release\policy_eg_1.exe | ||
|  |   Result of tgamma(30000) is: 1.#INF | ||
|  |   errno = 34 | ||
|  |   Result of tgamma(-10) is: 1.#QNAN | ||
|  |   errno = 33 | ||
|  | 
 | ||
|  | */ | ||
|  | 
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|  | 
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