Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

This is the documentation for a snapshot of the develop branch, built from commit c52d382a21.
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cos_pi

#include <boost/math/special_functions/cos_pi.hpp>
namespace boost{ namespace math{

template <class T>
calculated-result-type cos_pi(T x);

template <class T, class Policy>
calculated-result-type cos_pi(T x, const Policy&);

}} // namespaces

Returns the cosine of π  x.

The return type of this function is computed using the result type calculation rules: the return is double when x is an integer type and T otherwise.

The final Policy argument is optional and can be used to control the behaviour of the function: how it handles errors, what level of precision to use etc. Refer to the policy documentation for more details.

This function performs exact all-integer arithmetic argument reduction before computing the cosine of π·x.

Table 8.80. Error rates for cos_pi

GNU C++ version 7.1.0
linux
double

GNU C++ version 7.1.0
linux
long double

Sun compiler version 0x5150
Sun Solaris
long double

Microsoft Visual C++ version 14.1
Win32
double

sin_pi and cos_pi

Max = 0ε (Mean = 0ε)

Max = 0.991ε (Mean = 0.302ε)

Max = 0.991ε (Mean = 0.302ε)

Max = 0.996ε (Mean = 0.284ε)

sin_pi and cos_pi near integers and half integers

Max = 0ε (Mean = 0ε)

Max = 0.976ε (Mean = 0.28ε)

Max = 0.976ε (Mean = 0.28ε)

Max = 0.996ε (Mean = 0.298ε)



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