Difference between revisions of "cpp/numeric/special functions/riemann zeta"
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[http://mathworld.wolfram.com/RiemannZetaFunction.html Weisstein, Eric W. "Riemann Zeta Function."] From MathWorld--A Wolfram Web Resource. | [http://mathworld.wolfram.com/RiemannZetaFunction.html Weisstein, Eric W. "Riemann Zeta Function."] From MathWorld--A Wolfram Web Resource. | ||
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Revision as of 07:22, 29 November 2019
Defined in header <cmath>
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double riemann_zeta( double arg ); float riemann_zeta( float arg ); |
(1) | (since C++17) |
double riemann_zeta( IntegralType arg ); |
(2) | (since C++17) |
Contents |
Parameters
arg | - | value of a floating-point or integral type |
Return value
If no errors occur, value of the Riemann zeta function of arg
, ζ(arg), defined for the entire real axis:
- For arg>1, Σ∞n=1n-arg
- For 0≤arg≤1,
Σ∞n=1(-1)n-1n-arg1 1-21-arg - For arg<0, 2argπarg-1sin(
)Γ(1−arg)ζ(1−arg)πarg 2
Error handling
Errors may be reported as specified in math_errhandling
- If the argument is NaN, NaN is returned and domain error is not reported
Notes
Implementations that do not support C++17, but support ISO 29124:2010, provide this function if __STDCPP_MATH_SPEC_FUNCS__
is defined by the implementation to a value at least 201003L and if the user defines __STDCPP_WANT_MATH_SPEC_FUNCS__
before including any standard library headers.
Implementations that do not support ISO 29124:2010 but support TR 19768:2007 (TR1), provide this function in the header tr1/cmath
and namespace std::tr1
.
An implementation of this function is also available in boost.math
Example
#include <cmath> #include <iostream> int main() { // spot checks for well-known values std::cout << "ζ(-1) = " << std::riemann_zeta(-1) << '\n' << "ζ(0) = " << std::riemann_zeta(0) << '\n' << "ζ(1) = " << std::riemann_zeta(1) << '\n' << "ζ(0.5) = " << std::riemann_zeta(0.5) << '\n' << "ζ(2) = " << std::riemann_zeta(2) << ' ' << "(π²/6 = " << std::pow(std::acos(-1),2)/6 << ")\n"; }
Output:
ζ(-1) = -0.0833333 ζ(0) = -0.5 ζ(1) = inf ζ(0.5) = -1.46035 ζ(2) = 1.64493 (π²/6 = 1.64493)
External links
Weisstein, Eric W. "Riemann Zeta Function." From MathWorld--A Wolfram Web Resource.