std::comp_e...p_ellint_2l(3)

✨ NAME ✨

std::comp_ellint_2,std::comp_ellint_2f,std::comp_ellint_2l — std::comp_ellint_2,std::comp_ellint_2f,std::comp_ellint_2l

Okay bestie, welcome to the C++ Standard Libary manual’s page for the std::comp_ellint_2 trio 💖 — the page handle is std::comp_e...p_ellint_2l(3), and we’re about to get into some complete elliptic integral of the second kind energy. Slay.

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🦋 Synopsis 🦋

double      comp_ellint_2( double arg );

double      comp_ellint_2( float arg );
double      comp_ellint_2( long double arg );  (1)
float       comp_ellint_2f( float arg );

long double comp_ellint_2l( long double arg );
double      comp_ellint_2( IntegralType arg ); (2)

1. This one computes the complete elliptic integral of the second kind of arg, periodt.
2. This is a set of overloads or a function template accepting an argument of any integral type. It’s equivalent to (1) after casting the argument to double.

And listen, bestie — as with all special functions, comp_ellint_2 is only guaranteed to be available in <cmath> 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. Iyk what I mean 👑

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🍓 Parameters 🍓

• arg — value of a floating-point or integral type. That’s the whole vibe check for this parameter, no cap.

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🌈 Return value 🌈

If no errors occur, you get the value of the complete elliptic integral of the second kind of arg — that is, ellint_2(arg, π/2) — returned to you like a little math gift 🎀

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💀 Error handling 💀

Errors may be reported as specified in math_errhandling. Keep that in mind, bestie, because math does have rules even when it’s being iconic.

• If the argument is NaN, NaN is returned and domain error is not reported.
• If |arg| > 1, a domain error may occur. So yeah, watch out for that 🫶

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🎀 Notes 🎀

Implementations that do not support TR 29124 but support TR 19768 provide this function in the header tr1/cmath and namespace std::tr1. Cute, right? An implementation of this function is also available in boost.math. Obsessed with the options 💅

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✨ Example ✨

This works as shown with gcc 6.0 — literally, that’s the note, bestie:

// Run this code

#define __STDCPP_WANT_MATH_SPEC_FUNCS__ 1
#include <cmath>
#include <iostream>

int main()
{
    double hpi = std::acos(-1) / 2;
    std::cout << "E(0) = " << std::comp_ellint_2(0) << '\n'
              << "π/2 = " << hpi << '\n'
              << "E(0.5) = " << std::comp_ellint_2(0.5) << '\n'
              << "E(0.5, π/2) = " << std::ellint_2(0.5, hpi) << '\n';
}

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👑 Output 👑

E(0) = 1.5708
π/2 = 1.5708
E(0.5) = 1.46746
E(0.5, π/2) = 1.46746

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🧚 External links 🧚

Weisstein, Eric W. "Complete Elliptic Integral of the Second Kind." From MathWorld--A Wolfram Web Resource.

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💜 See also 💜

• ellint_2 — (incomplete) elliptic integral of the second kind
• ellint_2f — (function)
• ellint_2l

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And that’s the page, bestie 💅✨ This little masterpiece came from http://cppreference.com, dated 2024.06.10, with the footer handle std::comp_e...p_ellint_2l(3). Byeeee 🫶🌸