E.V.E
v2023.02.15
 
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◆ catalan

auto eve::catalan = functor<catalan_t>
inlineconstexpr

Defined in Header

#include <eve/module/math.hpp>

Callable Signatures

namespace eve
{
template< eve::floating_value T > constexpr T catalan(as<T> x) noexcept;
}
constexpr auto catalan
Callable object computing the catalan constant .
Definition catalan.hpp:78
EVE Main Namespace.
Definition abi.hpp:18
Lightweight type-wrapper.
Definition as.hpp:29

Parameters

  • x : Type wrapper instance embedding the type of the constant.

Return value

The call eve::catalan(as<T>()) returns the catalan constant \(\beta(2) = \sum_0^\infty \frac{(-1)^n}{(2n+1)^2}\).

Example

#include <eve/module/math.hpp>
#include <eve/wide.hpp>
#include <iostream>
#include <iomanip>
using wide_ft = eve::wide<float>;
using wide_dt = eve::wide<double>;
template<typename T>
consteval auto constexpr_catalan() { return eve::catalan(eve::as<T>{}); }
int main()
{
wide_ft wxf([](auto i, auto){return eve::is_odd(i)?-1.f:1.f; ; });
wide_dt wxd;
std::cout << "---- simd" << std::setprecision(9) << std::endl
<< "-> catalan(as<wide_ft>()) = " << eve::catalan(eve::as<wide_ft>()) << std::endl
<< "-> catalan(as(wxf)) = " << eve::catalan(eve::as(wxf)) << std::endl
<< "-> catalan[upper](as<wide_ft>()) = " << eve::catalan[eve::upper](eve::as<wide_ft>()) << std::endl
<< "-> catalan[upper](as(wxf)) = " << eve::catalan[eve::upper](eve::as(wxf)) << std::endl
<< "-> catalan[lower](as<wide_ft>()) = " << eve::catalan[eve::lower](eve::as<wide_ft>()) << std::endl
<< "-> catalan[lower](as(wxf)) = " << eve::catalan[eve::lower](eve::as(wxf)) << std::endl
<< std::setprecision(17)
<< "-> catalan(as<wide_dt>()) = " << eve::catalan(eve::as<wide_dt>()) << std::endl
<< "-> catalan(as(wxd)) = " << eve::catalan(eve::as(wxd)) << std::endl
<< "-> catalan[upper](as<wide_dt>()) = " << eve::catalan[eve::upper](eve::as<wide_dt>()) << std::endl
<< "-> catalan[upper](as(wxd)) = " << eve::catalan[eve::upper](eve::as(wxd)) << std::endl
<< "-> catalan[lower](as<wide_dt>()) = " << eve::catalan[eve::lower](eve::as<wide_dt>()) << std::endl
<< "-> catalan[lower](as(wxd)) = " << eve::catalan[eve::lower](eve::as(wxd)) << std::endl;
float xf;
double xd;
std::cout << "---- scalar" << std::endl
<< "-> catalan(as<float>()) = " << eve::catalan(eve::as(float())) << std::endl
<< "-> catalan(as<xf)) = " << eve::catalan(eve::as(xf)) << std::endl
<< "-> catalan(as<double>()) = " << eve::catalan(eve::as(double()))<< std::endl
<< "-> catalan(as<xd)) = " << eve::catalan(eve::as(xd)) << std::endl;
std::cout << "---- masked" << std::endl
<< "<- wxf = " << wxf << std::endl
<< "-> catalan[wxf < 0.0f](as(wxf)) = " << eve::catalan[wxf < 0.0f](eve::as(wxf)) << std::endl
<< "-> catalan[ignore_first(3)](as(wxf)) = " << eve::catalan[eve::ignore_first(3)](eve::as(wxf)) << std::endl;
std::cout << "-> constexpr catalan = " << constexpr_catalan<float>() << std::endl;
return 0;
}
constexpr auto is_odd
elementwise callable returning a logical true if and only if the element value is odd.
Definition is_odd.hpp:73
Conditional expression ignoring the k first lanes from a eve::simd_value.
Definition conditional.hpp:459
Wrapper for SIMD registers.
Definition wide.hpp:70