E.V.E
v2023.02.15

◆ sqrt

eve::sqrt = {}
inlineconstexpr

Computes the square root of the parameter.

Defined in Header

#include <eve/module/core.hpp>

Callable Signatures

namespace eve
{
template< eve::floating_value T >
T sqrt(T x) noexcept;
}
constexpr callable_sqrt_ sqrt
Computes the square root of the parameter.
Definition: sqrt.hpp:103
Definition: abi.hpp:18

Parameters

Return value

  1. value containing the elementwise square root of x or Nan if x is less than zero.
  2. Returns the elementwise the square root of z, in the range of the right half-plane, including the imaginary axis ( \([0, +\infty]\) along the real axis and \([-\infty, +\infty]\) along the imaginary axis.)
    • The function is continuous onto the branch cut taking into account the sign of imaginary part
    • eve::sqrt(eve::conj(z)) == eve::conj(eve::sqrt(z))
    • If z is \(\pm0\), the result is \(+0\)
    • If z is \(x+i \infty\), the result is \(\infty+i \infty\) even if x is \(NaN\)
    • If z is \(x,NaN\), the result is \(NaN,NaN\) (unless x is \(\pm\infty\))
    • If z is \(-\infty+i y\), the result is \(+0+i \infty\) for finite positive y
    • If z is \(+\infty+i y\), the result is \(+\infty+i 0\) for finite positive y
    • If z is \(-\infty+i NaN\), the result is \(NaN \pm i \infty\) (sign of imaginary part unspecified)
    • If z is \(+\infty+i NaN\), the result is \(+\infty+i NaN\)
    • If z is \(NaN+i y\), the result is \(NaN+i NaN\)
    • If z is \(NaN+i NaN\), the result is \(NaN+i NaN\)

Example

Real version

#include <eve/module/core.hpp>
#include <eve/wide.hpp>
#include <iostream>
int main()
{
wide_ft pf = {1.0f, 2.0f, -3.0f, eve::inf(eve::as<float>())};
std::cout << "---- simd" << '\n'
<< "<- pf = " << pf << '\n'
<< "-> sqrt(pf) = " << eve::sqrt(pf) << '\n'
<< "-> raw(sqrt)(pf) = " << eve::raw(eve::sqrt)(pf) << '\n';
float xf = 32.768f;
std::cout << "---- scalar" << '\n'
<< "<- xf = " << xf << '\n'
<< "-> sqrt(xf) = " << eve::sqrt(xf) << '\n';
return 0;
}
constexpr callable_inf_ inf
Computes the infinity ieee value.
Definition: inf.hpp:58
constexpr raw_type const raw
Higher-order Callable Object imbuing quick and dirty behaviour onto other Callable Objects.
Definition: raw.hpp:43
Lightweight type-wrapper.
Definition: as.hpp:29
Wrapper for SIMD registers.
Definition: wide.hpp:65

Complex version

#include <eve/module/complex.hpp>
#include <eve/wide.hpp>
#include <iostream>
int main()
{
wide_ft ref = { 0.0f, 1.0f, -1.0f, 0.5f};
wide_ft imf = { 2.0f , -1.0, -5.0, 0.0};
auto z = eve::as_complex_t<wide_ft>(ref, imf);
std::cout
<< "---- simd" << std::endl
<< "<- z = " << z << std::endl
<< "-> sqrt(z) = " << eve::sqrt(z) << std::endl;
return 0;
}

Semantic Modifiers

  • Masked Call

    The call eve;sqrt[mask](x) provides a masked version of eve::sqrt which is equivalent to if_else (mask, sqrt(x), x).

    Example

    #include <eve/module/core.hpp>
    #include <eve/wide.hpp>
    #include <iostream>
    int main()
    {
    wide_ft pf = {1.0f, 2.0f, -3.0f, eve::inf(eve::as<float>())};
    std::cout << "---- simd" << '\n'
    << "<- pf = " << pf << '\n'
    << "-> sqrt[pf > 0](pf)= " << eve::sqrt(pf) << '\n';
    return 0;
    }
  • eve::raw

    The call raw(sqrt)(x), call a proper system intrinsic if one exists, but with possibly very poor accuracy in return. Otherwise it uses the non-decorated call.