rsqrt

eve::rsqrt = {}

inlineconstexpr

Computes the inverse of the square root of the parameter.

Defined in Header

#include <eve/module/core.hpp>

Callable Signatures

namespace eve
{
   template< eve::value T >
   T rsqrt(T x) noexcept;
}

Parameters

• x : real or complex argument.

Return value

value containing the elementwise inverse of the square root of x.

Example

#include <eve/module/core.hpp>
#include <eve/wide.hpp>
#include <iostream>
 
using wide_ft = eve::wide<float, eve::fixed<4>>;
 
int main()
{
  wide_ft pf = {1.0f, 0.5f, -3.0f, eve::inf(eve::as<float>())};
 
  std::cout << "---- simd" << '\n'
            << "<- pf               = " << pf << '\n'
            << "-> rsqrt(pf)        = " << eve::rsqrt(pf) << '\n'
            << "-> raw(rsqrt)(pf)   = " << eve::raw(eve::rsqrt)(pf) << '\n';
 
  float xf = 32.768f;
 
  std::cout << "---- scalar" << '\n'
            << "<- xf               = " << xf << '\n'
            << "-> sqrt(xf)         = " << eve::rsqrt(xf) << '\n';
 
  return 0;
}

Semantic Modifiers

• Masked Call

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

  Example

  #include <eve/module/core.hpp>
  #include <eve/wide.hpp>
  #include <iostream>
   
  using wide_ft = eve::wide<float, eve::fixed<4>>;
   
  int main()
  {
    wide_ft pf = {1.0f, 0.5f, -3.0f, eve::inf(eve::as<float>())};
   
    std::cout << "---- simd" << '\n'
              << "<- pf               = " << pf << '\n'
              << "-> rsqrt[pf > 0](pf)        = " << eve::rsqrt[pf > 0](pf) << '\n';
    return 0;
  }

• eve::raw

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