roundscale

auto eve::roundscale = functor<roundscale_t>

inlineconstexpr

Header file

#include <eve/module/core.hpp>

Callable Signatures

namespace eve
{
   // Regular overload
   constexpr auto roundscale(floating_value auto x, index_t<scale>)       noexcept; // 1
   constexpr auto roundscale(floating_value auto x, integral_value scale) noexcept; // 1
 
   // Semantic option
   constexpr auto roundscale[downward](/*any of the above overloads*/)    noexcept; // 2
   constexpr auto roundscale[upward](/*any of the above overloads*/)      noexcept; // 2
   constexpr auto roundscale[to_nearest](/*any of the above overloads*/)  noexcept; // 2
   constexpr auto roundscale[toward_zero](/*any of the above overloads*/) noexcept; // 2
}

Parameters

• x: floating value.
• scale : inttegal value or integral_constant of integral type.

Return value

1. Returns the elementwise scaled input. The number of fraction bits retained is specified by scale. By default the internal rounding after scaling is done to nearest integer. The call roundscale(x, scale) is equivalent to ldexp(eve::nearest(ldexp(x,scale), -scale))
2. with o denoting one of these options the call is equivalent to ldexp(round[o](ldexp(x,scale), -scale))`

Example

// revision 0
#include <eve/module/core.hpp>
#include <iostream>
 
int main()
{
  eve::wide wf0(0.0f, 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f);
  wf0+= 1.2345678;
  eve::wide wu0{0u, 1u, 2u, 3u, 4u, 5u, 6u, 7u};
 
  std::cout << "<- wf0                                       = " << wf0 << "\n";
  std::cout << "<- wu0                                       = " << wu0 << "\n";
 
  std::cout << "-> roundscale(wf0, index_t<0>())              = " << eve::roundscale(wf0, eve::index_t<0>()) << "\n";
  std::cout << "-> roundscale(wf0, 2*wi)                      = " << eve::roundscale(wf0, wu0) << "\n";
  std::cout << "-> roundscale[downward](wf0, index_t<0>())    = " << eve::roundscale[eve::downward](wf0, eve::index_t<0>()) << "\n";
  std::cout << "-> roundscale[upward](wf0, index_t<0>())      = " << eve::roundscale[eve::upward](wf0, eve::index_t<0>()) << "\n";
  std::cout << "-> roundscale[to_nearest](wf0, index_t<0>())  = " << eve::roundscale[eve::to_nearest](wf0, eve::index_t<0>()) << "\n";
  std::cout << "-> roundscale[toward_zero](wf0, index_t<0>()) = " << eve::roundscale[eve::toward_zero](wf0, eve::index_t<0>()) << "\n";
}