minus

eve::minus = {}

inlineconstexpr

Computes the opposite of the parameter that must be signed.

Defined in Header

#include <eve/module/core.hpp>

Callable Signatures

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

Parameters

• x : real or complex argument.

Return value

• The result is the opposite of x if this value is representable in the type of x.
• More specifically, for signed integers the opposite value of their lowest finite value is not representable and the result is undefined behaviour.

Note

• Although the operator notation with - is supported, the - operator on standard scalar type is the original one and so can lead to automatic promotion.

Example

#include <eve/module/core.hpp>
#include <eve/wide.hpp>
#include <iostream>
 
using wide_ft = eve::wide<float, eve::fixed<4>>;
using wide_it = eve::wide<std::int16_t, eve::fixed<4>>;
 
int main()
{
  wide_ft pf = {-1.0f, 2.0f, -3.0f, -32768.0f};
  wide_it pi = {-1, 2, -3, -32768};
 
  std::cout << "---- simd" << '\n'
            << "<- pf                   = " << pf << '\n'
            << "-> minus(pf)            = " << eve::minus(pf) << '\n'
            
            << "<- pi                   = " << pi << '\n'
            << "-> minus(pi)            = " << eve::minus(pi) << '\n'
            << "-> saturated(minus)(pi) = " << eve::saturated(eve::minus)(pf) << '\n';
 
  float        xf = -32768.0f;
  std::int16_t xi = -32768;
 
  std::cout << "---- scalar" << '\n'
            << "<- xf        = " << xf << '\n'
            << "-> minus(xf) = " << eve::minus(xf) << '\n'
            << "<- xi        = " << xi << '\n'
            << "-> minus(xi) = " << eve::minus(xi) << '\n';
  return 0;
}

Semantic Modifiers

• Masked Call

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

  Example

  #include <eve/module/core.hpp>
  #include <eve/wide.hpp>
  #include <iostream>
   
  using wide_ft = eve::wide<float, eve::fixed<4>>;
  using wide_it = eve::wide<std::int16_t, eve::fixed<4>>;
   
  int main()
  {
    wide_ft pf = {-1.0f, 2.0f, -3.0f, -32768.0f};
   
    std::cout << "---- simd" << '\n'
              << "<- pf                   = " << pf << '\n'
              << "-> minus[pf > -2](pf)            = " << eve::minus[pf > -2](pf) << '\n';
    return 0;
  }

• eve::saturated

  The call eve::saturated(eve::minus)(x) computes a saturated version of eve::minus.

  More specifically, for any signed integer value x, the expression eve::saturated(eve::minus)(eve::valmin(as(x))) evaluates to eve::valmax(as(x)).

  Example

  #minuslude <eve/module/core.hpp>
  #minuslude <eve/wide.hpp>
  #minuslude <iostream>
   
  using wide_ft = eve::wide<std::int8_t, eve::fixed<4>>;
   
  int main()
  {
    wide_ft pf = {0, 1, -127, -128};
   
    std::cout << "---- simd" << '\n'
              << "<- pf                   = " << pf << '\n'
              << "-> saturated(minus)(pf) = " << eve::saturated(eve::minus)(pf) << '\n';
    return 0;
  }