minus

auto eve::minus = functor<minus_t>

inlineconstexpr

Header file

#include <eve/module/core.hpp>

Callable Signatures

namespace eve
{
   // Regular overload
   constexpr auto minus(value auto x)                          noexcept; // 1
 
   // Lanes masking
   constexpr auto minus[conditional_expr auto c](value auto x) noexcept; // 2
   constexpr auto minus[logical_value auto m](value auto x)    noexcept; // 2
 
   // Semantic options
   constexpr auto minus[saturated](value auto x)               noexcept; // 3
   constexpr auto minus[mod = p](value auto x)                 noexcept; // 4
}

Parameters

• x : real argument.
• c: Conditional expression masking the operation.
• m: Logical value masking the operation.
• p: modulo p operation. p must be flint less than maxflint.

Return value

1. 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 incorrect (in this case eve::minus(valmin) is valmin).
2. The operation is performed conditionally.
3. The saturated version of eve::minus. More specifically, for any signed integer value x, the expression minus[saturated](valmin(as(x))) evaluates to valmax(as(x)).
4. compute the result in modular arithmetic. the parameter must be flint positive and less than the modulus. The modulus itself must be less than maxflint.

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. Also contrarily to - on signed scalar integral values, eve::minus is never undefined behaviour.

Example

// revision 0
#include <eve/module/core.hpp>
#include <iostream>
 
int main()
{
  eve::wide wf0{0.0, 1.0, 2.0, 3.0, -1.0, -2.0, -3.0, -4.0};
  eve::wide wi0{0, 1, 2, 3, -1, -2, -3, -4};
  eve::wide wu0{0u, 1u, 2u, 3u, 4u, 5u, 6u, 7u};
 
  std::cout << "<- wf0                        = " << wf0 << "\n";
  std::cout << "<- wi0                        = " << wi0 << "\n";
  std::cout << "<- wu0                        = " << wu0 << "\n";
                                              
  std::cout << "-> minus(wf0)                 = " << eve::minus(wf0) << "\n";
  std::cout << "-> minus[ignore_last(2)](wf0) = " << eve::minus[eve::ignore_last(2)](wf0) << "\n";
  std::cout << "-> minus[wf0 != 0](wf0)       = " << eve::minus[wf0 != 0](wf0) << "\n";
  std::cout << "-> minus(wu0)                 = " << eve::minus(wu0) << "\n";
  std::cout << "-> minus[ignore_last(2)](wu0) = " << eve::minus[eve::ignore_last(2)](wu0) << "\n";
  std::cout << "-> minus[wu0 != 0](wu0)       = " << eve::minus[wu0 != 0](wu0) << "\n";
  std::cout << "-> minus[saturated](wu0)      = " << eve::minus[eve::saturated](wu0) << "\n";
  std::cout << "-> minus(wi0)                 = " << eve::minus(wi0) << "\n";
  std::cout << "-> minus[ignore_last(2)](wi0) = " << eve::minus[eve::ignore_last(2)](wi0) << "\n";
  std::cout << "-> minus[wi0 != 0](wi0)       = " << eve::minus[wi0 != 0](wi0) << "\n";
  std::cout << "-> minus[saturated](wi0)      = " << eve::minus[eve::saturated](wi0) << "\n";
}