single_pass

Detailed Description

Tracks the index as the loop runs rather than searching afterwards.

Variables
constexpr auto	eve::algo::single_pass = ::rbr::flag(single_pass_tag {})

Variable Documentation

single_pass

auto eve::algo::single_pass = ::rbr::flag(single_pass_tag {})

inlineconstexpr

Header file #include <eve/module/algo.hpp>

namespace eve::algo
{
  inline constexpr auto single_pass = eve_implementation_defined;
}

Makes a search track the index of its candidate as the loop runs, rather than search for it afterwards. By default eve::algo::min_element and eve::algo::max_element are two passes, the value then its position, which is faster on eve's benchmarks; the trait is for a body that is expensive enough for a second pass to cost more than the tracking.

std::vector<float> data(1024);
 
// The values come from a computation: a second pass over them costs as much as the first.
auto best = min_element[single_pass](views::map(data, [](auto x) { return eve::exp(x); }));

See also

expensive_callable