find_whole.hpp

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/*################################################################################
  ##
  ##   Copyright (C) 2016-2023 Keith O'Hara
  ##
  ##   This file is part of the GCE-Math C++ library.
  ##
  ##   Licensed under the Apache License, Version 2.0 (the "License");
  ##   you may not use this file except in compliance with the License.
  ##   You may obtain a copy of the License at
  ##
  ##       http://www.apache.org/licenses/LICENSE-2.0
  ##
  ##   Unless required by applicable law or agreed to in writing, software
  ##   distributed under the License is distributed on an "AS IS" BASIS,
  ##   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  ##   See the License for the specific language governing permissions and
  ##   limitations under the License.
  ##
  ################################################################################*/
 
/*
 * find the whole number part of x = n + r, where -0.5 <= r <= 0.5
 */
 
#ifndef _gcem_find_whole_HPP
#define _gcem_find_whole_HPP
 
namespace gcem
{
 
namespace internal
{
 
template<typename T>
constexpr
llint_t
find_whole(const T x)
noexcept
{
    return( abs(x - internal::floor_check(x)) >= T(0.5) ? \
            // if 
                static_cast<llint_t>(internal::floor_check(x) + sgn(x)) :
            // else 
                static_cast<llint_t>(internal::floor_check(x)) );
}
 
}
 
}
 
#endif