lower_bound.hpp 1.5 KB

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  1. //---------------------------------------------------------------------------//
  2. // Copyright (c) 2013 Kyle Lutz <kyle.r.lutz@gmail.com>
  3. //
  4. // Distributed under the Boost Software License, Version 1.0
  5. // See accompanying file LICENSE_1_0.txt or copy at
  6. // http://www.boost.org/LICENSE_1_0.txt
  7. //
  8. // See http://boostorg.github.com/compute for more information.
  9. //---------------------------------------------------------------------------//
  10. #ifndef BOOST_COMPUTE_ALGORITHM_LOWER_BOUND_HPP
  11. #define BOOST_COMPUTE_ALGORITHM_LOWER_BOUND_HPP
  12. #include <boost/static_assert.hpp>
  13. #include <boost/compute/lambda.hpp>
  14. #include <boost/compute/system.hpp>
  15. #include <boost/compute/command_queue.hpp>
  16. #include <boost/compute/algorithm/detail/binary_find.hpp>
  17. #include <boost/compute/type_traits/is_device_iterator.hpp>
  18. namespace boost {
  19. namespace compute {
  20. /// Returns an iterator pointing to the first element in the sorted
  21. /// range [\p first, \p last) that is not less than \p value.
  22. ///
  23. /// Space complexity: \Omega(1)
  24. ///
  25. /// \see upper_bound()
  26. template<class InputIterator, class T>
  27. inline InputIterator
  28. lower_bound(InputIterator first,
  29. InputIterator last,
  30. const T &value,
  31. command_queue &queue = system::default_queue())
  32. {
  33. BOOST_STATIC_ASSERT(is_device_iterator<InputIterator>::value);
  34. using ::boost::compute::_1;
  35. InputIterator position =
  36. detail::binary_find(first, last, _1 >= value, queue);
  37. return position;
  38. }
  39. } // end compute namespace
  40. } // end boost namespace
  41. #endif // BOOST_COMPUTE_ALGORITHM_LOWER_BOUND_HPP