diff options
Diffstat (limited to 'boost/compute/algorithm/transform_if.hpp')
| -rw-r--r-- | boost/compute/algorithm/transform_if.hpp | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/boost/compute/algorithm/transform_if.hpp b/boost/compute/algorithm/transform_if.hpp index 0eb0fd434e..9a98102d27 100644 --- a/boost/compute/algorithm/transform_if.hpp +++ b/boost/compute/algorithm/transform_if.hpp @@ -26,6 +26,7 @@ namespace boost { namespace compute { namespace detail { +// Space complexity: O(2n) template<class InputIterator, class OutputIterator, class UnaryFunction, class Predicate> inline OutputIterator transform_if_impl(InputIterator first, InputIterator last, @@ -53,14 +54,12 @@ inline OutputIterator transform_if_impl(InputIterator first, << predicate(first[k1.get_global_id(0)]) << " ? 1 : 0;\n"; k1.exec_1d(queue, 0, count); - // count number of elements to be copied - size_t copied_element_count = - ::boost::compute::count(indices.begin(), indices.end(), 1, queue); - // scan indices + size_t copied_element_count = (indices.cend() - 1).read(queue); ::boost::compute::exclusive_scan( indices.begin(), indices.end(), indices.begin(), queue ); + copied_element_count += (indices.cend() - 1).read(queue); // last scan element plus last mask element // copy values ::boost::compute::detail::meta_kernel k2("transform_if_do_copy"); @@ -98,6 +97,8 @@ inline discard_iterator transform_if_impl(InputIterator first, /// Copies each element in the range [\p first, \p last) for which /// \p predicate returns \c true to the range beginning at \p result. +/// +/// Space complexity: O(2n) template<class InputIterator, class OutputIterator, class UnaryFunction, class Predicate> inline OutputIterator transform_if(InputIterator first, InputIterator last, |