整理

include/boost/numeric/odeint/util/split_adaptor.hpp

@@ -0,0 +1,103 @@
+/*
+ [auto_generated]
+ boost/numeric/odeint/util/split_adaptor.hpp
+
+ [begin_description]
+ A range adaptor which returns even-sized slices.
+ [end_description]
+
+ Copyright 2013 Karsten Ahnert
+ Copyright 2013 Mario Mulansky
+ Copyright 2013 Pascal Germroth
+
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or
+ copy at http://www.boost.org/LICENSE_1_0.txt)
+ */
+
+
+#ifndef BOOST_NUMERIC_ODEINT_UTIL_SPLIT_ADAPTOR_INCLUDED
+#define BOOST_NUMERIC_ODEINT_UTIL_SPLIT_ADAPTOR_INCLUDED
+
+#include <boost/numeric/odeint/tools/assert.hpp>
+#include <boost/range/adaptor/argument_fwd.hpp>
+#include <boost/range/size_type.hpp>
+#include <boost/range/iterator_range.hpp>
+#include <algorithm>
+
+namespace boost {
+namespace numeric {
+namespace odeint {
+namespace detail {
+
+/** \brief Returns the begin and end offset for a sub-range */
+inline std::pair<std::size_t, std::size_t>
+split_offsets( std::size_t total_length, std::size_t index, std::size_t parts )
+{
+    BOOST_NUMERIC_ODEINT_ASSERT( parts > 0 );
+    BOOST_NUMERIC_ODEINT_ASSERT( index < parts );
+    const std::size_t
+        slice = total_length / parts,
+        partial = total_length % parts,
+        lo = (std::min)(index, partial),
+        hi = (std::max<std::ptrdiff_t>)(0, index - partial),
+        begin_offset = lo * (slice + 1) + hi * slice,
+        length = slice + (index < partial ? 1 : 0),
+        end_offset = begin_offset + length;
+    return std::make_pair( begin_offset, end_offset );
+}
+
+/** \brief Return the sub-range `index` from a range which is split into `parts`.
+ *
+ * For example, splitting a range into three about equal-sized sub-ranges:
+ * \code
+ * sub0 = make_split_range(rng, 0, 3);
+ * sub1 = rng | split(1, 3);
+ * sub2 = rng | split(2, 3);
+ * \endcode
+ */
+template< class RandomAccessRange >
+inline iterator_range< typename range_iterator<RandomAccessRange>::type >
+make_split_range( RandomAccessRange& rng, std::size_t index, std::size_t parts )
+{
+    const std::pair<std::size_t, std::size_t> off = split_offsets(boost::size(rng), index, parts);
+    return make_iterator_range( boost::begin(rng) + off.first, boost::begin(rng) + off.second );
+}
+
+template< class RandomAccessRange >
+inline iterator_range< typename range_iterator<const RandomAccessRange>::type >
+make_split_range( const RandomAccessRange& rng, std::size_t index, std::size_t parts )
+{
+    const std::pair<std::size_t, std::size_t> off = split_offsets(boost::size(rng), index, parts);
+    return make_iterator_range( boost::begin(rng) + off.first, boost::begin(rng) + off.second );
+}
+
+
+struct split
+{
+    split(std::size_t index, std::size_t parts)
+        : index(index), parts(parts) {}
+    std::size_t index, parts;
+};
+
+template< class RandomAccessRange >
+inline iterator_range< typename range_iterator<RandomAccessRange>::type >
+operator|( RandomAccessRange& rng, const split& f )
+{
+    return make_split_range( rng, f.index, f.parts );
+}
+
+template< class RandomAccessRange >
+inline iterator_range< typename range_iterator<const RandomAccessRange>::type >
+operator|( const RandomAccessRange& rng, const split& f )
+{
+    return make_split_range( rng, f.index, f.parts );
+}
+
+
+}
+}
+}
+}
+
+#endif