comparison DEPENDENCIES/generic/include/boost/accumulators/statistics/moment.hpp @ 16:2665513ce2d3

Add boost headers

+///////////////////////////////////////////////////////////////////////////////
+// moment.hpp
+//
+//  Copyright 2005 Eric Niebler. 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_ACCUMULATORS_STATISTICS_MOMENT_HPP_EAN_15_11_2005
+#define BOOST_ACCUMULATORS_STATISTICS_MOMENT_HPP_EAN_15_11_2005
+
+#include <boost/config/no_tr1/cmath.hpp>
+#include <boost/mpl/int.hpp>
+#include <boost/mpl/assert.hpp>
+#include <boost/mpl/placeholders.hpp>
+#include <boost/accumulators/framework/accumulator_base.hpp>
+#include <boost/accumulators/framework/extractor.hpp>
+#include <boost/accumulators/numeric/functional.hpp>
+#include <boost/accumulators/framework/parameters/sample.hpp>
+#include <boost/accumulators/framework/depends_on.hpp>
+#include <boost/accumulators/statistics_fwd.hpp>
+#include <boost/accumulators/statistics/count.hpp>
+
+namespace boost { namespace numeric
+{
+    /// INTERNAL ONLY
+    ///
+    template<typename T>
+    T const &pow(T const &x, mpl::int_<1>)
+    {
+        return x;
+    }
+
+    /// INTERNAL ONLY
+    ///
+    template<typename T, int N>
+    T pow(T const &x, mpl::int_<N>)
+    {
+        using namespace operators;
+        T y = numeric::pow(x, mpl::int_<N/2>());
+        T z = y * y;
+        return (N % 2) ? (z * x) : z;
+    }
+}}
+
+namespace boost { namespace accumulators
+{
+
+namespace impl
+{
+    ///////////////////////////////////////////////////////////////////////////////
+    // moment_impl
+    template<typename N, typename Sample>
+    struct moment_impl
+      : accumulator_base // TODO: also depends_on sum of powers
+    {
+        BOOST_MPL_ASSERT_RELATION(N::value, >, 0);
+        // for boost::result_of
+        typedef typename numeric::functional::fdiv<Sample, std::size_t>::result_type result_type;
+
+        template<typename Args>
+        moment_impl(Args const &args)
+          : sum(args[sample | Sample()])
+        {
+        }
+
+        template<typename Args>
+        void operator ()(Args const &args)
+        {
+            this->sum += numeric::pow(args[sample], N());
+        }
+
+        template<typename Args>
+        result_type result(Args const &args) const
+        {
+            return numeric::fdiv(this->sum, count(args));
+        }
+
+    private:
+        Sample sum;
+    };
+
+} // namespace impl
+
+///////////////////////////////////////////////////////////////////////////////
+// tag::moment
+//
+namespace tag
+{
+    template<int N>
+    struct moment
+      : depends_on<count>
+    {
+        /// INTERNAL ONLY
+        ///
+        typedef accumulators::impl::moment_impl<mpl::int_<N>, mpl::_1> impl;
+    };
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// extract::moment
+//
+namespace extract
+{
+    BOOST_ACCUMULATORS_DEFINE_EXTRACTOR(tag, moment, (int))
+}
+
+using extract::moment;
+
+// So that moment<N> can be automatically substituted with
+// weighted_moment<N> when the weight parameter is non-void
+template<int N>
+struct as_weighted_feature<tag::moment<N> >
+{
+    typedef tag::weighted_moment<N> type;
+};
+
+template<int N>
+struct feature_of<tag::weighted_moment<N> >
+  : feature_of<tag::moment<N> >
+{
+};
+
+}} // namespace boost::accumulators
+
+#endif