Imported existing code

libraries/include/boost/random/uniform_on_sphere.hpp

@@ -0,0 +1,87 @@
+/* boost random/uniform_on_sphere.hpp header file
+ *
+ * Copyright Jens Maurer 2000-2001
+ * 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)
+ *
+ * See http://www.boost.org for most recent version including documentation.
+ *
+ * $Id: uniform_on_sphere.hpp 52492 2009-04-19 14:55:57Z steven_watanabe $
+ *
+ * Revision history
+ *  2001-02-18  moved to individual header files
+ */
+
+#ifndef BOOST_RANDOM_UNIFORM_ON_SPHERE_HPP
+#define BOOST_RANDOM_UNIFORM_ON_SPHERE_HPP
+
+#include <vector>
+#include <algorithm>     // std::transform
+#include <functional>    // std::bind2nd, std::divides
+#include <boost/random/detail/config.hpp>
+#include <boost/random/normal_distribution.hpp>
+
+namespace boost {
+
+template<class RealType = double, class Cont = std::vector<RealType> >
+class uniform_on_sphere
+{
+public:
+  typedef RealType input_type;
+  typedef Cont result_type;
+
+  explicit uniform_on_sphere(int dim = 2) : _container(dim), _dim(dim) { }
+
+  // compiler-generated copy ctor and assignment operator are fine
+
+  void reset() { _normal.reset(); }
+
+  template<class Engine>
+  const result_type & operator()(Engine& eng)
+  {
+    RealType sqsum = 0;
+    for(typename Cont::iterator it = _container.begin();
+        it != _container.end();
+        ++it) {
+      RealType val = _normal(eng);
+      *it = val;
+      sqsum += val * val;
+    }
+#ifndef BOOST_NO_STDC_NAMESPACE
+    using std::sqrt;
+#endif
+    // for all i: result[i] /= sqrt(sqsum)
+    std::transform(_container.begin(), _container.end(), _container.begin(),
+                   std::bind2nd(std::divides<RealType>(), sqrt(sqsum)));
+    return _container;
+  }
+
+#ifndef BOOST_RANDOM_NO_STREAM_OPERATORS
+  template<class CharT, class Traits>
+  friend std::basic_ostream<CharT,Traits>&
+  operator<<(std::basic_ostream<CharT,Traits>& os, const uniform_on_sphere& sd)
+  {
+    os << sd._dim;
+    return os;
+  }
+
+  template<class CharT, class Traits>
+  friend std::basic_istream<CharT,Traits>&
+  operator>>(std::basic_istream<CharT,Traits>& is, uniform_on_sphere& sd)
+  {
+    is >> std::ws >> sd._dim;
+    sd._container.resize(sd._dim);
+    return is;
+  }
+#endif
+
+private:
+  normal_distribution<RealType> _normal;
+  result_type _container;
+  int _dim;
+};
+
+} // namespace boost
+
+#endif // BOOST_RANDOM_UNIFORM_ON_SPHERE_HPP