[Boost-commit] svn:boost r50312 - in trunk: boost/random libs/random

Subject: [Boost-commit] svn:boost r50312 - in trunk: boost/random libs/random
From: marshall_at_[hidden]
Date: 2008-12-17 21:37:09

Author: marshall
Date: 2008-12-17 21:37:07 EST (Wed, 17 Dec 2008)
New Revision: 50312
URL: http://svn.boost.org/trac/boost/changeset/50312

Log:
Applied patch from bug #1546
Text files modified: 
   trunk/boost/random/uniform_int.hpp |   103 +++++++++++++++++++++++---------------- 
   trunk/libs/random/random_test.cpp  |    67 ++++++++++++++++++++++++++              
   2 files changed, 128 insertions(+), 42 deletions(-)

Modified: trunk/boost/random/uniform_int.hpp
==============================================================================
--- trunk/boost/random/uniform_int.hpp	(original)
+++ trunk/boost/random/uniform_int.hpp	2008-12-17 21:37:07 EST (Wed, 17 Dec 2008)
@@ -60,6 +60,49 @@
   template<class Engine>
   result_type operator()(Engine& eng)
   {
+      return generate(eng, _min, _max, _range);
+  }
+
+  template<class Engine>
+  result_type operator()(Engine& eng, result_type n)
+  {
+      assert(n > 0);
+
+      if (n == 1)
+      {
+        return 0;
+      }
+
+      return generate(eng, 0, n - 1, n - 1);
+  }
+
+#if !defined(BOOST_NO_OPERATORS_IN_NAMESPACE) && !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)
+  template<class CharT, class Traits>
+  friend std::basic_ostream<CharT,Traits>&
+  operator<<(std::basic_ostream<CharT,Traits>& os, const uniform_int& ud)
+  {
+    os << ud._min << " " << ud._max;
+    return os;
+  }
+
+  template<class CharT, class Traits>
+  friend std::basic_istream<CharT,Traits>&
+  operator>>(std::basic_istream<CharT,Traits>& is, uniform_int& ud)
+  {
+# if BOOST_WORKAROUND(_MSC_FULL_VER, BOOST_TESTED_AT(13102292)) && BOOST_MSVC == 1400
+      return detail::extract_uniform_int(is, ud, ud.impl);
+# else
+   is >> std::ws >> ud._min >> std::ws >> ud._max;
+    ud.init();
+    return is;
+# endif
+  }
+#endif
+
+private:
+  template<class Engine>
+  static result_type generate(Engine& eng, result_type min_value, result_type max_value, range_type range)
+  {
     typedef typename Engine::result_type base_result;
     // ranges are always unsigned
     typedef typename make_unsigned<base_result>::type base_unsigned;
@@ -67,25 +110,25 @@
     const base_unsigned brange =
       random::detail::subtract<base_result>()((eng.max)(), (eng.min)());
 
-    if(_range == 0) {
-      return _min;    
-    } else if(brange == _range) {
+    if(range == 0) {
+      return min_value;    
+    } else if(brange == range) {
       // this will probably never happen in real life
       // basically nothing to do; just take care we don't overflow / underflow
       base_unsigned v = random::detail::subtract<base_result>()(eng(), bmin);
-      return random::detail::add<base_unsigned, result_type>()(v, _min);
-    } else if(brange < _range) {
+      return random::detail::add<base_unsigned, result_type>()(v, min_value);
+    } else if(brange < range) {
       // use rejection method to handle things like 0..3 --> 0..4
       for(;;) {
         // concatenate several invocations of the base RNG
         // take extra care to avoid overflows
         range_type limit;
-        if(_range == (std::numeric_limits<range_type>::max)()) {
-          limit = _range/(range_type(brange)+1);
-          if(_range % range_type(brange)+1 == range_type(brange))
+        if(range == (std::numeric_limits<range_type>::max)()) {
+          limit = range/(range_type(brange)+1);
+          if(range % range_type(brange)+1 == range_type(brange))
             ++limit;
         } else {
-          limit = (_range+1)/(range_type(brange)+1);
+          limit = (range+1)/(range_type(brange)+1);
         }
         // We consider "result" as expressed to base (brange+1):
         // For every power of (brange+1), we determine a random factor
@@ -96,18 +139,18 @@
           mult *= range_type(brange)+range_type(1);
         }
         if(mult == limit)
-          // _range+1 is an integer power of brange+1: no rejections required
+          // range+1 is an integer power of brange+1: no rejections required
           return result;
-        // _range/mult < brange+1  -> no endless loop
-        result += uniform_int<range_type>(0, _range/mult)(eng) * mult;
-        if(result <= _range)
-          return random::detail::add<range_type, result_type>()(result, _min);
+        // range/mult < brange+1  -> no endless loop
+        result += uniform_int<range_type>(0, range/mult)(eng) * mult;
+        if(result <= range)
+          return random::detail::add<range_type, result_type>()(result, min_value);
       }
     } else {                   // brange > range
-      if(brange / _range > 4 /* quantization_cutoff */ ) {
+      if(brange / range > 4 /* quantization_cutoff */ ) {
         // the new range is vastly smaller than the source range,
         // so quantization effects are not relevant
-        return boost::uniform_smallint<result_type>(_min, _max)(eng);
+        return boost::uniform_smallint<result_type>(min_value, max_value)(eng);
       } else {
         // use rejection method to handle cases like 0..5 -> 0..4
         for(;;) {
@@ -115,37 +158,13 @@
             random::detail::subtract<base_result>()(eng(), bmin);
           // result and range are non-negative, and result is possibly larger
           // than range, so the cast is safe
-          if(result <= static_cast<base_unsigned>(_range))
-            return random::detail::add<base_unsigned, result_type>()(result, _min);
+          if(result <= static_cast<base_unsigned>(range))
+            return random::detail::add<base_unsigned, result_type>()(result, min_value);
         }
       }
     }
   }
 
-#if !defined(BOOST_NO_OPERATORS_IN_NAMESPACE) && !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)
-  template<class CharT, class Traits>
-  friend std::basic_ostream<CharT,Traits>&
-  operator<<(std::basic_ostream<CharT,Traits>& os, const uniform_int& ud)
-  {
-    os << ud._min << " " << ud._max;
-    return os;
-  }
-
-  template<class CharT, class Traits>
-  friend std::basic_istream<CharT,Traits>&
-  operator>>(std::basic_istream<CharT,Traits>& is, uniform_int& ud)
-  {
-# if BOOST_WORKAROUND(_MSC_FULL_VER, BOOST_TESTED_AT(13102292)) && BOOST_MSVC == 1400
-      return detail::extract_uniform_int(is, ud, ud.impl);
-# else
-   is >> std::ws >> ud._min >> std::ws >> ud._max;
-    ud.init();
-    return is;
-# endif
-  }
-#endif
-
-private:
   void init()
   {
     _range = random::detail::subtract<result_type>()(_max, _min);

Modified: trunk/libs/random/random_test.cpp
==============================================================================
--- trunk/libs/random/random_test.cpp	(original)
+++ trunk/libs/random/random_test.cpp	2008-12-17 21:37:07 EST (Wed, 17 Dec 2008)
@@ -500,6 +500,72 @@
 { }
 #endif
 
+template <typename EngineT>
+struct rand_for_random_shuffle
+{
+  explicit rand_for_random_shuffle(EngineT &engine)
+    : m_engine(engine)
+  { }
+
+  template <typename IntT>
+  IntT operator()(IntT upperBound)
+  {
+    assert(upperBound > 0);
+
+    if (upperBound == 1)
+    {
+      return 0;
+    }
+
+    typedef boost::uniform_int<IntT> distribution_type;
+    typedef boost::variate_generator<EngineT &, distribution_type> generator_type;
+
+    return generator_type(m_engine, distribution_type(0, upperBound - 1))();
+  }
+
+  EngineT &m_engine;
+        
+};
+
+// Test that uniform_int<> can be used with std::random_shuffle
+// Author: Jos Hickson
+void test_random_shuffle()
+{
+    typedef boost::uniform_int<> distribution_type;
+    typedef boost::variate_generator<boost::mt19937 &, distribution_type> generator_type;
+
+    boost::mt19937 engine1(1234);
+    boost::mt19937 engine2(1234);
+
+    rand_for_random_shuffle<boost::mt19937> referenceRand(engine1);
+
+    distribution_type dist(0,10);
+    generator_type testRand(engine2, dist);
+
+    std::vector<int> referenceVec;
+
+    for (int i = 0; i < 200; ++i)
+    {
+      referenceVec.push_back(i);
+    }
+
+    std::vector<int> testVec(referenceVec);
+
+    std::random_shuffle(referenceVec.begin(), referenceVec.end(), referenceRand);
+    std::random_shuffle(testVec.begin(), testVec.end(), testRand);
+
+    typedef std::vector<int>::iterator iter_type;
+    iter_type theEnd(referenceVec.end());
+
+    for (iter_type referenceIter(referenceVec.begin()), testIter(testVec.begin());
+         referenceIter != theEnd;
+         ++referenceIter, ++testIter)
+    {
+      BOOST_CHECK_EQUAL(*referenceIter, *testIter);
+    }
+}
+
+
 int test_main(int, char*[])
 {
 
@@ -528,6 +594,7 @@
             << std::endl;
 
   test_overflow_range();
+  test_random_shuffle();
 
   return 0;
 #else