From cf5533c1b288ceb94caacc13eee3f7952369ae88 Mon Sep 17 00:00:00 2001
From: Johann Dreo <johann.dreo@thalesgroup.com>
Date: Mon, 8 Nov 2010 18:29:25 +0100
Subject: [PATCH] new eoAerageSizeStat class

---
 eo/NEWS               |  1 +
 eo/src/utils/eoStat.h | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/eo/NEWS b/eo/NEWS
index 359668933..50e256087 100644
--- a/eo/NEWS
+++ b/eo/NEWS
@@ -15,6 +15,7 @@
   - dual fitness class to handle feasibility of individual with guarantee that feasible fitness will always be better than unfeasible one
   - feasible fitness ratio stat
   - interquartile range stat
+  - average size of individuals stat
   - uniform(min,max) random function
   - compatibility macros for compiling paradiseo with CUDACC
   - removed old multi-objective classes, deprecated by the Paradiseo-MOEO project
diff --git a/eo/src/utils/eoStat.h b/eo/src/utils/eoStat.h
index d27520b13..b4e8c4592 100644
--- a/eo/src/utils/eoStat.h
+++ b/eo/src/utils/eoStat.h
@@ -423,6 +423,7 @@ public :
 };
 */
 
+
 //! A robust measure of dispersion (also called midspread or middle fifty) that is the difference between the third and the first quartile.
 template<class EOT>
 class eoInterquartileRangeStat : public eoStat< EOT, typename EOT::Fitness >
@@ -449,6 +450,41 @@ public:
     virtual std::string className(void) const { return "eoInterquartileRangeStat"; }
 };
 
+
+/** Compute the average size of indivudals over the population
+ *
+ * Obviously, will work only on representations that implement the (standard) "size()" method, 
+ * like any STL container.
+ */
+template<class EOT>
+class eoAverageSizeStat : public eoStat< EOT, double>
+{
+public:
+
+    using eoStat<EOT, double>::value;
+
+    eoAverageSizeStat( std::string description = "Av.Size" ) : 
+        eoStat<EOT,double>( 0.0, description ) {} // 0 by default
+
+    virtual void operator()( const eoPop<EOT> & pop ) 
+    {
+        size_t pop_size = pop.size();
+
+        std::vector<size_t> sizes;
+        sizes.reserve(pop_size);
+
+        for( unsigned int i=0, s = pop_size; i<s; ++i ) {
+            sizes.push_back( pop[i].size() );
+        }
+
+        size_t sum = std::accumulate( sizes.begin(), sizes.end(), 0 );
+
+        value() = static_cast<double>(sum) / static_cast<double>(pop_size);
+    }
+  
+    virtual std::string className(void) const { return "eoAverageSizeStat"; }
+};
+
 /** @} */
 #endif