MPI distrib exp: added the normal Gaussian distribution

eo/test/mpi/t-mpi-distrib-exp.cpp

@@ -97,6 +97,58 @@ class UniformDistribution : public Distribution
 
 } uniformDistribution;
 
+/**
+ * @brief Normal (gaussian) distribution of times.
+ *
+ * A normal distribution is defined by a mean and a standard deviation.
+ */
+class NormalDistribution : public Distribution
+{
+    public:
+
+    NormalDistribution() : _rng( 0 )
+    {
+        // empty
+    }
+
+    ~NormalDistribution()
+    {
+        if( _rng )
+        {
+            delete _rng;
+        }
+    }
+
+    void make_parser( eoParser & parser )
+    {
+        _active = parser.createParam( false, "normal", "Normal distribution", '\0', "Normal").value();
+        _mean = parser.createParam( 0.0, "normal-mean", "Mean for the normal distribution (0 by default), in ms.", '\0', "Normal").value();
+        double _stddev = parser.createParam( 1.0, "normal-stddev", "Standard deviation for the normal distribution (1ms by default), 0 isn't acceptable.", '\0', "Normal").value();
+
+        if( _active )
+        {
+            _rng = new eoNormalGenerator<double>( _stddev );
+        }
+    }
+
+    int next_element()
+    {
+        int next = std::floor( _mean + (*_rng)() );
+        if( next < 0 )
+        {
+            next = 0;
+        }
+        return next;
+    }
+
+    protected:
+
+    eoNormalGenerator<double> * _rng;
+
+    double _mean;
+
+} normalDistribution;
+
 int main( int argc, char** argv )
 {
     Node::init( argc, argv );