rm local var

Param/Distrib/RangedDistributions.cpp

@@ -166,9 +166,7 @@ std::string RangedDistributionLogNormal::name() const
 
 IDistribution1D* RangedDistributionLogNormal::distribution_impl(double mean, double stddev) const
 {
-    const double mean_2 = mean * mean;
-
-    const double scale = std::sqrt(std::log(stddev * stddev / mean_2 + 1.0));
+    const double scale = std::sqrt(std::log(pow(stddev / mean, 2) + 1.0));
     const double median = mean * std::exp(-scale * scale / 2.0);
     return new DistributionLogNormal(median, scale);
 }