Changeset 2561

Timestamp:

Sep 25, 2011, 8:15:20 PM (11 years ago)

Author:

Peter

Message:

refs #671. Correct so mean is NaN when there is no data

File:

• trunk/yat/statistics/Averager.cc (modified) (3 diffs)

trunk/yat/statistics/Averager.cc

@@ -69 +69 @@
   double Averager::mean(void) const
   {
-    return mean_;
+    if (n_)
+      return mean_;
+    return std::numeric_limits<double>::quiet_NaN();
   }
 
@@ -106 +108 @@
   double Averager::sum_x(void)  const
   {
+    if (!n_)
+      return 0.0;
     return n_*mean_;
   }
@@ -147 +151 @@
   const Averager& Averager::operator+=(const Averager& a)
   {
-    mean_ += (n()*mean() + a.n()*a.mean()) / (n() + a.n());
-    double delta = mean_ = a.mean();
+    mean_ += (sum_x() + a.sum_x()) / (n() + a.n());
+    double delta = mean_ - a.mean();
     m2_ += a.m2_ + n()*a.n()*delta*delta/(n()+a.n());
     n_+=a.n_;