[yoda-svn] r406 - in trunk: . include/YODA src

[blackhole at projects.hepforge.org]

Author: buckley
Date: Tue Dec  6 15:26:05 2011
New Revision: 406

Log:
Adding a (weighted) RMS calculating method to Dbn1D.

Modified:
   trunk/ChangeLog
   trunk/include/YODA/Dbn1D.h
   trunk/src/Dbn1D.cc

Modified: trunk/ChangeLog
==============================================================================
--- trunk/ChangeLog	Tue Nov  8 02:29:58 2011	(r405)
+++ trunk/ChangeLog	Tue Dec  6 15:26:05 2011	(r406)
@@ -1,5 +1,9 @@
+2011-12-06  Andy Buckley  <andy.buckley at cern.ch>
+
+	* Adding a (weighted) RMS calculating method to Dbn1D.
+
 2011-09-03  Dave Mallows  <dave.mallows at gmail.com>
-	
+
 	* Fixed ReaderAIDA: x-value and low y-error interchanged when filling
 	Scatter2D.
 

Modified: trunk/include/YODA/Dbn1D.h
==============================================================================
--- trunk/include/YODA/Dbn1D.h	Tue Nov  8 02:29:58 2011	(r405)
+++ trunk/include/YODA/Dbn1D.h	Tue Dec  6 15:26:05 2011	(r406)
@@ -134,6 +134,12 @@
     /// Synonym for interface compatibility with Dbn2D
     double xStdErr() const { return stdErr(); }
 
+
+    /// Weighted RMS, \f$ \sqrt{ 1/N_\text{eff} \sum_i w_i x^2_i } \f$, of distribution.
+    double rms() const;
+    /// Synonym for interface compatibility with Dbn2D
+    double xRms() const { return rms(); }
+
     //@}
 
 

Modified: trunk/src/Dbn1D.cc
==============================================================================
--- trunk/src/Dbn1D.cc	Tue Nov  8 02:29:58 2011	(r405)
+++ trunk/src/Dbn1D.cc	Tue Dec  6 15:26:05 2011	(r406)
@@ -32,7 +32,7 @@
     // Weighted variance defined as
     // sig2 = ( sum(wx**2) * sum(w) - sum(wx)**2 ) / ( sum(w)**2 - sum(w**2) )
     // see http://en.wikipedia.org/wiki/Weighted_mean
-    if (isZero(effNumEntries(), 0.0)) {
+    if (effNumEntries() == 0) {
       throw LowStatsError("Requested width of a distribution with no net fill weights");
     } else if (fuzzyLessEquals(effNumEntries(), 1.0)) {
       throw LowStatsError("Requested width of a distribution with only one effective entry");
@@ -43,7 +43,7 @@
       throw WeightError("Undefined weighted variance");
     }
     /// @todo Isn't this sensitive to the overall scale of the weights?
-    /// Shouldn't it check if den is bigger then num by a set number of 
+    /// Shouldn't it check if den is bigger then num by a set number of
     /// orders of magnitude and vice versa?
     if (fabs(num) < 1E-10 && fabs(den) < 1E-10) {
       throw WeightError("Numerically unstable weights in width calculation");
@@ -63,6 +63,17 @@
   }
 
 
+  double Dbn1D::rms() const {
+    // Weighted RMS defined as
+    // rms = \sqrt{ 1/N_eff \sum_i w_i x^2_i }
+    if (effNumEntries() == 0) {
+      throw LowStatsError("Requested RMS of a distribution with no net fill weights");
+    }
+    const double meansq = sumWX2() / effNumEntries();
+    return std::sqrt(meansq);
+  }
+
+
   Dbn1D& Dbn1D::add(const Dbn1D& d) {
     _numFills += d._numFills;
     _sumW     += d._sumW;