Improve calculation of R-factor. Refs #6747.

mantidproject · Apr 4, 2013 · 0c6fdf5 · 0c6fdf5
1 parent 95d0e93
commit 0c6fdf5
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Showing 3 changed files with 24 additions and 7 deletions.
diff --git a/Code/Mantid/Framework/Kernel/inc/MantidKernel/Statistics.h b/Code/Mantid/Framework/Kernel/inc/MantidKernel/Statistics.h
@@ -52,6 +52,16 @@ namespace Mantid
       /// standard_deviation of the values
       double standard_deviation;
     };
+
+    /** R factor for powder data analysis
+      */
+    struct Rfactor
+    {
+      /// Rwp
+      double Rwp;
+      /// Rp
+      double Rp;
+    };
 
     /// Return a statistics object for the given data set
     template<typename TYPE>
@@ -63,7 +73,7 @@ namespace Mantid
     template<typename TYPE>
     std::vector<double> getModifiedZscore(const std::vector<TYPE>& data, const bool sorted=false);
     /// Return the R-factors (Rwp) of a diffraction pattern data
-    double MANTID_KERNEL_DLL getRFactor(const std::vector<double>& obsI, const std::vector<double>& calI, const std::vector<double>& obsE);
+    Rfactor MANTID_KERNEL_DLL getRFactor(const std::vector<double>& obsI, const std::vector<double>& calI, const std::vector<double>& obsE);
 
   } // namespace Kernel
 } // namespace Mantid

diff --git a/Code/Mantid/Framework/Kernel/src/Statistics.cpp b/Code/Mantid/Framework/Kernel/src/Statistics.cpp
@@ -220,10 +220,10 @@ namespace Mantid
       * @param obsI :: array of observed intensity values
       * @param calI :: array of calculated intensity values;
       * @param obsE :: array of error of the observed data;
-      * @return :: Rwp
+      * @return :: RFactor including Rp and Rwp
       *
       */
-    double getRFactor(const std::vector<double>& obsI, const std::vector<double>& calI, const std::vector<double>& obsE)
+    Rfactor getRFactor(const std::vector<double>& obsI, const std::vector<double>& calI, const std::vector<double>& obsE)
     {
       // 1. Check
       if (obsI.size() != calI.size() || obsI.size() != obsE.size())
@@ -241,6 +241,8 @@ namespace Mantid
 
       double sumnom = 0;
       double sumdenom = 0;
+      double sumrpnom = 0;
+      double sumrpdenom = 0;
 
       size_t numpts = obsI.size();
       for (size_t i = 0; i < numpts; ++i)
@@ -251,13 +253,18 @@ namespace Mantid
         double weight = 1.0/(sigma*sigma);
         double diff = obs_i - cal_i;
 
+        sumrpnom += fabs(diff);
+        sumrpdenom += fabs(cal_i);
+
         sumnom += weight*diff*diff;
         sumdenom += weight*obs_i*obs_i;
       }
 
-      double rwp = std::sqrt(sumnom/sumdenom);
+      Rfactor rfactor;
+      rfactor.Rp = std::sqrt(sumrpnom/sumrpdenom);
+      rfactor.Rwp = std::sqrt(sumnom/sumdenom);
 
-      return rwp;
+      return rfactor;
     }
 
 

diff --git a/Code/Mantid/Framework/Kernel/test/StatisticsTest.h b/Code/Mantid/Framework/Kernel/test/StatisticsTest.h
@@ -140,9 +140,9 @@ class StatisticsTest : public CxxTest::TestSuite
     calY[3] = 1.3;
     obsE[3] = 1.0;
 
-    double rwp = getRFactor(obsY, calY, obsE);
+    Rfactor rfactor = getRFactor(obsY, calY, obsE);
 
-    TS_ASSERT_DELTA(rwp, 0.1582, 0.0001);
+    TS_ASSERT_DELTA(rfactor.Rwp, 0.1582, 0.0001);
   }
 
   /** Test throw exception