From: abn <adrien.bruneton@cea.fr>
Date: Fri, 4 Sep 2015 12:14:45 +0000 (+0200)
Subject: Optimisation in getWeightedAverageValue(), reducing number of multiplications.
X-Git-Tag: V7_7_0b1~4^2
X-Git-Url: http://git.salome-platform.org/gitweb/?a=commitdiff_plain;h=refs%2Fheads%2Fabn%2Fweighted_avg;p=modules%2Fmed.git

Optimisation in getWeightedAverageValue(), reducing number of multiplications.
---

diff --git a/src/MEDCoupling/MEDCouplingFieldDouble.cxx b/src/MEDCoupling/MEDCouplingFieldDouble.cxx
index 3fbd09d47..ee6574469 100644
--- a/src/MEDCoupling/MEDCouplingFieldDouble.cxx
+++ b/src/MEDCoupling/MEDCouplingFieldDouble.cxx
@@ -1131,14 +1131,14 @@ double MEDCouplingFieldDouble::normMax() const
 }
 
 /*!
- * Computes sums of values of each component of \a this field wighted with
+ * Computes the weighted average of values of each component of \a this field, the weights being the
  * values returned by buildMeasureField().  
  *  \param [out] res - pointer to an array of result sum values, of size at least \a
  *         this->getNumberOfComponents(), that is to be allocated by the caller.
- *  \param [in] isWAbs - if \c true (default), \c abs() is applied to the weighs computed by
- *         buildMeasureField() that makes this method slower. If a user is sure that all
- *         cells of the underlying mesh have correct orientation, he can put \a isWAbs ==
- *         \c false that speeds up this method.
+ *  \param [in] isWAbs - if \c true (default), \c abs() is applied to the weights computed by
+ *         buildMeasureField(). It makes this method slower. If you are sure that all
+ *         the cells of the underlying mesh have a correct orientation (no negative volume), you can put \a isWAbs ==
+ *         \c false to speed up the method.
  *  \throw If the mesh is not set.
  *  \throw If the data array is not set.
  */
@@ -1150,18 +1150,19 @@ void MEDCouplingFieldDouble::getWeightedAverageValue(double *res, bool isWAbs) c
   double deno=w->getArray()->accumulate(0);
   MEDCouplingAutoRefCountObjectPtr<DataArrayDouble> arr=getArray()->deepCpy();
   arr->multiplyEqual(w->getArray());
-  std::transform(arr->begin(),arr->end(),arr->getPointer(),std::bind2nd(std::multiplies<double>(),1./deno));
   arr->accumulate(res);
+  int nCompo = getArray()->getNumberOfComponents();
+  std::transform(res,res+nCompo,res,std::bind2nd(std::multiplies<double>(),1./deno));
 }
 
 /*!
- * Computes a sum of values of a given component of \a this field wighted with
+ * Computes the weighted average of values of a given component of \a this field, the weights being the
  * values returned by buildMeasureField().
  *  \param [in] compId - an index of the component of interest.
- *  \param [in] isWAbs - if \c true (default), \c abs() is applied to the weighs computed by
- *         buildMeasureField() that makes this method slower. If a user is sure that all
- *         cells of the underlying mesh have correct orientation, he can put \a isWAbs ==
- *         \c false that speeds up this method.
+ *  \param [in] isWAbs - if \c true (default), \c abs() is applied to the weights computed by
+ *         buildMeasureField(). It makes this method slower. If you are sure that all
+ *         the cells of the underlying mesh have a correct orientation (no negative volume), you can put \a isWAbs ==
+ *         \c false to speed up the method.
  *  \throw If the mesh is not set.
  *  \throw If the data array is not set.
  *  \throw If \a compId is not valid.
diff --git a/src/MEDCoupling_Swig/MEDCouplingBasicsTest.py b/src/MEDCoupling_Swig/MEDCouplingBasicsTest.py
index 9fb203dfe..da4aca8b9 100644
--- a/src/MEDCoupling_Swig/MEDCouplingBasicsTest.py
+++ b/src/MEDCoupling_Swig/MEDCouplingBasicsTest.py
@@ -11784,7 +11784,7 @@ class MEDCouplingBasicsTest(unittest.TestCase):
         f.setArray(arr)
         f.checkCoherency()
         self.assertTrue(DataArrayDouble(f.integral(False)).isEqual(DataArrayDouble([-211.66121638700983,-4863.9563007698835]),1e-11))
-        self.assertTrue(DataArrayDouble(f.getWeightedAverageValue()).isEqual(DataArrayDouble([45.496085813113595,1045.496085813114]),1e-11))
+        self.assertTrue(DataArrayDouble(f.getWeightedAverageValue()).isEqual(DataArrayDouble([45.4960858131136,1045.496085813114]),1e-11))
         self.assertTrue(DataArrayDouble(f.normL1()).isEqual(DataArrayDouble([45.49608581311362,1045.496085813114]),1e-11))
         self.assertTrue(DataArrayDouble(f.normL2()).isEqual(DataArrayDouble([58.16846378340898,1046.1241521947334]),1e-11))
         pass