GsfMaterialMixtureConvolution, use std::array to keep track of which...

GsfMaterialMixtureConvolution, use std::array to keep track of which components are merged given we use std::array for the components per-se

Tracking/TrkFitter/TrkGaussianSumFilter/TrkGaussianSumFilter/KLGaussianMixtureReduction.h

@@ -107,6 +107,11 @@ struct Component1DArray
   int32_t numComponents = 0;
 };
 
+/* typedef tracking which component has been merged
+ */
+
+using IsMergedArray = std::array<bool,GSFConstants::maxComponentsAfterConvolution>; 
+
 /**
  * @brief Merge the componentsIn and return
  * which componets got merged

Tracking/TrkFitter/TrkGaussianSumFilter/src/GsfMaterialMixtureConvolution.cxx

@@ -349,7 +349,7 @@ Trk::GsfMaterialMixtureConvolution::update(
   // Merge components
   MultiComponentStateAssembler::Cache assemblerCache;
   int nMerges(0);
-  std::vector<bool> isMerged(n, false);
+  GSFUtils::IsMergedArray isMerged={};
   for (const auto& mergePair : merges) {
     const int8_t mini = mergePair.first;
     const int8_t minj = mergePair.second;