Re #18868 better way of reading data from raw array

Framework/DataHandling/inc/MantidDataHandling/LoadILLDiffraction.h

@@ -46,9 +46,7 @@ private:
   void init() override;
   void exec() override;
 
-  void loadDataDetails(NeXus::NXEntry&);
-  void loadDataScan(NeXus::NXEntry&);
-  void loadDetectorScan(NeXus::NXEntry&);
+  void loadDataScan();
   void loadStaticInstrument();
   void loadMovingInstrument();
   void loadMetadata();

Framework/DataHandling/src/LoadILLDiffraction.cpp

@@ -73,11 +73,7 @@ void LoadILLDiffraction::exec() {
 
   m_fileName = getPropertyValue("Filename");
 
-  // open the root node
-  NXRoot dataRoot(m_fileName);
-  NXEntry firstEntry = dataRoot.openFirstEntry();
-
-  loadDataScan(firstEntry);
+  loadDataScan();
   m_progress->report("Loaded data scan");
 
   //loadMetadata();
@@ -90,20 +86,22 @@ void LoadILLDiffraction::exec() {
 /**
 * Load the data scan
 */
-void LoadILLDiffraction::loadDataScan(NXEntry &firstEntry) {
+void LoadILLDiffraction::loadDataScan() {
 
-  std::string instName = firstEntry.getString("instrument/name");
+  // open the root node
+  NXRoot dataRoot(m_fileName);
+  NXEntry firstEntry = dataRoot.openFirstEntry();
 
   m_numberScanPoints = firstEntry.getInt("data_scan/total_steps");
 
   // read in the actual data
   NXData dataGroup = firstEntry.openNXData("data_scan/detector_data");
-  NXInt data = dataGroup.openIntData();
+  NXUInt data = dataGroup.openUIntData();
   data.load();
 
   m_numberDetectorsRead = data.dim1();
 
-  resolveInstrument(instName);
+  resolveInstrument(firstEntry.getString("instrument/name"));
 
   // read the scanned variables
   NXInt scannedVar = firstEntry.openNXInt(
@@ -145,13 +143,14 @@ void LoadILLDiffraction::loadDataScan(NXEntry &firstEntry) {
   // Assign detector counts
   for (int i = 1; i <= data.dim1(); ++i) {
     for (int j = 0; j < data.dim0(); ++j) {
-      double y = double(data()[j * data.dim1() + i - 1]);
+      unsigned int y = data(j, i - 1);
       m_outWorkspace->mutableY(i)[j] = y;
       m_outWorkspace->mutableE(i)[j] = sqrt(y);
     }
     m_outWorkspace->mutableX(i) = xAxis;
   }
 
+  dataRoot.close();
   loadStaticInstrument();
 }
 
@@ -185,21 +184,6 @@ void LoadILLDiffraction::resolveInstrument(const std::string &inst) {
         throw std::runtime_error("Unknown resolution mode for instrument " +
                                  inst);
       }
-    } else if (inst == "D4") {
-      switch (m_numberDetectorsRead) {
-        m_numberDetectorsActual = m_numberDetectorsRead;
-      case 576: {
-        m_instName = "D4a";
-        break;
-      }
-      case 1152: {
-        m_instName = "D4b";
-        break;
-      }
-      default:
-        throw std::runtime_error("Unknown resolution mode for instrument " +
-                                 inst);
-      }
     } else {
       m_instName = inst;
       m_numberDetectorsActual = m_numberDetectorsRead;

Framework/Nexus/inc/MantidNexus/NexusClasses.h

@@ -480,6 +480,8 @@ typedef NXDataSetTyped<double> NXDouble;
 typedef NXDataSetTyped<char> NXChar;
 /// The size_t dataset type
 typedef NXDataSetTyped<std::size_t> NXSize;
+/// The size_t dataset type
+typedef NXDataSetTyped<unsigned int> NXUInt;
 
 //-------------------- classes --------------------------//
 
@@ -866,6 +868,10 @@ public:
   NXFloat openFloatData() { return openData<float>(); }
   /// Opens data of int type
   NXInt openIntData() { return openData<int>(); }
+  /// Opens data of size type
+  NXSize openSizeData() { return openData<std::size_t>(); }
+  /// Opens data of unsigned int type
+  NXUInt openUIntData() { return openData<unsigned int>(); }
 };
 
 /**  Implements NXdetector Nexus class.