c'tor -> initializer list; make members const

Device/Detector/DetectorContext.cpp

@@ -17,9 +17,9 @@
 #include "Device/Detector/IDetector.h"
 
 DetectorContext::DetectorContext(const IDetector* detector)
+    : m_analyzer_operator(detector->analyzer().matrix())
+    , m_active_indices(detector->active_indices())
 {
-    m_active_indices = detector->active_indices();
-    m_analyzer_operator = detector->analyzer().matrix();
     m_pixels.reserve(m_active_indices.size());
     for (auto detector_index : m_active_indices)
         m_pixels.emplace_back(detector->createPixel(detector_index));

Device/Detector/DetectorContext.h

@@ -40,9 +40,9 @@ public:
     size_t detectorIndex(size_t element_index) const;
 
 private:
-    SpinMatrix m_analyzer_operator;
+    const SpinMatrix m_analyzer_operator;
+    const std::vector<size_t> m_active_indices; //! The sequence of bin indices (unmasked, in ROI)
     OwningVector<const IPixel> m_pixels;  //! All unmasked pixels inside ROI.
-    std::vector<size_t> m_active_indices; //! The sequence of bin indices (unmasked, in ROI)
 };
 
 #endif // BORNAGAIN_DEVICE_DETECTOR_DETECTORCONTEXT_H