[j.offspec2] OffspecDetector internally row-major ()

Merging branch 'j.offspec2'  into 'main'.

See merge request !2027

Device/Detector/OffspecDetector.cpp

@@ -53,18 +53,12 @@ const Scale& OffspecDetector::axis(size_t index) const
     return *m_axes[index];
 }
 
-size_t OffspecDetector::axisBinIndex(size_t index, size_t selected_axis) const
+size_t OffspecDetector::axisBinIndex(size_t i, size_t k_axis) const
 {
-    const size_t dim = 2;
-    size_t remainder(index);
-    size_t i_axis = dim;
-    for (size_t i = 0; i < dim; ++i) {
-        --i_axis;
-        if (selected_axis == i_axis)
-            return remainder % m_axes[i_axis]->size();
-        remainder /= m_axes[i_axis]->size();
-    }
-    ASSERT_NEVER;
+    if (k_axis == 0)
+        return i % m_axes[0]->size();
+    else
+        return i / m_axes[0]->size();
 }
 
 size_t OffspecDetector::totalSize() const
@@ -99,5 +93,5 @@ size_t OffspecDetector::indexOfSpecular(double alpha, double phi) const
 
 size_t OffspecDetector::getGlobalIndex(size_t x, size_t y) const
 {
-    return x * axis(1).size() + y;
+    return y * axis(0).size() + x;
 }

Sim/Simulation/OffspecSimulation.cpp

@@ -133,20 +133,23 @@ size_t OffspecSimulation::nElements() const
 Datafield OffspecSimulation::packResult()
 {
     const size_t ns = m_scan->nScan();
-    const size_t ny = m_detector->axis(1).size();
-    const size_t Ndet = m_detector->axis(0).size() * ny;
-    std::vector<double> out(ns * ny, 0.);
+    const size_t nphi = m_detector->axis(0).size();
+    const size_t nalp = m_detector->axis(1).size();
+    const size_t Ndet = nalp * nphi;
+    std::vector<double> out(ns * nalp, 0.);
 
     // Apply detector resolution and transfer detector image
     for (size_t j = 0; j < ns; ++j) {
 
         // TODO restore resolution m_detector->applyDetectorResolution(&detector_image);
 
-        for (size_t i = 0; i < Ndet; ++i) {
-            double& val = out[j * ny + i % ny];
-            val += m_cache[j * Ndet + i];
+        for (size_t ia = 0; ia < nalp; ++ia) {
+            double val = 0;
+            for (size_t ip = 0; ip < nphi; ++ip)
+                val += m_cache[j * Ndet + ia * nphi + ip];
             if (background())
                 val = background()->addBackground(val);
+            out[j * nalp + ia] = val;
         }
     }