simplify OffspecDetector::axisBinIndex

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 == 1)
+        return i % m_axes[1]->size();
+    else
+        return i / m_axes[1]->size();
 }
 
 size_t OffspecDetector::totalSize() const