Switch to union mode if intersection fails

src/daxs/scans.py

@@ -453,10 +453,20 @@ class Scans:
                 f"size = {axis.size:d}, step = {step(axis):.8f}."
             )
             logger.debug(message)
+
             if np.array_equal(common_axis, axis):
                 continue
+
             common_axis = arrays.merge(common_axis, axis, mode=mode)
 
+            if common_axis.size == 0 and mode == "intersection":
+                message = (
+                    f"Common axis is empty after merging scan {self.scans[i].label}. "
+                    "Switching to union mode in common axis search."
+                )
+                logger.warning(message)
+                return self.get_common_axis(label, mode="union")
+
         message = (
             f"Common axis parameters using {mode} mode: "
             f"start = {common_axis[0]:.8f}, stop = {common_axis[-1]:.8f}, "