Swap by default now swaps data on the default target

datahandling/serial_datahandling.py

@@ -197,7 +197,9 @@ class SerialDataHandling(DataHandling):
         arr.flags.writeable = False
         return arr
 
-    def swap(self, name1, name2, gpu=False):
+    def swap(self, name1, name2, gpu=None):
+        if gpu is None:
+            gpu = self.default_target == "gpu"
         arr = self.gpu_arrays if gpu else self.cpu_arrays
         arr[name1], arr[name2] = arr[name2], arr[name1]