create_total_scattering_pdf runs with no q_lims and merge_banks=flase

as q_lims is a required paramiter for the function it would raise an error
if trying to run without it, even when it is not needed for merge_Banks=false
this change automaticaly sets q_lims to none when none is given as kwargs

scripts/Diffraction/isis_powder/polaris.py

@@ -49,6 +49,8 @@ class Polaris(AbstractInst):
         return vanadium_d
 
     def create_total_scattering_pdf(self, **kwargs):
+        if not 'q_lims' in kwargs:
+            kwargs['q_lims'] = None
         self._inst_settings.update_attributes(kwargs=kwargs)
         # Generate pdf
         run_details = self._get_run_details(self._inst_settings.run_number)

scripts/Diffraction/isis_powder/polaris_routines/polaris_algs.py

@@ -163,12 +163,12 @@ def _merge_workspace_with_limits(focused_ws, q_lims):
             q_min = np.array(q_min)
             q_max = np.array(q_max)
         except IOError:
-            raise RuntimeError("q_lims is not valid")
+            raise RuntimeError("q_lims directory is not valid")
     elif type(q_lims) == list or type(q_lims) == np.ndarray:
         q_min = q_lims[0, :]
         q_max = q_lims[1, :]
     else:
-        raise RuntimeError("q_lims is not valid")
+        raise RuntimeError("q_lims type is not valid")
     bin_width = np.inf
     for i in range(q_min.size):
         pdf_x_array = focused_ws_conjoined.readX(i)

scripts/Diffraction/isis_powder/polaris_routines/polaris_param_mapping.py

@@ -28,7 +28,7 @@ attr_mapping = [
     ParamMapEntry(ext_name="mode", int_name="mode", enum_class=POLARIS_CHOPPER_MODES,
                   optional=True),
     ParamMapEntry(ext_name="multiple_scattering", int_name="multiple_scattering", optional=True),
-    ParamMapEntry(ext_name="q_lims", int_name="q_lims"),
+    ParamMapEntry(ext_name="q_lims", int_name="q_lims", optional=True),
     ParamMapEntry(ext_name="raw_data_cropping_values", int_name="raw_data_crop_values"),
     ParamMapEntry(ext_name="run_number", int_name="run_number"),
     ParamMapEntry(ext_name="sample_empty", int_name="sample_empty", optional=True),