small fix of ids summary

matlab/TCV_IMAS/tcv_get_ids_summary.m

@@ -243,12 +243,13 @@ special_fields = {'r0'}; % fields needing non-automatic treatments
 global_quantities_fieldnames = fieldnames(global_quantities);
 for i=1:numel(global_quantities_fieldnames)
   if ~any(strcmp(global_quantities_fieldnames{i},special_fields))
-    if ~isstruct(ids_summary.global_quantities.(global_quantities_fieldnames{i}).value)
+    if ~isstruct(ids_summary.global_quantities.(global_quantities_fieldnames{i}).value) && ...
+	  ~isempty(global_quantities.(global_quantities_fieldnames{i}).data)
       ids_summary.global_quantities.(global_quantities_fieldnames{i}).value = interp1( ...
           global_quantities.(global_quantities_fieldnames{i}).t,global_quantities.(global_quantities_fieldnames{i}).data, ...
           ids_summary.time,'linear',NaN);
       ids_summary.global_quantities.(global_quantities_fieldnames{i}).source = ['gdat request: ' global_quantities_desc.(global_quantities_fieldnames{i})];
-    else
+    elseif ~isempty(global_quantities.(global_quantities_fieldnames{i}).data)
       special_fields{end+1} = global_quantities_fieldnames{i};
     end
   end