fix in case of empty shot call to gdat (for ids empty)

matlab/gdat.m

@@ -190,14 +190,18 @@ try
   % treat multiple shot numbers
   if nargin > 0 && isnumeric(shot)
     args_in = args;
-    for i=1:numel(shot)
-      args{1} = shot(i);
-      [gdat_data_i,gdat_params,error_status(i),varargout] = feval(['gdat_' lower(machine_eff)],args{:});
-      gdat_data_i.gdat_params.machine = lower(gdat_data_i.gdat_params.machine);
-      gdat_data(i) = gdat_data_i;
+    if ~isempty(shot)
+      for i=1:numel(shot)
+        args{1} = shot(i);
+        [gdat_data_i,gdat_params,error_status(i),varargout_gdat] = feval(['gdat_' lower(machine_eff)],args{:});
+        gdat_data_i.gdat_params.machine = lower(gdat_data_i.gdat_params.machine);
+        gdat_data(i) = gdat_data_i;
+      end
+    else
+      [gdat_data,gdat_params,error_status,varargout_gdat] = feval(['gdat_' lower(machine_eff)],args{:});
     end
   else
-    [gdat_data,gdat_params,error_status,varargout] = feval(['gdat_' lower(machine_eff)],args{:});
+    [gdat_data,gdat_params,error_status,varargout_gdat] = feval(['gdat_' lower(machine_eff)],args{:});
     % because data request can be an actual detailed tree related signal, upper and lower case need to be kept, but other places remain with lower case when case insensitive
     % needed since some substructure have machine name like mapping_for
     gdat_data.gdat_params.machine = lower(gdat_data.gdat_params.machine);