diff --git a/crpptbx/JET/get_grids_1d.m b/crpptbx/JET/get_grids_1d.m
index 497eb6c51db33606e8584715d7ce1666d9a1cfe2..57d2be4f157a3262c53b50ae829869aba14557f1 100644
--- a/crpptbx/JET/get_grids_1d.m
+++ b/crpptbx/JET/get_grids_1d.m
@@ -52,9 +52,9 @@ for it=1:length(gdat_data.t)
   it_rt_eff = it_rt(it);
   it_vol_eff = it_vol(it);
   if (nbdim_x == 1)
-    ii=find(~isnan(gdat_data.grids_1d.rhopolnorm));
+    ii=find(isfinite(gdat_data.grids_1d.rhopolnorm));
   else
-    ii=find(~isnan(gdat_data.grids_1d.rhopolnorm(:,it)));
+    ii=find(isfinite(gdat_data.grids_1d.rhopolnorm(:,it)));
   end
   if (nbdim_x == 1)
     if length(ii)==length(gdat_data.grids_1d.rhopolnorm)