diff --git a/matlab/AUG/gdat_aug.m b/matlab/AUG/gdat_aug.m
index 5170f4744e3ef6a2dc7b906cdb590e0af2942f6e..df8a711bff5eb03ed6dd7f4bfcf0d53c6878d53a 100644
--- a/matlab/AUG/gdat_aug.m
+++ b/matlab/AUG/gdat_aug.m
@@ -2947,7 +2947,7 @@ Lpf_SOL = fix(Lpf_tot/i_ref);
 Lpf1_t = mod(Lpf_tot,i_ref)+1; % nb of Lpf points
 if max(Lpf1_t) > 3000
   % most probably i_ref wrong
-  i_ref = 10^fix(log10(max(Lpf1_t)));
+  i_ref = 10^fix(log10(double(max(Lpf1_t))));
   Lpf_tot = Lpf_par.value(1:NTIME); % nb of points: i_ref*nb_SOL points + nb_core
   Lpf_SOL = fix(Lpf_tot/i_ref);
   Lpf1_t = mod(Lpf_tot,i_ref)+1; % nb of Lpf points