diff --git a/DIVA3D/src/Fortran/divacompile_options b/DIVA3D/src/Fortran/divacompile_options
index c7c2ea4..f0bf2c1 100644
--- a/DIVA3D/src/Fortran/divacompile_options
+++ b/DIVA3D/src/Fortran/divacompile_options
@@ -14,8 +14,8 @@ DIVA_PARALLEL=1
 # Compilation flags
 #-----------------
 
-#flags='-O3  -cpp   -DDIVAITERATIVE  ' # ' -DDIVABINARYFILESMESH -DDIVABINARYFILES '
-flags='-O3' 			# no optimization
+flags='-O3  -cpp   -DDIVAITERATIVE  ' # ' -DDIVABINARYFILESMESH -DDIVABINARYFILES '
+#flags='-O3' 			# no optimization
 
 flagscalc=' -O3 -cpp   -DDIVAITERATIVE -Wall -fbounds-check'
 # -DALLODYZERO if ZEROS in ALLODY to be forced, time consuming...