diff --git a/src/makefile b/src/makefile
index f0288b7e0a42be5a01febe8291a70e0908c576ef..6ed0367b799943482043167ac24eec15e7df1821 100644
--- a/src/makefile
+++ b/src/makefile
@@ -16,9 +16,9 @@ INC =
 # gcc:
 CMP = mpifort
 #O3: optimization
-#FLAGS   = -O3 -mcmodel=medium
+FLAGS   = -O3 -mcmodel=medium
 #debugging:
-FLAGS   = -g3 -O0 -fbounds-check -mcmodel=medium -fimplicit-none -fcheck=all -fbacktrace -floop-nest-optimize -ffpe-trap=invalid,zero,overflow -Wconversion -fno-tree-vectorize
+#FLAGS   = -g3 -O0 -fbounds-check -mcmodel=medium -fimplicit-none -fcheck=all -fbacktrace -floop-nest-optimize -ffpe-trap=invalid,zero,overflow -Wconversion -fno-tree-vectorize
 FFLAGS  = -c $(FLAGS)