diff --git a/code/makefile b/code/makefile
index 602bb5d94..f2f61aed3 100644
--- a/code/makefile
+++ b/code/makefile
@@ -10,33 +10,37 @@
 # Install fftw3 (v3.2.2 is tested) with "./configure --enable-threads --enable-float"  and "make", "make install" is not needed
 # as long as the two library files are copied to the source code directory.
 
+COMPILE_DOUBLE = -openmp -c -O3 -fpp -heap-arrays 500000000
+COMPILE_SINGLE = -openmp -c -O3 -fpp
+
+
 precision :=double
 ifeq ($(precision),single)
 cpspectral_single.exe: mpie_spectral_single.o CPFEM.a
 	ifort -openmp -o cpspectral_single.exe mpie_spectral_single.o CPFEM.a libfftw3f_threads.a libfftw3f.a constitutive.a advanced.a basics.a -lpthread
 mpie_spectral_single.o: mpie_spectral_single.f90 CPFEM.o 
-	ifort -openmp -c -O3 -heap-arrays 500000000 mpie_spectral_single.f90 
+	ifort $(COMPILE_DOUBLE) mpie_spectral_single.f90 
 
 else
 cpspectral_double.exe: mpie_spectral.o CPFEM.a
 	ifort -openmp -o cpspectral_double.exe mpie_spectral.o CPFEM.a libfftw3_threads.a libfftw3.a constitutive.a advanced.a basics.a -lpthread
 mpie_spectral.o: mpie_spectral.f90 CPFEM.o 
-	ifort -openmp -c -O3 -heap-arrays 500000000 mpie_spectral.f90 
+	ifort $(COMPILE_DOUBLE) mpie_spectral.f90 
 endif
 
 CPFEM.a: CPFEM.o
 	ar rc CPFEM.a homogenization.o homogenization_RGC.o homogenization_isostrain.o crystallite.o CPFEM.o constitutive.o
 
 CPFEM.o: CPFEM.f90 homogenization.o
-	ifort -openmp -c -O3 -heap-arrays 500000000 CPFEM.f90
+	ifort $(COMPILE_DOUBLE) CPFEM.f90
 homogenization.o: homogenization.f90 homogenization_isostrain.o homogenization_RGC.o crystallite.o
-	ifort -openmp -c -O3 -heap-arrays 500000000 homogenization.f90
+	ifort $(COMPILE_DOUBLE) homogenization.f90
 homogenization_RGC.o: homogenization_RGC.f90 constitutive.a
-	ifort -openmp -c -O3 -heap-arrays 500000000 homogenization_RGC.f90
+	ifort $(COMPILE_DOUBLE) homogenization_RGC.f90
 homogenization_isostrain.o: homogenization_isostrain.f90 basics.a advanced.a
-	ifort -openmp -c -O3 -heap-arrays 500000000 homogenization_isostrain.f90
+	ifort $(COMPILE_DOUBLE) homogenization_isostrain.f90
 crystallite.o: crystallite.f90 constitutive.a
-	ifort -openmp -c -O3 -heap-arrays 500000000 crystallite.f90
+	ifort $(COMPILE_DOUBLE) crystallite.f90
 
 
 
@@ -44,22 +48,22 @@ constitutive.a: constitutive.o
 	ar rc constitutive.a constitutive.o constitutive_titanmod.o constitutive_nonlocal.o constitutive_dislotwin.o constitutive_j2.o constitutive_phenopowerlaw.o basics.a advanced.a
 
 constitutive.o: constitutive.f90 constitutive_titanmod.o constitutive_nonlocal.o constitutive_dislotwin.o constitutive_j2.o constitutive_phenopowerlaw.o
-	ifort -openmp -c -O3 -heap-arrays 500000000 constitutive.f90
+	ifort $(COMPILE_DOUBLE) constitutive.f90
 
 constitutive_titanmod.o: constitutive_titanmod.f90 basics.a advanced.a
-	ifort -openmp -c -O3 -heap-arrays 500000000 constitutive_titanmod.f90
+	ifort $(COMPILE_DOUBLE) constitutive_titanmod.f90
 
 constitutive_nonlocal.o: constitutive_nonlocal.f90 basics.a advanced.a
-	ifort -openmp -c -O3 -heap-arrays 500000000 constitutive_nonlocal.f90
+	ifort $(COMPILE_DOUBLE) constitutive_nonlocal.f90
 
 constitutive_dislotwin.o: constitutive_dislotwin.f90 basics.a advanced.a
-	ifort -openmp -c -O3 -heap-arrays 500000000 constitutive_dislotwin.f90
+	ifort $(COMPILE_DOUBLE) constitutive_dislotwin.f90
 
 constitutive_j2.o: constitutive_j2.f90 basics.a advanced.a
-	ifort -openmp -c -O3 -heap-arrays 500000000 constitutive_j2.f90
+	ifort $(COMPILE_DOUBLE) constitutive_j2.f90
 
 constitutive_phenopowerlaw.o: constitutive_phenopowerlaw.f90 basics.a advanced.a
-	ifort -openmp -c -O3 -heap-arrays 500000000 constitutive_phenopowerlaw.f90
+	ifort $(COMPILE_DOUBLE) constitutive_phenopowerlaw.f90
 
 
 
@@ -68,13 +72,13 @@ advanced.a: lattice.o
 
 
 lattice.o: lattice.f90 material.o
-	ifort -openmp -c -O3 -heap-arrays 500000000 lattice.f90
+	ifort $(COMPILE_DOUBLE) lattice.f90
 material.o: material.f90 mesh.o
-	ifort -openmp -c -O3 -heap-arrays 500000000 material.f90
+	ifort $(COMPILE_DOUBLE) material.f90
 mesh.o: mesh.f90 FEsolving.o
-	ifort -openmp -c -O3 -heap-arrays 500000000 mesh.f90
+	ifort $(COMPILE_DOUBLE) mesh.f90
 FEsolving.o: FEsolving.f90 basics.a
-	ifort -openmp -c -O3 -heap-arrays 500000000 FEsolving.f90
+	ifort $(COMPILE_DOUBLE) FEsolving.f90
 
 ifeq ($(precision),single)
 basics.a: debug.o math.o
@@ -85,25 +89,25 @@ basics.a: debug.o math.o
 endif
 
 debug.o: debug.f90 numerics.o
-	ifort -openmp -c -O3 debug.f90
+	ifort $(COMPILE_SINGLE) debug.f90
 math.o: math.f90 numerics.o
-	ifort -openmp -c -O3 math.f90
+	ifort $(COMPILE_SINGLE) math.f90
 
 numerics.o: numerics.f90 IO.o
-	ifort -openmp -c -O3 numerics.f90
+	ifort $(COMPILE_SINGLE) numerics.f90
 IO.o: IO.f90 mpie_spectral_interface.o
-	ifort -openmp -c -O3 IO.f90
+	ifort $(COMPILE_SINGLE) IO.f90
 
 ifeq ($(precision),single)
 mpie_spectral_interface.o: mpie_spectral_interface.f90 prec_single.o
-	ifort -openmp -c -O3 mpie_spectral_interface.f90
+	ifort $(COMPILE_SINGLE) mpie_spectral_interface.f90
 prec_single.o: prec_single.f90
-	ifort -openmp -c -O3 prec_single.f90
+	ifort $(COMPILE_SINGLE) prec_single.f90
 else
 mpie_spectral_interface.o: mpie_spectral_interface.f90 prec.o
-	ifort -openmp -c -O3 mpie_spectral_interface.f90
+	ifort $(COMPILE_SINGLE) mpie_spectral_interface.f90
 prec.o: prec.f90
-	ifort -openmp -c -O3 prec.f90
+	ifort $(COMPILE_SINGLE) prec.f90
 endif