diff --git a/src/np_sphere.cpp b/src/np_sphere.cpp
index ac985ac4e8b292acd06534aad948586a61d39880..b6ba389eb191b88c11c44887522cc0f114226913 100644
--- a/src/np_sphere.cpp
+++ b/src/np_sphere.cpp
@@ -3,10 +3,13 @@
 
 #include <cstdio>
 #include <string>
+#ifndef INCLUDE_CONFIGURATION_H_
 #include "include/Configuration.h"
+#endif
 
 using namespace std;
 
+extern void cluster();
 extern void sphere();
 
 /*! \brief Main program entry point.
@@ -18,6 +21,8 @@ extern void sphere();
  * the configuration and runs the main program.
  */
 int main(int argc, char **argv) {
-	sphere();
+	bool is_sphere = true;
+	if (is_sphere) sphere();
+	else cluster();
 	return 0;
 }
diff --git a/src/sphere/Makefile b/src/sphere/Makefile
index c42d9b04f701cfb823a0c443581c96c23207d920..76e16f0b52ee8cd5e4c91254ef2bd20cd0e0e48e 100644
--- a/src/sphere/Makefile
+++ b/src/sphere/Makefile
@@ -14,8 +14,8 @@ edfb: edfb.o
 sph: sph.o
 	$(FC) $(FCFLAGS) -o $(BUILDDIR)/sph $(BUILDDIR)/sph.o $(LFLAGS)
 
-np_sphere: $(BUILDDIR)/np_sphere.o $(BUILDDIR)/Commons.o $(BUILDDIR)/Configuration.o $(BUILDDIR)/Parsers.o $(BUILDDIR)/sphere.o
-	$(CXX) $(CXXFLAGS) $(CXXLFLAGS) -o $(BUILDDIR)/np_sphere $(BUILDDIR)/np_sphere.o $(BUILDDIR)/Commons.o $(BUILDDIR)/Configuration.o $(BUILDDIR)/Parsers.o $(BUILDDIR)/sphere.o
+np_sphere: $(BUILDDIR)/np_sphere.o $(BUILDDIR)/Commons.o $(BUILDDIR)/Configuration.o $(BUILDDIR)/Parsers.o $(BUILDDIR)/sphere.o $(BUILDDIR)/cluster.o
+	$(CXX) $(CXXFLAGS) $(CXXLFLAGS) -o $(BUILDDIR)/np_sphere $(BUILDDIR)/np_sphere.o $(BUILDDIR)/Commons.o $(BUILDDIR)/Configuration.o $(BUILDDIR)/Parsers.o $(BUILDDIR)/sphere.o $(BUILDDIR)/cluster.o
 
 $(BUILDDIR)/np_sphere.o:
 	$(CXX) $(CXXFLAGS) -c ../np_sphere.cpp -o $(BUILDDIR)/np_sphere.o
@@ -29,6 +29,9 @@ $(BUILDDIR)/Configuration.o:
 $(BUILDDIR)/Parsers.o:
 	$(CXX) $(CXXFLAGS) -c ../libnptm/Parsers.cpp -o $(BUILDDIR)/Parsers.o
 
+$(BUILDDIR)/cluster.o:
+	$(CXX) $(CXXFLAGS) -c ../cluster/cluster.cpp -o $(BUILDDIR)/cluster.o
+
 $(BUILDDIR)/sphere.o:
 	$(CXX) $(CXXFLAGS) -c sphere.cpp -o $(BUILDDIR)/sphere.o