diff --git a/mk/include_modules b/mk/include_modules
index b294b4d76..6c188271a 100644
--- a/mk/include_modules
+++ b/mk/include_modules
@@ -2,6 +2,10 @@
 # NO_PARMETIS = yes
 # EXEC := $(EXEC)_NOPM
 
+# Share memory communicator
+ SH_MEM_COMM = yes
+ EXEC := $(EXEC)_SH_MEM_COMM
+
 # Old nc output option (each rank dumps its own data)
 # USE_OLDIO = yes
 # EXEC := $(EXEC)_OLDIO
diff --git a/src/Makefile b/src/Makefile
index bcf1d266f..f3f2d2404 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -135,6 +135,10 @@ ifdef NO_PARMETIS
   PPFLAGS := $(PPFLAGS) $(IBMCPP)-DNO_PARMETIS
 endif
 
+ifdef SH_MEM_COMM
+  PPFLAGS := $(PPFLAGS) $(IBMCPP)-DSH_MEM_COMM
+endif
+
 ifdef USE_OLDIO
   PPFLAGS := $(PPFLAGS) $(IBMCPP)-DOLDIO
 endif