diff --git a/communication_techniques/Makefile b/communication_techniques/Makefile
index 97fa3fe..bc2d5fd 100644
--- a/communication_techniques/Makefile
+++ b/communication_techniques/Makefile
@@ -1,61 +1,67 @@
 # Directories
-OBJDIR=obj
-BINDIR=bin
-SRCDIR=src
-INCDIR=include
-LIBDIR=lib
-LOGDIR=logs
-LOCALDIR=$(HOME)/local
-PAPIHIGHLEVELLIBDIR=lib
-PAPIHIGHLEVELINCDIR=include
+OBJDIR:=obj
+BINDIR:=bin
+SRCDIR:=src
+INCDIR:=include
+LIBDIR:=lib
+LOGDIR:=logs
+LOCALDIR:=$(HOME)/local
+PAPIHIGHLEVELLIBDIR:=lib
+PAPIHIGHLEVELINCDIR:=include
+CALCDIR:=calculation
 
 # Compilation flags
 # I know -finline-functions and -finline-functions-called-once are enabled by
 # -O3 but I did this in case gcc behaviour change one day
-CFLAGS=-g -O3 -finline-functions -finline-functions-called-once -Wall -Werror
-LDFLAGS=-L$(LIBDIR) -L$(LOCALDIR)/$(PAPIHIGHLEVELLIBDIR) -Wl,-rpath-link,$(HOME)/local/lib -lpthread -lpapihighlevel -ldl
+CFLAGS:=-g -O3 -finline-functions -finline-functions-called-once -Wall -Werror
+LDFLAGS:=-L$(LIBDIR) -L$(LOCALDIR)/$(PAPIHIGHLEVELLIBDIR) -Wl,-rpath-link,$(HOME)/local/lib -lpthread -lpapihighlevel -ldl
 
 # Executables
 CC=gcc
 
 # Files
-BINNAMES=asm_cache_comm c_cache_comm pipe_comm shared_mem_comm shared_mem_opt_comm jikes_barrier_comm fake_comm
-BINS=$(patsubst %, $(BINDIR)/%, $(BINNAMES))
-MAIN_OBJS=main.o common.o
-COMMON_LIB_OBJS=common.o
+BINNAMES:=asm_cache_comm c_cache_comm pipe_comm shared_mem_comm shared_mem_opt_comm jikes_barrier_comm fake_comm
+CALCLIBSNAMES:=calc_mat
+BINS:=$(patsubst %,$(BINDIR)/%,$(BINNAMES))
+CALCLIBS:=$(patsubst %,$(LIBDIR)/lib%.so.1,$(CALCLIBSNAMES))
+MAIN_OBJS:=main.o common.o
+COMMON_LIB_OBJS:=common.o
 
-.PHONY: all tidy clean distclean symlink
+.PHONY: all tidy clean distclean
 .SECONDARY: 
 .SUFFIXES: .c .o
 
-default: $(BINS)
-
-ifneq (,$(findstring $(MAKECMDGOALS),$(BINS)))
-BASE_TARGET=$(patsubst $(BINDIR)/%_comm,%,$(MAKECMDGOALS))
+default: $(BINS) $(CALCLIBS)
 
 # Compilation of binary
-$(BINDIR)/$(BASE_TARGET)_comm: $(patsubst %,$(OBJDIR)/$(BASE_TARGET)_%,$(MAIN_OBJS)) $(LIBDIR)/lib$(BASE_TARGET).a
+$(BINDIR)/%_comm: $(patsubst %,$(OBJDIR)/\%/%,$(MAIN_OBJS)) $(LIBDIR)/lib%.a
 	if [ ! -d $(BINDIR) ] ; then mkdir $(BINDIR) ; fi
 	$(CC) -o $@ $^ $(LDFLAGS)
 
-# Compilation of library
-$(LIBDIR)/lib$(BASE_TARGET).a: $(OBJDIR)/$(BASE_TARGET).o $(patsubst %,$(OBJDIR)/$(BASE_TARGET)_%,$(COMMON_LIB_OBJS))
+# Creation of comm library
+$(LIBDIR)/lib%.a: $(OBJDIR)/%.o $(patsubst %,$(OBJDIR)/\%/%,$(COMMON_LIB_OBJS))
 	if [ ! -d $(LIBDIR) ] ; then mkdir $(LIBDIR) ; fi
 	$(AR) -rcus $@ $^
 
-# Compile common source files
-$(OBJDIR)/$(BASE_TARGET)_%.o: $(SRCDIR)/%.c symlink
-	if [ ! -d $(OBJDIR) ] ; then mkdir $(OBJDIR) ; fi
-	$(CC) $(CFLAGS) -I$(INCDIR) -I$(LOCALDIR)/$(PAPIHIGHLEVELINCDIR) -c $< -o $@
-endif
+# Creation of calc library
+$(LIBDIR)/libcalc_%.so.1: $(OBJDIR)/$(CALCDIR)/calc_%.o
+	if [ ! -d $(LIBDIR) ] ; then mkdir $(LIBDIR) ; fi
+	$(CC) $(LDFLAGS) -shared -Wl,-soname,libcalc_$*.so.1 -o $@ $<
 
-# Compile non common source files
-$(OBJDIR)/%.o: $(SRCDIR)/%.c symlink
+# Compile lib specific source files
+$(OBJDIR)/%.o: $(SRCDIR)/%.c $(INCDIR)/%_comm.h $(INCDIR)/commtech.h
 	if [ ! -d $(OBJDIR) ] ; then mkdir $(OBJDIR) ; fi
+	cd $(INCDIR) ; ln -sfT $*_comm.h specific_comm.h
 	$(CC) $(CFLAGS) -I$(INCDIR) -c $< -o $@
 
-symlink:
-	ln -sfT $(BASE_TARGET)_comm.h $(INCDIR)/specific_comm.h
+# Rule for compiling common source files using libcomm is at the end of
+# this file, after the .SECONDEXPANSION target
+
+# Compile source files not using libcomm
+$(OBJDIR)/$(CALCDIR)/%.o: $(SRCDIR)/$(CALCDIR)/%.c
+	if [ ! -d $(OBJDIR) ] ; then mkdir $(OBJDIR) ; fi
+	if [ ! -d $(OBJDIR)/$(CALCDIR) ] ; then mkdir $(OBJDIR)/$(CALCDIR) ; fi
+	$(CC) $(CFLAGS) -I$(INCDIR) -c $< -o $@
 
 #.%.d: %.c
 #	gcc $(CFLAGS) -MM $^ | sed -e 's/\([^:]*\):\(.*\)/\1 $@: \2 Makefile/' > $@
@@ -82,3 +88,13 @@ distclean: clean
 #endif
 #endif
 #endif
+
+.SECONDEXPANSION:
+
+# Compile common source files using libcomm
+$(OBJDIR)/%.o: $(SRCDIR)/$$(*F).c $(INCDIR)/$$(*D)_comm.h $(INCDIR)/commtech.h
+	if [ ! -d $(OBJDIR) ] ; then mkdir $(OBJDIR) ; fi
+	if [ ! -d $(OBJDIR)/$(*D) ] ; then mkdir $(OBJDIR)/$(*D) ; fi
+	cd $(INCDIR) ; ln -sfT $(*D)_comm.h specific_comm.h
+	$(CC) $(CFLAGS) -I$(INCDIR) -I$(LOCALDIR)/$(PAPIHIGHLEVELINCDIR) -c $< -o $@
+
diff --git a/communication_techniques/src/calculation/calc_mat.c b/communication_techniques/src/calculation/calc_mat.c
new file mode 100644
index 0000000..b551ade
--- /dev/null
+++ b/communication_techniques/src/calculation/calc_mat.c
@@ -0,0 +1,40 @@
+#include <stdlib.h>
+
+
+#define likely(x) __builtin_expect(!!(x), 1)
+#define unlikely(x) __builtin_expect(!!(x), 0)
+
+
+static int *mat, *vect;
+static int li;
+static int n = 16, m = 16; /* Size of the matrice: n lines, m columns */
+
+void init_calc(void)
+{
+	int i;
+
+	srand(42);
+	mat = (int *) malloc(n * m * sizeof(int));
+	vect = (int *) malloc(m * sizeof(int));
+	for (i = 0; i < n * m; i++)
+		mat[i] = rand();
+	li = 0;
+}
+
+void *do_calc(void)
+{
+	int co, p = 0;
+
+	for (co = 0; co < m; co++)
+		p += mat[li * m + co] * vect[li];
+	mat[li * m] = p;
+	if (unlikely(++li >= n))
+		li = 0;
+	return &mat[li * m];
+}
+
+void end_calc(void)
+{
+	free(mat);
+	free(vect);
+}