diff --git a/tp/tp6/src/pi.c b/tp/tp6/src/pi.c
index dbc7de5..efd8a2e 100644
--- a/tp/tp6/src/pi.c
+++ b/tp/tp6/src/pi.c
@@ -6,10 +6,15 @@
 void* nbDansCercleSeq( void* nbLancers )
 {
 	long nb = 0;
-	unsigned int seed;
+	struct drand48_data bf;
+	double x,y;
+	srand48_r(pthread_self(),&bf); // initialisation de la graine 
+								   // avec le numero du thread
+
 	for( long i = 0; i < (long) nbLancers; i++ ) {
-		double x = (double) rand_r(&seed) / RAND_MAX;
-		double y = (double) rand_r(&seed) / RAND_MAX;
+	drand48_r(&bf,&x);
+	drand48_r(&bf,&y);
+
 		if ( x * x + y * y <= 1.0 ) {
 			nb += 1;
 		}