diff --git a/prod_mat_vec/main.c b/prod_mat_vec/main.c
index 875df0c24e46e7d501ecf6cf585d1475efadd2f8..200a8057a258bc1a5c2791ff489049c53acd40e2 100644
--- a/prod_mat_vec/main.c
+++ b/prod_mat_vec/main.c
@@ -45,7 +45,10 @@ void prod_mat_vec(int width, int height, float * vector_res, float ** matrix, fl
 }
 
 int main (int argc, char *argv[]) {
-    int rank, size, size_prob, w_prob, h_prob, h_base;
+    int rank, size,
+    size_prob, // problem size defined by the user (size of the matrix)
+    w_prob, // width of the matrix assigned to this processus (should be the same than the big matrix)
+    h_prob; // height of the matrix assigned to this processus
     float * vector; // processus' x vector
     float * vector_tot; // x vector agregation from all the processus
     float * vector_res; // product matrix vector's result of the current processus