diff --git a/src/myblockproblem.hh b/src/myblockproblem.hh
index ccf015d775b6fd72f6d1b8ab788ab56113e51de3..284a71f59f5a120fc6271c793e75c7a5e9486857 100644
--- a/src/myblockproblem.hh
+++ b/src/myblockproblem.hh
@@ -107,7 +107,7 @@ class MyBlockProblem<ConvexProblemTypeTEMPLATE>::IterateObject {
         if (j == m)
           localA = &(*it); // localA = &A[m][m]
         else
-          it->mmv(u[j], localb); // localb += A[m][j] * u[j]
+          it->mmv(u[j], localb); // localb -= A[m][j] * u[j]
       }
       assert(localA != NULL);