Fix to bug 1729: no bias regularization for BFGS not working (#1794)

* fix to bug 1729 * fix to bug 1729
VowpalWabbit · Mar 20, 2019 · 5a8c495 · 5a8c495
1 parent 4c8d6d2
commit 5a8c495
Showing 1 changed file with 5 additions and 4 deletions.
diff --git a/vowpalwabbit/bfgs.cc b/vowpalwabbit/bfgs.cc
@@ -457,18 +457,19 @@ double add_regularization(vw& all, bfgs& b, float regularization, T& weights)
     }
 
   // if we're not regularizing the intercept term, then subtract it off from the result above
+  // when accessing weights[constant], always use weights.strided_index(constant)
   if (all.no_bias)
   {
     if (b.regularizers == nullptr)
     {
-      (&weights[constant])[W_GT] -= regularization * weights[constant];
-      ret -= 0.5 * regularization * (weights[constant]) * (weights[constant]);
+      (&weights.strided_index(constant))[W_GT] -= regularization * (weights.strided_index(constant));
+      ret -= 0.5 * regularization * (weights.strided_index(constant)) * (weights.strided_index(constant));
     }
     else
     {
       uint64_t i = constant >> weights.stride_shift();
-      weight delta_weight = weights[constant] - b.regularizers[2 * i + 1];
-      (&weights[constant])[W_GT] -= b.regularizers[2 * i] * delta_weight;
+      weight delta_weight = (weights.strided_index(constant)) - b.regularizers[2 * i + 1];
+      (&weights.strided_index(constant))[W_GT] -= b.regularizers[2 * i] * delta_weight;
       ret -= 0.5 * b.regularizers[2 * i] * delta_weight * delta_weight;
     }
   }