diff --git a/cxxmph/mph_index.cc b/cxxmph/mph_index.cc
index afeae14..fba852e 100644
--- a/cxxmph/mph_index.cc
+++ b/cxxmph/mph_index.cc
@@ -108,7 +108,7 @@ void MPHIndex::Assigning(
     const vector<TriGraph::Edge>& edges, const vector<uint32_t>& queue) {
   uint32_t current_edge = 0;
   vector<bool> marked_vertices(n_ + 1);
-  dynamic_2bitset().swap(g_);
+  dynamic_2bitset(8, true).swap(g_);
   // Initialize vector of half nibbles with all bits set.
   dynamic_2bitset g(n_, true /* set bits to 1 */);