Suppress unused variable compiler warning in sparse subtest 3.
diff --git a/test/sparse_basic.cpp b/test/sparse_basic.cpp
index e26febe..87e171a 100644
--- a/test/sparse_basic.cpp
+++ b/test/sparse_basic.cpp
@@ -643,6 +643,7 @@
 
 template<typename SparseMatrixType>
 void big_sparse_triplet(Index rows, Index cols, double density) {
+  g_dense_op_sparse_count = 0;  // Suppresses compiler warning.
   typedef typename SparseMatrixType::StorageIndex StorageIndex;
   typedef typename SparseMatrixType::Scalar Scalar;
   typedef Triplet<Scalar,Index> TripletType;