diff --git a/prism/include/dv.h b/prism/include/dv.h
index 79fba2a4..f9f48d28 100644
--- a/prism/include/dv.h
+++ b/prism/include/dv.h
@@ -71,7 +71,8 @@ double sum_double_vector_over_bdd(DdManager *ddman, double *vec, DdNode *filter,
 double sum_double_vector_over_mtbdd(DdManager *ddman, double *vec, DdNode *mult, DdNode **vars, int num_vars, ODDNode *odd);
 
 DistVector *double_vector_to_dist(double *v, int n);
-void free_dist_vector(DistVector *dv);
+void free_dist_vector(DistVector *&dv);
+void free_dv_or_dist_vector(double *&v, DistVector *&dv);
 
 //------------------------------------------------------------------------------
 
diff --git a/prism/src/dv/dv.cc b/prism/src/dv/dv.cc
index da8bd302..5a54c13c 100644
--- a/prism/src/dv/dv.cc
+++ b/prism/src/dv/dv.cc
@@ -455,11 +455,22 @@ DistVector *double_vector_to_dist(double *v, int n)
 
 // free distinct vector struct
 
-void free_dist_vector(DistVector *dv)
+void free_dist_vector(DistVector *&dv)
 {
 	free(dv->dist);
 	free(dv->ptrs);
 	free(dv);
+	dv = NULL;
+}
+
+//------------------------------------------------------------------------------
+
+// delete double array, distinct vector struct, or both
+
+void free_dv_or_dist_vector(double *&v, DistVector *&dv)
+{
+	if (v) { free(v); v = NULL; }
+	if (dv) { free_dist_vector(dv); dv = NULL; }
 }
 
 //------------------------------------------------------------------------------