diff --git a/src/basic/vx_util/num_array.h b/src/basic/vx_util/num_array.h
index 6103b4b9f4..0d78337927 100644
--- a/src/basic/vx_util/num_array.h
+++ b/src/basic/vx_util/num_array.h
@@ -57,7 +57,7 @@ class NumArray {
 
       double operator[](int) const;
 
-      const double * vals() const;
+      const std::vector<double> & vals() const;
       double * buf();
       
       int has(int, bool forward=true)    const;
@@ -128,8 +128,9 @@ class NumArray {
 
 
 inline int            NumArray::n_elements()         const { return ( e.size() ); }
-inline int            NumArray::n         ()         const { return ( e.size() ); }
-inline const double * NumArray::vals()               const { return ( e.data() ); }
+inline int            NumArray::n()                  const { return ( e.size() ); }
+inline const std::vector<double> &
+                      NumArray::vals()               const { return ( e        ); }
 inline       double * NumArray::buf()                      { return ( e.data() ); }
 inline void           NumArray::inc(int i, int v)          { e[i] += v; return;   }
 inline void           NumArray::inc(int i, double v)       { e[i] += v; return;   }