diff --git a/src/basic/vx_math/ptile.cc b/src/basic/vx_math/ptile.cc
index 9ff068b8b1..9812403a84 100644
--- a/src/basic/vx_math/ptile.cc
+++ b/src/basic/vx_math/ptile.cc
@@ -23,6 +23,7 @@ using namespace std;
 #include "is_bad_data.h"
 
 #include "nint.h"
+#include "vx_log.h"
 
 
 ///////////////////////////////////////////////////////////////////////////////