--- ray/src/px/ra_avs.c	1993/06/02 09:41:28	2.2
+++ ray/src/px/ra_avs.c	1993/06/04 14:45:59	2.3
@@ -9,6 +9,7 @@ static char SCCSid[] = "$SunId$ LBL";
  */
 
 #include  <stdio.h>
+#include  <math.h>
 #ifdef MSDOS
 #include  <fcntl.h>
 #endif