--- ray/src/rt/func.c	1991/06/17 08:51:33	1.17
+++ ray/src/rt/func.c	1991/06/19 15:08:39	1.19
@@ -33,7 +33,7 @@ OBJREC  *m;
 register RAY  *r;
 XF  *bx;
 {
-	extern double  l_arg();
+	extern double  l_arg(), l_erf(), l_erfc();
 	extern long  eclock;
 	static char  *initfile = "rayinit.cal";
 	static long  lastrno = -1;
@@ -52,6 +52,8 @@ XF  *bx;
 		scompile("Jx=$19;Jy=$20;Jz=$21;", NULL, 0);
 		scompile("Kx=$22;Ky=$23;Kz=$24;", NULL, 0);
 		funset("arg", 1, '=', l_arg);
+		funset("erf", 1, ':', l_erf);
+		funset("erfc", 1, ':', l_erfc);
 		setnoisefuncs();
 		initfile = NULL;
 	}
@@ -137,6 +139,24 @@ l_arg()				/* return nth real argument */
 
 
 double
+l_erf()				/* error function */
+{
+	extern double  erf();
+
+	return(erf(argument(1)));
+}
+
+
+double
+l_erfc()			/* cumulative error function */
+{
+	extern double  erfc();
+
+	return(erfc(argument(1)));
+}
+
+
+double
 chanvalue(n)			/* return channel n to calcomp */
 register int  n;
 {
@@ -175,8 +195,10 @@ register int  n;
 		return(sum * funcxf.sca);
 
 	}
-	if (n == 10)			/* dot product */
-		return(fray->rod);
+	if (n == 10)			/* dot product (range [-1,1]) */
+		return(	fray->rod <= -1.0 ? -1.0 :
+			fray->rod >= 1.0 ? 1.0 :
+			fray->rod );
 
 	if (n == 11)			/* scale */
 		return(funcxf.sca);