ERF(3M)             UNIX Programmer's Manual		  ERF(3M)



NAME
     erf, erfc - error functions

SYNOPSIS
     #include <math.h>

     double erf(x)
     double x;

     double erfc(x)
     double x;

DESCRIPTION
     Erf(x) returns the error function of x; where

     erf(x) = 2/sqrt(pi)*integral from 0 to x of exp(-t*t) dt.

     Erfc(x) returns 1.0-erf(x).

     The entry for erfc is provided because of the extreme loss
     of relative accuracy if erf(x) is called for large x and the
     result subtracted from 1.	(e.g. for x = 10, 12 places are
     lost).

SEE ALSO
     math(3M)





























Printed 11/26/99	  May 12, 1986				1