ERF(3M)                  DOMAIN/IX SYS5                   ERF(3M)



NAME
     erf, erfc - error function and complementary error function

USAGE
     #include <math.h>

     double erf (x)
     double x;

     double erfc (x)
     double x;


DESCRIPTION
                                                     _2_x -t2
     Erf returns the error function of x, defined as   _∫e   dt.
                                                     \|π0
     Erfc, which returns 1.0 -erf(x), is provided because of the
     extreme loss of relative accuracy if erf(x) is called for
     large x and the result subtracted from 1.0 (e.g., for x = 5,
     12 places are lost).

RELATED INFORMATION
     exp(3M)





























Printed 12/4/86                                             ERF-1