erf(3M)                                                   erf(3M)



NAME
     erf, erfc - error function and complementary error function

SYNOPSIS
     #include <math.h>

     double erf (x)
     double x;

     double erfc (x)
     double x;

DESCRIPTION
     erf returns the error function of x, defined as

     2 / sqrt(Pi) * integral[0, x] exp(-(t**2)) dt

     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).

SEE ALSO
     exp(3M).































Page 1                        CX/UX Programmer's Reference Manual