ERF(3M)                              SysV                              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
                                                     _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 (for example, for x = 5, 12 places are lost).

DIAGNOSTICS
     Upon successful completion, the erf and erfc functions return the value
     of the error function and complementary error function, respectively.  If
     x is NaN, NaN is returned.

SEE ALSO
     exp(3M).