ERF(3m,L)                   AIX Technical Reference                   ERF(3m,L)



-------------------------------------------------------------------------------
erf, erfc



PURPOSE

Computes the error and complementary error functions.

LIBRARY

Math Library (libm.a)

SYNTAX

#include <math.h>




                double erf (x)              double erfc (x)
                double x;                   double x;



DESCRIPTION

The erf subroutine returns the error function of x, defined as:

+-----------------------------------------------------------------------------+
|           This figure cannot be displayed properly on the screen.           |
|                      Please refer to the printed book.                      |
+-----------------------------------------------------------------------------+

The erfc subroutine returns 1.0 - erf(x).  The erfc  subroutine is provided
because of the extreme loss of relative accuracy if erf(x) is called for large
values of x and the result is subtracted from 1.0.  For example, 12 decimal
places are lost when calculating (1.0 - erf(5)).

ERROR CONDITIONS

The erf and erfc subroutines fail if the following is true:

EDOM      The value of x is NaN.

RELATED INFORMATION

In this book:  "cbrt, exp, expm1, log, log10, log1p, pow, sqrt."







Processed November 7, 1990         ERF(3m,L)                                  1