NAME    [Toc]    [Back]

       erf, erfc - Error functions

SYNOPSIS    [Toc]    [Back]

       #include <math.h>

       double erf(
               double x ); float erff(
               float x ); long double erfl(
               long double x ); double erfc(
               double x ); float erfcf(
               float x ); long double erfcl(
               long double x );

LIBRARY    [Toc]    [Back]

       Math Library (libm)

STANDARDS    [Toc]    [Back]

       Interfaces  documented  on  this reference page conform to
       industry standards as follows:

       erf():  XPG4

       erfc():  XPG4

       Refer to the standards(5) reference page for more information
 about industry standards and associated tags.

DESCRIPTION    [Toc]    [Back]

       The  erf(),  erff(), and erfl() functions return the error
       function of x, where erf(x), erff(x),  and  erfl(x)  equal
       (2/sqrt(pi))  times  the  area  under the curve e**(-t**2)
       between 0 and x.

       The erfc(), erfcf(),  and erfcl() functions return (1.0  -
       erf(x)). The erfc() function can result in an underflow as
       x gets large.



                                                           erf(3)