ERF(3M)              INTERACTIVE UNIX System              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
               The erf function returns the error function of x, defined as
               {2 over sqrt pi} int from 0 to x e sup {- t sup 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).
































          Rev. C Software Development Set                            Page 1