erf(3M)                                                             erf(3M)

NAME
     erf, erfc - error function and complementary error function

SYNOPSIS
     cc [flag ...] file ... -lm [library ...]

     #include <math.h>

     double erf(double x),

     double erfc(double x);

DESCRIPTION
     erf() returns the error function of x, defined as (see the
     Programmer's Reference Manual):

     {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 which results 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
     isnan(3C), exp(3M), math(5).






























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