erf(3m) — RISC
Name
erf, erfc − error functions
Syntax
#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 follows:
erf(x) = 2/sqrt(pi)∗integral from 0 to x of exp(−t∗t) dt. }
The erfc function returns 1.0−erf(x).
The entry for the erfc function is provided because of the extreme loss of relative accuracy if erf(x) is called for large x and the result subtracted from 1. For example if x = 10, 12 places are lost.
Return Values
The erf and erfc functions return NaN when x is NaN.