ERF(3) Library Functions Manual ERF(3)

erf, erfc — error function operators

#include <math.h>

double
erf(double x);

long double
erfl(long double x);

float
erff(float x);

double
erfc(double x);

long double
erfcl(long double x);

float
erfcf(float x);

These functions calculate the error function of x.

The () function calculates the error function of x; where

erf(x) = 2/sqrt(pi)∗integral from 0 to x of exp(-t∗t) dt.

The () function calculates the complementary error function of x; that is erfc() computes the difference of the error function erf(x) from 1.0. This is useful, since for large x use of erfc() avoids loss of precision due to cancellation.

erf(±0) returns ±0.

(±infinity) returns ±1.

(-infinity) returns 2.

(+infinity) returns +0.

math(3)

The erf() and erfc() functions conform to ISO/IEC 9899:2011.

December 11, 2006 BSD 4.3