NAME
erf,
erff,
erfl,
erfc,
erfcf,
erfcl
—
error function operators
LIBRARY
Math Library (libm, -lm)
SYNOPSIS
#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);
DESCRIPTION
These functions calculate the error function of
x.
The
erf() calculates the error function of x; where
erf(x) = 2/sqrt(pi)∗integral
from 0 to x of exp(-t∗t) dt.
The
erfc() function calculates the complementary error
function of
x; that is
erfc()
subtracts the result of the error function
erf(
x) from 1.0. This is useful, since
for large
x places disappear.
SEE ALSO
math(3)
HISTORY
The
erf() and
erfc() functions appeared in
4.3BSD.