NAME

erf, erfc − error function and complementary error function

SYNOPSIS

#include <math.h>

double erf (x)
double x;

double erfc (x)
double x;

DESCRIPTION

erf returns the error function of x, defined as 2 / sqrt(Pi) ∗ integral[0, x] exp(-(t∗∗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). 

CX/UX Programmer’s Reference Manual