ERF(3M) UNIX Programmer's Manual ERF(3M) NNAAMMEE erf, erfc - error functions SSYYNNOOPPSSIISS ##iinncclluuddee <<mmaatthh..hh>> ddoouubbllee eerrff((xx)) ddoouubbllee xx;; ddoouubbllee eerrffcc((xx)) ddoouubbllee xx;; DDEESSCCRRIIPPTTIIOONN Erf(x) returns the error function of x; where erf(x) = 2/sqrt(pi)*integral from 0 to x of exp(-t*t) dt. Erfc(x) returns 1.0-erf(x). The entry for erfc is provided because of the extreme loss of relative accuracy if erf(x) is called for large x and the result subtracted from 1. (e.g. for x = 10, 12 places are lost). SSEEEE AALLSSOO math(3M) Printed 7/9/88 May 12, 1986 1