1*61285Sbostic.\" Copyright (c) 1985, 1991, 1993 2*61285Sbostic.\" The Regents of the University of California. All rights reserved. 324695Smckusick.\" 448401Sbostic.\" %sccs.include.redist.roff% 524695Smckusick.\" 6*61285Sbostic.\" @(#)erf.3 8.1 (Berkeley) 06/04/93 748352Scael.\" 848352Scael.Dd 948352Scael.Dt ERF 3 1048352Scael.Os BSD 4.3 1148352Scael.Sh NAME 1248352Scael.Nm erf , 1348352Scael.Nm erfc 1448352Scael.Nd error function operators 1548352Scael.Sh SYNOPSIS 1648352Scael.Fd #include <math.h> 1748352Scael.Ft double 1848352Scael.Fn erf "double x" 1948352Scael.Ft double 2048352Scael.Fn erfc "double x" 2148352Scael.Sh DESCRIPTION 2248352ScaelThese functions calculate the error function of 2348352Scael.Fa x . 2448352Scael.Pp 2548352ScaelThe 2648352Scael.Fn erf 2748352Scaelcalculates the error function of x; where 2848352Scael.Bd -filled -offset indent 2924370Smiriam.if n \{\ 3024370Smiriamerf(x) = 2/sqrt(pi)\(**\|integral from 0 to x of exp(\-t\(**t) dt. \} 3124370Smiriam.if t \{\ 3224370Smiriamerf\|(x) := 3324370Smiriam(2/\(sr\(*p)\|\(is\d\s8\z0\s10\u\u\s8x\s10\d\|exp(\-t\u\s82\s10\d)\|dt. \} 3448352Scael.Ed 3548352Scael.Pp 3648352ScaelThe 3748352Scael.Fn erfc 3848352Scaelfunction calculates the complementary error function of 3948352Scael.Fa x ; 4048352Scaelthat is 4148352Scael.Fn erfc 4248401Sbosticsubtracts the result of the error function 4348352Scael.Fn erf x 4448352Scaelfrom 1.0. 4548352ScaelThis is useful, since for large 4648401Sbostic.Fa x 4748401Sbosticplaces disappear. 4848352Scael.Sh SEE ALSO 4948352Scael.Xr math 3 5048352Scael.Sh HISTORY 5148352ScaelThe 5248352Scael.Fn erf 5348352Scaeland 5448352Scael.Fn erfc 5548401Sbosticfunctions appeared in 5648352Scael.Bx 4.3 . 57