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.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
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.\"
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.\" Permission is granted to make and distribute verbatim copies of this
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.\" manual provided the copyright notice and this permission notice are
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.\" preserved on all copies.
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.\"
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.\" Permission is granted to copy and distribute modified versions of this
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.\" manual under the conditions for verbatim copying, provided that the
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.\" entire resulting derived work is distributed under the terms of a
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.\" permission notice identical to this one.
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.\"
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.\" Since the Linux kernel and libraries are constantly changing, this
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.\" manual page may be incorrect or out-of-date. The author(s) assume no
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.\" responsibility for errors or omissions, or for damages resulting from
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.\" the use of the information contained herein. The author(s) may not
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.\" have taken the same level of care in the production of this manual,
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.\" which is licensed free of charge, as they might when working
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.\" professionally.
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.\"
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.\" Formatted or processed versions of this manual, if unaccompanied by
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.\" the source, must acknowledge the copyright and authors of this work.
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.\"
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.\" References consulted:
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.\" Linux libc source code
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.\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
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.\" 386BSD man pages
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.\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu)
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.\" Modified 2002-07-27 by Walter Harms
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.\" (walter.harms@informatik.uni-oldenburg.de)
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.\"
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.TH ERF 3 2002-07-27 "BSD" "Linux Programmer's Manual"
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.SH NAME
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2006-12-27 03:54:41 +00:00
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erf, erff, erfl, erfc, erfcf, erfcl \- error function and
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complementary error function
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.SH SYNOPSIS
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.nf
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.B #include <math.h>
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.sp
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.BI "double erf(double " x );
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.br
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.BI "float erff(float " x );
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.br
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.BI "long double erfl(long double " x );
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.sp
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.BI "double erfc(double " x );
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.br
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.BI "float erfcf(float " x );
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.br
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.BI "long double erfcl(long double " x );
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.sp
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.fi
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Link with \-lm.
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.SH DESCRIPTION
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2005-10-19 07:07:02 +00:00
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The \fBerf\fP() function returns the error function of \fIx\fP; defined
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as
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.TP
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2005-07-06 12:57:38 +00:00
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erf(x) = 2/sqrt(pi)* integral from 0 to x of exp(\-t*t) dt
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.PP
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The \fBerfc\fP() function returns the complementary error function of
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\fIx\fP, that is 1.0 \- erf(x).
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.SH "CONFORMING TO"
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2006-08-03 13:57:30 +00:00
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SVr4, 4.3BSD, C99.
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2006-08-04 09:41:28 +00:00
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The
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.I float
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and
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.I "long double"
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variants are requirements of C99.
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.SH "SEE ALSO"
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.BR cerf (3),
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.BR exp (3)
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