1130b656e5
This will make a number of things easier in the future, as well as (finally!) avoiding the Id-smashing problem which has plagued developers for so long. Boy, I'm glad we're not using sup anymore. This update would have been insane otherwise.
135 lines
3.3 KiB
Groff
135 lines
3.3 KiB
Groff
.\" Copyright (c) 1985, 1991 Regents of the University of California.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" from: @(#)sqrt.3 6.4 (Berkeley) 5/6/91
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.\" $FreeBSD$
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.\"
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.Dd May 6, 1991
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.Dt SQRT 3
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.Os
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.Sh NAME
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.Nm cbrt ,
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.Nm cbrtf ,
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.Nm sqrt ,
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.Nm sqrtf
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.Nd cube root and square root functions
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.Sh SYNOPSIS
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.Fd #include <math.h>
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.Ft double
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.Fn cbrt "double x"
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.Ft float
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.Fn cbrtf "float x"
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.Ft double
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.Fn sqrt "double x"
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.Ft float
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.Fn sqrtf "float x"
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.Sh DESCRIPTION
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The
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.Fn cbrt
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and the
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.Fn cbrtf
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functions compute
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the cube root of
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.Ar x .
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.Pp
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The
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.Fn sqrt
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and the
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.Fn sqrtf
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functions compute the
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non-negative square root of x.
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.Sh RETURN VALUES
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The
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.Fn cbrt
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and the
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.Fn cbrtf
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functions return the requested cube root.
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The
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.Fn sqrt
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and the
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.Fn sqrtf
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functions return the requested square root
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unless an error occurs.
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On the
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.Tn VAX
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or
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.Tn Tahoe
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processor an attempt to take the
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.Fn sqrt
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of negative
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.Fa x
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causes an error; in this event,
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the global variable
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.Va errno
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is set to
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.Dv EDOM
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and a reserved operand fault is generated.
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.Sh ERROR (due to Roundoff etc.)
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The
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.Fn cbrt
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function
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is accurate to within 0.7
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.Em ulps .
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.Pp
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The
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.Fn sqrt
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function on a
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.Tn VAX
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is accurate to within 0.501
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.Em ulps .
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Sqrt on a machine that conforms to
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.Tn IEEE
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754 is correctly rounded
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in accordance with the rounding mode in force; the error is less than
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half an
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.Em ulp
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in the default mode (round\-to\-nearest).
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An
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.Em ulp
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is one
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.Em U Ns nit
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in the
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.Em L Ns ast
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.Em P Ns lace
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carried.
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.Sh SEE ALSO
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.Xr math 3
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.Sh STANDARDS
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The
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.Nm sqrt
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function conforms to
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.St -ansiC .
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.Sh HISTORY
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The
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.Nm cbrt
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function appeared in
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.Bx 4.3 .
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