dfe5233b59
The algorithm uses Newton's iterations with a crude estimate of the cube root to converge to a result. Reviewed by: bde Approved by: das
123 lines
2.9 KiB
Groff
123 lines
2.9 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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.\" 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 March 5, 2011
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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 cbrtl ,
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.Nm sqrt ,
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.Nm sqrtf ,
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.Nm sqrtl
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.Nd cube root and square root functions
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.Sh LIBRARY
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.Lb libm
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.Sh SYNOPSIS
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.In 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 long double
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.Fn cbrtl "long double 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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.Ft long double
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.Fn sqrtl "long double x"
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.Sh DESCRIPTION
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The
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.Fn cbrt ,
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.Fn cbrtf ,
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and
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.Fn cbrtl
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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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.Fn sqrtf ,
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and
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.Fn sqrtl
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functions compute the
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non-negative square root of
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.Ar x .
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.Sh RETURN VALUES
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The
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.Fn cbrt ,
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.Fn cbrtf ,
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and
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.Fn cbrtl
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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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.Fn sqrtf ,
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and
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.Fn sqrtl
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functions return the requested square root
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unless an error occurs.
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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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raises an invalid exception and causes an \*(Na to be returned
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(except that the square root of -0 is valid and equal to -0.)
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.Sh SEE ALSO
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.Xr fenv 3 ,
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.Xr math 3
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.Sh STANDARDS
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The
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.Fn cbrt ,
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.Fn cbrtf ,
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.Fn cbrtl ,
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.Fn sqrt ,
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.Fn sqrtf ,
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and
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.Fn sqrtl
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functions conform to
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.St -isoC-99 .
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.Sh HISTORY
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The
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.Fn cbrt
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function appeared in
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.Bx 4.3 .
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The
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.Fn sqrtl
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function appeared in
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.Fx 8.0 .
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The
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.Fn cbrtl
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function appeared in
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.Fx 9.0 .
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