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68 lines
2.1 KiB
Plaintext
68 lines
2.1 KiB
Plaintext
NAME
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factor - smallest prime factor not exceeding specified limit
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SYNOPSIS
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factor(n [, limit [, err]])
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TYPES
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n integer
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limit integer with abs(limit) < 2^32, defaults to 2^32 - 1
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err integer
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return positive integer, -1 or err
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DESCRIPTION
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If n >= 0 and n has a prime factor less than or equal to limit,
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factor(n, limit) returns the smallest such factor. If n >= 0
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and the smallest prime factor of n exceeds limit, 1 is returned.
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In particular, if n >= 0 and limit <= 1, factor(n, limit)
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always returns 1; factor(n,2) returns 2 if and only if n is even.
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If n < 0, -1 is returned.
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If abs(limit) >= 2^32, factor(n, limit) causes an error,
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factor(n, limit, err) returns the value of err.
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EXAMPLE
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> print factor(35,4), factor(35,5), factor(35), factor(-35)
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1 5 5 -1
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> print factor(2^32 + 1), factor(2^47 - 1), factor(2^59 - 1)
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641 2351 179951
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LIMITS
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none
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LINK LIBRARY
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FLAG zfactor(ZVALUE n, ZVALUE limit, ZVALUE *res)
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SEE ALSO
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lfactor
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## Copyright (C) 1999 Landon Curt Noll
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##
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## Calc is open software; you can redistribute it and/or modify it under
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## the terms of the version 2.1 of the GNU Lesser General Public License
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## as published by the Free Software Foundation.
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##
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## Calc is distributed in the hope that it will be useful, but WITHOUT
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## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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## or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
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## Public License for more details.
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##
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## A copy of version 2.1 of the GNU Lesser General Public License is
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## distributed with calc under the filename COPYING-LGPL. You should have
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## received a copy with calc; if not, write to Free Software Foundation, Inc.
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## 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
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##
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## @(#) $Revision: 29.2 $
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## @(#) $Id: factor,v 29.2 2000/06/07 14:02:33 chongo Exp $
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## @(#) $Source: /usr/local/src/cmd/calc/help/RCS/factor,v $
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##
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## Under source code control: 1995/12/18 12:34:57
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## File existed as early as: 1995
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##
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## chongo <was here> /\oo/\ http://www.isthe.com/chongo/
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## Share and enjoy! :-) http://www.isthe.com/chongo/tech/comp/calc/
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