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76 lines
2.4 KiB
Plaintext
76 lines
2.4 KiB
Plaintext
NAME
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isprime - whether a small integer is prime
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SYNOPSIS
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isprime(x [,err])
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TYPES
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x int
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err int
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return int
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DESCRIPTION
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Determine if x is is a small prime. This function will return
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1 if x is a small prime. If x is even, this function will
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return 0. If x is negative or a small composite (non-prime),
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0 will be returned.
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If x is a large positive odd value and the err argument is
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given, this function return err. If x is a large positive odd
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value and the err argument is not given, an error will be
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generated.
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Note that normally this function returns the integer 0 or 1.
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If err is given and x is a large positive odd value, then err
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will be returned.
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EXAMPLE
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; print isprime(-3), isprime(1), isprime(2)
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0 0 1
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; print isprime(21701), isprime(1234577), isprime(1234579)
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1 1 0
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; print isprime(2^31-9), isprime(2^31-1), isprime(2^31+11)
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0 1 1
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; print isprime(2^32+1, -1), isprime(3^99, 2), isprime(4^99, 2)
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-1 2 0
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LIMITS
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err not given and (y is even or y < 2^32)
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LINK LIBRARY
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FLAG zisprime(ZVALUE x) (return 1 if prime, 0 not prime, -1 if >= 2^32)
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SEE ALSO
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factor, lfactor, nextcand, nextprime, prevcand, prevprime,
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pfact, pix, ptest
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## Copyright (C) 1999-2006 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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## 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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##
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## @(#) $Revision: 30.1 $
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## @(#) $Id: isprime,v 30.1 2007/03/16 11:10:42 chongo Exp $
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## @(#) $Source: /usr/local/src/bin/calc/help/RCS/isprime,v $
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##
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## Under source code control: 1994/10/21 02:21:29
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## File existed as early as: 1994
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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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