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69 lines
2.2 KiB
Plaintext
69 lines
2.2 KiB
Plaintext
NAME
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randbit - Blum-Blum-Shub pseudo-random number generator
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SYNOPSIS
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randombit([x])
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TYPES
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x integer
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return integer
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DESCRIPTION
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If x > 0, randombit(x) returns a pseudo-random integer in [0, 2^x),
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i.e. the same as rand(2^x). If the integer returned is
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b_1 * 2^(x-1) + b_2 * 2^(x-2) + ... + b_n,
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where each b_i is 0 or 1, then b_1, b_2, ..., b_n may be
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considered as a sequence of x random bits.
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If x <= 0, randombit(x) causes the random-number generator to skip
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abs(x) bits, and returns abs(x).
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If x is omitted, it is assumed to have the value of 1.
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See the random() help page for details on the additive 55 shuffle
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pseudo-random number generator.
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EXAMPLE
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> print srandom(0), randombit(20), randombit(20), randombit(20)
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RANDOM state 523139 567456 693508
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> print srandom(0), randombit(-20), randombit(20), randombit(-20)
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RANDOM state 20 567456 20
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LIMITS
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x != 0
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LINK LIBRARY
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void zrandom(long cnt, ZVALUE *res)
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SEE ALSO
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seed, srand, randbit, isrand, rand, srandom, israndom
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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: 29.1 $
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## @(#) $Id: randombit,v 29.1 1999/12/14 09:16:04 chongo Exp $
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## @(#) $Source: /usr/local/src/cmd/calc/help/RCS/randombit,v $
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##
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## Under source code control: 1997/02/17 01:18:22
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## File existed as early as: 1997
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##
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## chongo <was here> /\oo/\ http://reality.sgi.com/chongo/
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## Share and enjoy! :-) http://reality.sgi.com/chongo/tech/comp/calc/
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