75 lines
2.2 KiB
C++
75 lines
2.2 KiB
C++
// This may look like C code, but it is really -*- C++ -*-
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/*
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Copyright (C) 1988 Free Software Foundation
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written by Dirk Grunwald (grunwald@cs.uiuc.edu)
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This file is part of GNU CC.
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GNU CC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY. No author or distributor
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accepts responsibility to anyone for the consequences of using it
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or for whether it serves any particular purpose or works at all,
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unless he says so in writing. Refer to the GNU CC General Public
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License for full details.
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Everyone is granted permission to copy, modify and redistribute
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GNU CC, but only under the conditions described in the
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GNU CC General Public License. A copy of this license is
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supposed to have been given to you along with GNU CC so you
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can know your rights and responsibilities. It should be in a
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file named COPYING. Among other things, the copyright notice
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and this notice must be preserved on all copies.
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*/
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#ifndef _ACG_h
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#define _ACG_h 1
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#include <RNG.h>
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#include <math.h>
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#ifdef __GNUG__
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#pragma once
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#pragma interface
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#endif
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//
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// Additive number generator. This method is presented in Volume II
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// of The Art of Computer Programming by Knuth. I've coded the algorithm
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// and have added the extensions by Andres Nowatzyk of CMU to randomize
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// the result of algorithm M a bit by using an LCG & a spatial
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// permutation table.
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//
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// The version presented uses the same constants for the LCG that Andres
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// uses (chosen by trial & error). The spatial permutation table is
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// the same size (it's based on word size). This is for 32-bit words.
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//
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// The ``auxillary table'' used by the LCG table varies in size, and
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// is chosen to be the the smallest power of two which is larger than
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// twice the size of the state table.
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//
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class ACG : public RNG {
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unsigned long initialSeed; // used to reset generator
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int initialTableEntry;
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unsigned long *state;
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unsigned long *auxState;
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short stateSize;
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short auxSize;
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unsigned long lcgRecurr;
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short j;
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short k;
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protected:
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public:
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ACG(unsigned long seed = 0, int size = 55);
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virtual ~ACG();
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//
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// Return a long-words word of random bits
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//
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virtual unsigned long asLong();
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virtual void reset();
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};
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#endif
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