69 lines
2.1 KiB
C++
69 lines
2.1 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 the GNU C++ Library. This library is free
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software; you can redistribute it and/or modify it under the terms of
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the GNU Library General Public License as published by the Free
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Software Foundation; either version 2 of the License, or (at your
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option) any later version. This library is distributed in the hope
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that it will be useful, but WITHOUT ANY WARRANTY; without even the
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implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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PURPOSE. See the GNU Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with this library; if not, write to the Free Software
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Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
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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 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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_G_uint32_t initialSeed; // used to reset generator
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int initialTableEntry;
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_G_uint32_t *state;
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_G_uint32_t *auxState;
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short stateSize;
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short auxSize;
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_G_uint32_t 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(_G_uint32_t 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 _G_uint32_t asLong();
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virtual void reset();
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};
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#endif
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