54 lines
1.6 KiB
C++
54 lines
1.6 KiB
C++
/* -*- c++ -*- ----------------------------------------------------------
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LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
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http://lammps.sandia.gov, Sandia National Laboratories
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Steve Plimpton, sjplimp@sandia.gov
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Copyright (2003) Sandia Corporation. Under the terms of Contract
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DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
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certain rights in this software. This software is distributed under
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the GNU General Public License.
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See the README file in the top-level LAMMPS directory.
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------------------------------------------------------------------------- */
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#ifndef LMP_RANDOM_MT_H
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#define LMP_RANDOM_MT_H
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#include "pointers.h"
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namespace LAMMPS_NS {
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class RanMT : protected Pointers {
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public:
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RanMT(class LAMMPS *, int);
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virtual ~RanMT();
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double uniform();
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double gaussian();
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double gaussian_z();
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private:
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// some internal constants
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enum {MT_S=7,MT_U=11,MT_T=15,MT_L=18,MT_R=31,MT_M=397,MT_N=624};
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uint32_t _m[MT_N]; // state of RNG
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int _idx; // twist index
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int _save; // for gaussian distributed RNG
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int _nlayers; // number of layers for ziggurat method
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double *_xlayers, *_ylayers; // layer distribution for ziggurat method
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double _second; // stored RNG for gaussian distributed RNG
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uint32_t _randomize(); // generate new 32-bit integer
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};
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}
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#endif
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/* ERROR/WARNING messages:
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E: Invalid seed for Marsaglia random # generator
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The initial seed for this random number generator must be a positive
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integer less than or equal to 900 million.
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*/
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