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random.cc
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random.cc
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// random.cc: implementation of random functions used in smat testing
//////////////////////////////////////////////////////////////////////////
//
// Copyright 1990-2012 John Cremona
//
// This file is part of the eclib package.
//
// eclib is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the
// Free Software Foundation; either version 2 of the License, or (at your
// option) any later version.
//
// eclib is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License
// along with eclib; if not, write to the Free Software Foundation,
// Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
//
//////////////////////////////////////////////////////////////////////////
/* codes were copied from the book
* Numerical recipes in C,
* under "immediate license" agreement,
* ( see page xvi of the second edition ).
*/
#define IA 16807
#define IM 2147483647
#define AM (1.0/IM)
#define IQ 127773
#define IR 2836
#define MASK 123459876
float ran0( long& idum )
{
long k;
float ans;
idum ^= MASK;
k = (idum)/IQ;
idum = IA*(idum - k*IQ) - IR*k;
if( idum < 0 ) idum += IM;
ans = AM*(idum);
idum ^= MASK;
return ans;
}
float ran0( int& idum )
{
int k;
float ans;
idum ^= MASK;
k = (idum)/IQ;
idum = IA*(idum - k*IQ) - IR*k;
if( idum < 0 ) idum += IM;
ans = AM*(idum);
idum ^= MASK;
return ans;
}