/usr/include/linbox/randiter/random-fftprime.h is in liblinbox-dev 1.1.6~rc0-4.1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 | /* -*- mode: C++; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* linbox/algorithms/
* Copyright (C) 2005 Pascal Giorgi
*
* Written by Pascal Giorgi <pgiorgi@uwaterloo.ca>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#ifndef __RANDOM_FFTPRIME_H__
#define __RANDOM_FFTPRIME_H__
#include <linbox/integer.h>
#include <linbox/util/timer.h>
namespace LinBox {
class RandomFFTPrime {
public:
int _bits;
RandomFFTPrime(int bits = 20, unsigned long seed = 0)
: _bits(bits)
{
if (! seed)
RandomFFTPrime::setSeed( BaseTimer::seed() );
else
RandomFFTPrime::setSeed( seed );
}
// define the prime type
typedef integer Prime_Type;
/** @brief randomPrime()
* return a random prime
*/
inline Prime_Type randomPrime() const {
integer tmp;
size_t cbits=5;
size_t tresh;
do {
tresh = 1<<(cbits);
size_t p = 1<<(_bits-cbits);
do {
integer::random(tmp,cbits);
tmp = tmp*p+1;
tresh--;
} while ((::probab_prime(tmp)<2) && (tresh));
cbits++;
}
while(tresh==0);
return tmp;
}
/** @brief randomPrime(Prime_Type& p)
* return a random prime
*/
inline Prime_Type randomPrime (Prime_Type& t) const {
size_t cbits=5;
size_t tresh;
do {
tresh = 1<<(cbits);
size_t p = 1<<(_bits-cbits);
do {
integer::random(t,cbits);
t = t*p+1;
tresh--;
} while (!::probab_prime(t) && (tresh));
cbits++;
}
while(tresh==0);
return t;
}
/** @brief setSeed (unsigned long ul)
* Set the random seed to be ul.
*/
void static setSeed(unsigned long ul) {
integer::seeding(ul);
}
};
}
#endif
|