132 lines
3.3 KiB
C
132 lines
3.3 KiB
C
/*=============================================================================
|
|
|
|
This file is part of FLINT.
|
|
|
|
FLINT 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.
|
|
|
|
FLINT 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 FLINT; if not, write to the Free Software
|
|
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
|
|
|
=============================================================================*/
|
|
/******************************************************************************
|
|
|
|
Copyright (C) 2007, 2008 William Hart
|
|
Copyright (C) 2008 Peter Shrimpton
|
|
Copyright (C) 2010 Fredrik Johansson
|
|
|
|
******************************************************************************/
|
|
|
|
#define ulong ulongxx /* interferes with system includes */
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#undef ulong
|
|
#define ulong mp_limb_t
|
|
#include <gmp.h>
|
|
#include "flint.h"
|
|
#include "ulong_extras.h"
|
|
|
|
unsigned int nextmod30[] =
|
|
{
|
|
1, 6, 5, 4, 3, 2, 1, 4, 3, 2, 1, 2, 1, 4, 3, 2, 1, 2, 1,
|
|
4, 3, 2, 1, 6, 5, 4, 3, 2, 1, 2
|
|
};
|
|
|
|
unsigned int nextindex[] =
|
|
{
|
|
1, 7, 7, 7, 7, 7, 7, 11, 11, 11, 11, 13, 13, 17, 17, 17, 17, 19, 19,
|
|
23, 23, 23, 23, 29, 29, 29, 29, 29, 29, 1
|
|
};
|
|
|
|
#define NEXTPRIME_PRIMES 54
|
|
|
|
|
|
mp_limb_t n_nextprime(mp_limb_t n, int proved)
|
|
{
|
|
mp_limb_t * moduli;
|
|
ulong i, index;
|
|
|
|
if (n < 7)
|
|
{
|
|
if (n < 2)
|
|
return 2;
|
|
n++;
|
|
n |= 1;
|
|
return n;
|
|
}
|
|
|
|
if (n >= UWORD_MAX_PRIME)
|
|
{
|
|
flint_printf("Exception (n_nextprime). No larger single-limb prime exists.\n");
|
|
abort();
|
|
}
|
|
|
|
index = n % 30;
|
|
n += nextmod30[index];
|
|
index = nextindex[index];
|
|
|
|
if (n <= flint_primes_small[NEXTPRIME_PRIMES-1])
|
|
{
|
|
if (n == 7) return 7;
|
|
if (n == 11) return 11;
|
|
if (n == 13) return 13;
|
|
|
|
while (((n % 7) == 0) || ((n % 11) == 0) || ((n % 13) == 0))
|
|
{
|
|
n += nextmod30[index];
|
|
index = nextindex[index];
|
|
}
|
|
return n;
|
|
}
|
|
|
|
moduli = (mp_limb_t *) flint_malloc(NEXTPRIME_PRIMES * sizeof(mp_limb_t));
|
|
|
|
for (i = 3; i < NEXTPRIME_PRIMES; i++)
|
|
moduli[i] = (n % flint_primes_small[i]);
|
|
|
|
while (1)
|
|
{
|
|
ulong composite = 0;
|
|
ulong diff, acc, pr;
|
|
|
|
diff = nextmod30[index];
|
|
|
|
/* First check residues */
|
|
for (i = 3; i < NEXTPRIME_PRIMES; i++)
|
|
{
|
|
composite |= (moduli[i] == 0);
|
|
acc = moduli[i] + diff;
|
|
pr = flint_primes_small[i];
|
|
moduli[i] = acc >= pr ? acc - pr : acc;
|
|
}
|
|
|
|
if (composite)
|
|
{
|
|
n += diff;
|
|
index = nextindex[index];
|
|
continue;
|
|
}
|
|
|
|
if ((!proved && n_is_probabprime(n)) || (proved && n_is_prime(n)))
|
|
{
|
|
break;
|
|
}
|
|
else
|
|
{
|
|
n += diff;
|
|
index = nextindex[index];
|
|
}
|
|
}
|
|
|
|
flint_free(moduli);
|
|
return n;
|
|
}
|