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/* List and count primes.
Copyright 2000 Free Software Foundation, Inc.
This program 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.
This program 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
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place - Suite 330, Boston, MA 02111-1307, USA. */
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "gmp.h"
/* Sieve table size */
#define ST_SIZE 50000
/* Largest prime to sieve with */
#define MAX_S_PRIME 32000
main (int argc, char **argv)
{
char *progname = argv[0];
mpz_t r0, r1; /* range */
mpz_t cur;
mpz_t max_s_prime_squared;
unsigned char *st;
unsigned long i, ii;
unsigned long nprimes = 0;
unsigned long last;
int flag_print = 1;
int flag_count = 0;
st = malloc (ST_SIZE);
while (argc != 1)
{
if (strcmp (argv[1], "-c") == 0)
{
flag_count = 1;
argv++;
argc--;
}
else if (strcmp (argv[1], "-p") == 0)
{
flag_print = 2;
argv++;
argc--;
}
else
break;
}
if (flag_count)
flag_print--; /* clear unless an explicit -p */
mpz_init (r0);
mpz_init (r1);
mpz_init (cur);
mpz_init_set_ui (max_s_prime_squared, MAX_S_PRIME);
mpz_mul_ui (max_s_prime_squared, max_s_prime_squared, MAX_S_PRIME);
if (argc == 2)
{
mpz_set_ui (r0, 2);
mpz_set_str (r1, argv[1], 0);
}
else if (argc == 3)
{
mpz_set_str (r0, argv[1], 0);
if (argv[2][0] == '+')
{
mpz_set_str (r1, argv[2] + 1, 0);
mpz_add (r1, r1, r0);
}
else
mpz_set_str (r1, argv[2], 0);
}
else
{
fprintf (stderr, "usage: %s [-c] [-g] [from [+]]to\n", progname);
exit (1);
}
if (mpz_cmp_ui (r0, 2) < 0)
mpz_set_ui (r0, 2);
if ((mpz_get_ui (r0) & 1) == 0)
{
if (mpz_cmp_ui (r0, 2) == 0)
{
if (flag_print)
puts ("2");
nprimes++;
}
mpz_add_ui (r0, r0, 1);
}
mpz_set (cur, r0);
while (mpz_cmp (cur, r1) <= 0)
{
memset (st, 1, ST_SIZE);
for (i = 3; i < MAX_S_PRIME; i += 2)
{
unsigned long start;
start = mpz_tdiv_ui (cur, i);
if (start != 0)
start = i - start;
if (mpz_cmp_ui (cur, i - start) == 0)
start += i;
for (ii = start; ii < ST_SIZE; ii += i)
st[ii] = 0;
}
last = 0;
for (ii = 0; ii < ST_SIZE; ii += 2)
{
if (st[ii] != 0)
{
mpz_add_ui (cur, cur, ii - last);
last = ii;
if (mpz_cmp (cur, r1) > 0)
goto done;
/* Perform probabilistic prime test, but only if we're in a range
were the sieving hasn't already proved this number prime. */
if (mpz_cmp (cur, max_s_prime_squared) < 0
|| mpz_probab_prime_p (cur, 3))
{
nprimes++;
if (flag_print)
{
mpz_out_str (stdout, 10, cur); puts ("");
}
}
}
}
mpz_add_ui (cur, cur, ST_SIZE - last);
}
done:
if (flag_count)
printf ("Pi(interval) = %lu\n", nprimes);
exit (0);
}
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