Numeri primi - Prime numbers
Modulo Python per la gestione di numeri primi. Contiene funzioni per:
- trovare i numeri primi minori di un numero dato;
- trovare il numero primo successivo ad un numero dato;
- determinare se un numero è primo.
http://www.fantascienza.net/leonardo/so/index.html#primes
--------------------
Python module for prime numbers management. It contains functions to:
- find the prime numbers up to a given number;
- to find the prime number successive to a given number;
- to tell if a given number is prime.
http://www.fantascienza.net/leonardo/so/index.html#primes
Python code used to test primeQ function against gmpy (http://gmpy.sourceforge.net/):
import gmpy
from random import randint
for i in xrange(10000):
n = randint(2, 341550071728321)
if gmpy.is_prime(n) != int(primeQ(n)):
print n
Mathematica code used to test nextPrime function against Mathematica:
succPrime[n_] := Block[{m = n + 1},
While[Not[PrimeQ[m]], m++ ];
m]
data = ReadList["c:\\datas\\data", Number];
succ = ReadList["c:\\datas\\succ", Number];
For[i = 1, i <= 45006, i++,
If[Mod[i, 500] == 0, Print["*"]];
If[
succPrime[ data[[i]] ] != succ[[i]],
Print[i]
]
]
Python code used to generate the data numbers loaded by the Mathematica code:
from random import randint, seed
seed(1)
thresholds = (1373653, 25326001, 3215031751, 118670087467,
2152302898747, 3474749660383, 341550071728321)
testdata = list(thresholds[:-1])
last = thresholds[-1]
testdata.extend( randint(0, last) for x in xrange(10000) )
for n in thresholds[:-1]:
inf = int(n * 0.9)
sup = int(n * 1.1)
testdata.extend( randint(inf, sup) for x in xrange(5000) )
inf = int(thresholds[-1] * 0.9)
sup = thresholds[-1]
testdata.extend( randint(inf, sup) for x in xrange(5000) )
print "Numbers saved:", len(testdata)
file("data", "w").write( "\n".join(map(str, testdata)) )
Some similar code was used to test primeQ function against nextPrime.
Python code used to write the "succ" file of prime numbers successive to the numbers contained in the "data" file:
numbers = map(int, file("data"))
print "Numbers:", len(numbers)
succ = []
for i, n in enumerate(numbers):
if i % 500 == 0: print i
succ.append( nextPrime(n))
file("succ", "w").write( "\n".join(map(str, succ)) )
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leonardo_m) wrote,
