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One method of improving efficiency further in some cases is the Frobenius pseudoprimality test; a round of this test takes about three times as long as a round of Miller–Rabin, but achieves a probability bound comparable to seven rounds of Miller–Rabin. The Frobenius test is a generalization of the Lucas probable prime test.
In Python, the NZMATH [23] library has the strong pseudoprime and Lucas tests, but does not have a combined function. The SymPy [ 24 ] library does implement this. As of 6.2.0, GNU Multiple Precision Arithmetic Library 's mpz_probab_prime_p function uses a strong Lucas test and a Miller–Rabin test; previous versions did not make use of ...
The isPrime function was inaccurate, as range doesn't include the higher end, so e.g. if checking for primality of 9, it would try numbers from 2 to 2, and conclude it was prime. I've added 1 to the upper end of the range so that the isPrime function works, in case anyone else comes along and tries to use it.
The oldest known method for generating a list of primes is called the sieve of Eratosthenes. [127] The animation shows an optimized variant of this method. [128] Another more asymptotically efficient sieving method for the same problem is the sieve of Atkin. [129] In advanced mathematics, sieve theory applies similar methods to other problems ...
A prime sieve or prime number sieve is a fast type of algorithm for finding primes. There are many prime sieves. The simple sieve of Eratosthenes (250s BCE), the sieve of Sundaram (1934), the still faster but more complicated sieve of Atkin [1] (2003), sieve of Pritchard (1979), and various wheel sieves [2] are most common.
The Miller–Rabin primality test or Rabin–Miller primality test is a probabilistic primality test: an algorithm which determines whether a given number is likely to be prime, similar to the Fermat primality test and the Solovay–Strassen primality test.
While Carmichael numbers are substantially rarer than prime numbers (Erdös' upper bound for the number of Carmichael numbers [3] is lower than the prime number function n/log(n)) there are enough of them that Fermat's primality test is not often used in the above form.
In mathematics, the prime-counting function is the function counting the number of prime numbers less than or equal to some real number x. [1] [2] It is denoted by π(x) (unrelated to the number π). A symmetric variant seen sometimes is π 0 (x), which is equal to π(x) − 1 ⁄ 2 if x is exactly a prime number, and equal to π(x) otherwise.