cyprimes 0.5.0

Module for working with prime numbers.

CyPrimes

Module for working with prime numbers written in Cython.

This is just a toy project to try out Cython.

Installation

# pip install cyprimes

To install CyPrimes a C-compiler (GCC, MinGW) is required.

Usage

Function is_prime(number)

This function returns True if the number is prime. Because it uses the C-type unsigned long for number it raises a ValueError if number < 0 or number > cyprimes.max_ulong. It raises a TypeError if number is not an integer.

Class Primes(limit)

This class uses the Sieve of Eratosthenes to find all prime numbers up to limit.

An instance of this class supports the len function, the in operator, subscription (with integer indexes and slices), is iterable, and can be pickled. It raises a TypeError if limit is not an integer.

Methods: All methods raise TypeErrors if their parameters are not integers and ValueErrors if they are out of range.

• index(number): Returns the index of number. Raises ValueError if number is not prime.

• next(number): Returns the next prime number after number or None if their is none in the given range.

• previous(number): Returns the previous prime number before number or None if their is none in the given range.

• between(start, end): Returns a tuple with all prime numbers in the closed interval [start, end].

Warning

Although this class uses a bitarray for the sieve be carefull not run out of memory:

limit	size
100	7 B
1 000	63 B
10 000	625 B
100 000	6 KiB
1 000 000	61 KiB
10 000 000	610 KiB
100 000 000	6 MiB
1 000 000 000	60 MiB
10 000 000 000	596 MiB
100 000 000 000	6 GiB
1 000 000 000 000	58 GiB

History

2020-06-02 (0.4.0)

• First public release

2020-06-03 (0.4.1)

• Fix: Primes() and is_prime() now raise TypeErrors if the parameter is not an integer
• Fix: Primes.__reversed__() now works correct

2020-06-03 (0.4.2)

• Fix: README

2020-06-03 (0.4.3)

• Fix: README again :blush:

2020-06-15 (0.5.0)

• Add methods next(), previous(), and between() to class Primes
• Add tests