Class: Prime
 Inherits:

Object
 Object
 Prime
 Extended by:
 Enumerable, Forwardable
 Includes:
 Enumerable
 Defined in:
 lib/prime.rb
Overview
The set of all prime numbers.
Example
Prime.each(100) do prime
p prime #=> 2, 3, 5, 7, 11, ...., 97
end
Retrieving the instance
Prime.new is obsolete. Now Prime has the default instance and you can access it as Prime.instance.
For convenience, each instance method of Prime.instance can be accessed as a class method of Prime.
e.g.
Prime.instance.prime?(2) #=> true
Prime.prime?(2) #=> true
Generators
A "generator" provides an implementation of enumerating pseudoprime numbers and it remembers the position of enumeration and upper bound. Futhermore, it is a external iterator of prime enumeration which is compatible to an Enumerator.
Prime::PseudoPrimeGenerator is the base class for generators. There are few implementations of generator.
 Prime::EratosthenesGenerator

Uses eratosthenes's sieve.
 Prime::TrialDivisionGenerator

Uses the trial division method.
 Prime::Generator23

Generates all positive integers which is not divided by 2 nor 3. This sequence is very bad as a pseudoprime sequence. But this is faster and uses much less memory than other generators. So, it is suitable for factorizing an integer which is not large but has many prime factors. e.g. for Prime#prime? .