Class: Prime::Generator23

Inherits:
PseudoPrimeGenerator show all
Defined in:
lib/prime.rb

Overview

Generates all integers which are greater than 2 and are not divisible by either 2 or 3.

This is a pseudo-prime generator, suitable on checking primality of an integer by brute force method.

Instance Method Summary collapse

Methods inherited from PseudoPrimeGenerator

#each, #size, #upper_bound, #upper_bound=, #with_index, #with_object

Constructor Details

#initialize ⇒ Generator23

Returns a new instance of Generator23.



352
353
354
355
356
 
# File 'lib/prime.rb', line 352

def initialize
  @prime = 1
  @step = nil
  super
end

Instance Method Details

#rewind ⇒ Object 



372
373
374
 
# File 'lib/prime.rb', line 372

def rewind
  initialize
end

#succ ⇒ Object Also known as: next 



358
359
360
361
362
363
364
365
366
367
368
369
370
 
# File 'lib/prime.rb', line 358

def succ
  if (@step)
    @prime += @step
    @step = 6 - @step
  else
    case @prime
    when 1; @prime = 2
    when 2; @prime = 3
    when 3; @prime = 5; @step = 2
    end
  end
  @prime
end