Class: FsrsRuby::Alea

Inherits:
Object
  • Object
show all
Defined in:
lib/fsrs_ruby/alea.rb

Overview

Alea PRNG class

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(seed = nil) ⇒ Alea

Returns a new instance of Alea.



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# File 'lib/fsrs_ruby/alea.rb', line 34

def initialize(seed = nil)
  mash = Mash.new
  @c = 1
  @s0 = mash.call(' ')
  @s1 = mash.call(' ')
  @s2 = mash.call(' ')

  seed = Time.now.to_i if seed.nil?

  @s0 -= mash.call(seed)
  @s0 += 1 if @s0 < 0

  @s1 -= mash.call(seed)
  @s1 += 1 if @s1 < 0

  @s2 -= mash.call(seed)
  @s2 += 1 if @s2 < 0
end

Instance Attribute Details

#c ⇒ Object

Returns the value of attribute c.



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# File 'lib/fsrs_ruby/alea.rb', line 32

def c
  @c
end

#s0 ⇒ Object

Returns the value of attribute s0.



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# File 'lib/fsrs_ruby/alea.rb', line 32

def s0
  @s0
end

#s1 ⇒ Object

Returns the value of attribute s1.



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# File 'lib/fsrs_ruby/alea.rb', line 32

def s1
  @s1
end

#s2 ⇒ Object

Returns the value of attribute s2.



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# File 'lib/fsrs_ruby/alea.rb', line 32

def s2
  @s2
end

Instance Method Details

#next ⇒ Object 



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# File 'lib/fsrs_ruby/alea.rb', line 53

def next
  t = 2091639 * @s0 + @c * 2.3283064365386963e-10  # 2^-32
  @s0 = @s1
  @s1 = @s2
  @c = t.to_i
  @s2 = t - @c
  @s2
end

#state ⇒ Object 



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# File 'lib/fsrs_ruby/alea.rb', line 62

def state
  { c: @c, s0: @s0, s1: @s1, s2: @s2 }
end

#state=(new_state) ⇒ Object 



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# File 'lib/fsrs_ruby/alea.rb', line 66

def state=(new_state)
  @c = new_state[:c]
  @s0 = new_state[:s0]
  @s1 = new_state[:s1]
  @s2 = new_state[:s2]
end