Class: Binomial

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

Instance Method Summary collapse

Constructor Details

#initialize(n: nil, p: nil, tries: nil, probability: nil, failure: nil) ⇒ Binomial

Note:

if no probability is defined, the default value will be 0.5

 @param failure [Float] alias for ‘p = 1 - failure`

Parameters:

  • n (Fixnum) (defaults to: nil) —

    number of tries

  • p (Float) (defaults to: nil) —

    probability of success

  • tries (Fixnum) (defaults to: nil) —

    alias for n

  • probability (Float) (defaults to: nil) —

    alias for p

Raises:

  • (ArgumentError) 


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# File 'lib/binomial_distribution.rb', line 38

def initialize n: nil, p: nil, tries: nil, probability: nil, failure: nil
  tries_count = n || tries
  probability = p || probability || (failure && 1.0 - failure) || 0.5
  raise ArgumentError, "The argument `n` `#{tries_count}` is not an Integer" unless tries_count.is_a? Integer
  raise ArgumentError, "The argument `p` `#{probability}` is not a Numeric" unless probability.is_a? Numeric
  tries_count = Float(tries_count)
  raise Math::DomainError, "The argument `n` `#{tries_count}` is not in greater or equal to 0" if tries_count < 0.0
  raise Math::DomainError, "The argument `p` `#{probability}` is not in greater or equal to 0" if probability < 0.0
  raise Math::DomainError, "The argument `p` `#{probability}` is not in lesser or equal to 1" if probability > 1.0
  @n = tries_count.to_i
  @p = probability.to_f
end

Instance Method Details

#distribute(k) ⇒ Float

Returns probability.

Parameters:

  • k (Fixnum) —

    number of test successful.

  • k (Enumerable) —

    list of number of test successful.

Returns:

  • (Float) —

    probability



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# File 'lib/binomial_distribution.rb', line 58

def distribute k
  if k.is_a? Enumerable
    distribute_enumerable k
  elsif k.is_a? Integer
    distribute_integer k
  else
    raise ArgumentError
  end
end

#to_s ⇒ Object 



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# File 'lib/binomial_distribution.rb', line 51

def to_s
  "#<#{self.class} @n=#@n, @p=#@p>"
end