Class: Neuron

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

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(number_of_inputs, activation_function) ⇒ Neuron

Returns a new instance of Neuron.



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# File 'lib/nn.rb', line 5

def initialize(number_of_inputs, activation_function)
    @initial_weights = Array.new(number_of_inputs) { rand(-1.0..1.0) }
    @initial_bias = rand(-1.0..1.0)

    @weights = @initial_weights.map { |w| Value.new(w) }
    @bias = Value.new(@initial_bias)

    @activation_function = activation_function
end

Instance Attribute Details

#bias ⇒ Object (readonly)

Returns the value of attribute bias.



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# File 'lib/nn.rb', line 29

def bias
  @bias
end

#weights ⇒ Object (readonly)

Returns the value of attribute weights.



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# File 'lib/nn.rb', line 29

def weights
  @weights
end

Instance Method Details

#calc(inputs) ⇒ Object 



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# File 'lib/nn.rb', line 35

def calc(inputs)
    # xw + b
    n = self.weights.size
    raise "Wrong number of inputs! #{inputs.size} expected #{n}" unless n == inputs.size
    sum = self.bias
    n.times do |index|
        sum += self.weights[index] * inputs[index]
    end
    if @activation_function == :tanh
        sum.tanh
    elsif @activation_function == :relu
        sum.relu
    elsif @activation_function == :sigmoid
        sum.sigmoid
    else
        raise "Unsupported activation function: #{activation_function}"
    end
end

#parameters ⇒ Object 



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# File 'lib/nn.rb', line 31

def parameters
    self.weights + [self.bias]
end

#reset_params ⇒ Object 



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# File 'lib/nn.rb', line 15

def reset_params
    @initial_weights.each_with_index do |w,i|
        @weights[i].value = w
    end
    @bias.value = @initial_bias
end

#set_params(params) ⇒ Object 



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# File 'lib/nn.rb', line 22

def set_params(params)
    n = 1 + @weights.size
    raise "Illegal number of parameters: #{params.size} expected #{n}" if n != params.size
    @bias.value = params[0]
    (1...params.size).each { |i| @weights[i - 1].value = params[i] }
end