# File lib/ai4r/neural_network/backpropagation.rb, line 117
      def initialize(network_structure)
        @structure = network_structure
        @initial_weight_function = lambda { |n, i, j| ((rand 2000)/1000.0) - 1}
        @propagation_function = lambda { |x| 1/(1+Math.exp(-1*(x))) } #lambda { |x| Math.tanh(x) }
        @derivative_propagation_function = lambda { |y| y*(1-y) } #lambda { |y| 1.0 - y**2 }
        @disable_bias = false
        @learning_rate = 0.25
        @momentum = 0.1
      end