Module: DSP::Autocorrelation

Defined in:
lib/dsprb/autocorrelation.rb,
sig/dsprb.rbs

Class Method Summary collapse

Class Method Details

.call(frame, order) ⇒ ::Array[::Float]

Unbiased-denominator-free autocorrelation r = sum_i x x[i + k], k = 0..order.

Parameters:

  • (frame)
  • (::Integer)

Returns:

  • (::Array[::Float])

Raises:

  • (ArgumentError) 


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# File 'lib/dsprb/autocorrelation.rb', line 8

def call(frame, order)
  raise ArgumentError, "order must be non-negative, got #{order}" if order.negative?

  length = frame.length

  Array.new(order + 1) do |lag|
    total = 0.0
    index = 0
    limit = length - lag
    while index < limit
      total += frame[index] * frame[index + lag]
      index += 1
    end

    total
  end
end