DSP Robotics Support

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def fft doinverse = true
      src = self
      # raise ArgumentError.new "Expected array input but was '#{src.class}'" unless src.kind_of? Array
      n = src.length
      nlog2 = Math.log( n ) / Math.log( 2 )
      raise ArgumentError.new "Input array size must be a power of two but was '#{n}'" unless nlog2.floor - nlog2 == 0.0
      n2 = n / 2
      phi = Math::PI / n2
      if doinverse
         phi = -phi
      else
         src.collect!{|c| c /= n.to_f}
      end

      # build a sine/cosine table
      wt = Array.new n2
      wt.each_index { |i| wt[i] = Complex(Math.cos(i * phi), Math.sin(i * phi)) } ???Is this building 2 dimensional array?

      # bit reordering ?? What is this doing?
      n1 = n - 1
      j = 0
      1.upto(n1) do |i|
         m = n2
         while j >= m
            j -= m
            m /= 2
         end
         j += m
         src[i],src[j] = src[j],src[i] if j > i
      end

      # 1d(N) Ueberlagerungen ???
      mm = 1
      begin
         m = mm
         mm *= 2
         0.upto(m - 1) do |k|
            w = wt[ k * n2 ]
            k.step(n1, mm) do |i|
               j = i + m
               src[j] = src[i] - (temp = w * src[j])
               src[i] += temp
            end
         end
         n2 /= 2
      end while mm != n
      src
   end
end

//usage
real = []
imag = []

@in.fft(false).each {|i| real.push i.real; imag.push i.imag}
output 0, real; output 1, imag

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a = Complex(1, 0.53)
b = a.real # = 1
c = a.imag # = 0.53

Code: Select all

    //usage
    real = []
    imag = []

    @in.fft(false).each {|i| real.push i.real; imag.push i.imag}
    output 0, real; output 1, imag