17 lines
495 B
Plaintext
17 lines
495 B
Plaintext
func fft(arr) {
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arr.len == 1 && return arr
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var evn = fft([arr[^arr -> grep { .is_even }]])
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var odd = fft([arr[^arr -> grep { .is_odd }]])
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var twd = (Num.tau.i / arr.len)
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^odd -> map {|n| odd[n] *= ::exp(twd * n)}
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(evn »+« odd) + (evn »-« odd)
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}
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var cycles = 3
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var sequence = 0..15
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var wave = sequence.map {|n| ::sin(n * Num.tau / sequence.len * cycles) }
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say "wave:#{wave.map{|w| '%6.3f' % w }.join(' ')}"
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say "fft: #{fft(wave).map { '%6.3f' % .abs }.join(' ')}"
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