Fast Fourier transform: Difference between revisions
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<lang julia>]add FFTW |
<lang julia>]add FFTW |
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using FFTW</lang> |
using FFTW</lang> |
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<lang julia> |
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function fft(a) |
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y1 = Any[]; y2 = Any[] |
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n = length(a) |
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if n ==1 return a end |
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wn(n) = exp(-2*π*im/n) |
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y_even = fft(a[1:2:end]) |
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y_odd = fft(a[2:2:end]) |
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w = 1 |
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for k in 1:Int(n/2) |
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push!(y1, y_even[k] + w*y_odd[k]) |
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push!(y2, y_even[k] - w*y_odd[k]) |
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w = w*wn(n) |
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end |
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return vcat(y1,y2) |
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end |
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</julia> |
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=={{header|Kotlin}}== |
=={{header|Kotlin}}== |
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