8 lines
218 B
APL
8 lines
218 B
APL
fft←{
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1>k←2÷⍨N←⍴⍵:⍵
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0≠1|2⍟N:'Argument must be a power of 2 in length'
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even←∇(N⍴0 1)/⍵
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odd←∇(N⍴1 0)/⍵
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T←even×*(0J¯2×(○1)×(¯1+⍳k)÷N)
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(odd+T),odd-T
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}
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