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math.transforms.fft: hah, once-power-of-2, always-power-of-2.

db4
John Benediktsson 2014-06-04 12:28:59 -07:00
parent d2c6bc41ce
commit 7bde6a53da
1 changed files with 3 additions and 3 deletions
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extra/math/transforms/fft/fft.factor
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@ -21,8 +21,8 @@ DEFER: (fft)
:: (fast-fft) ( seq inverse? -- seq' ) :: (fast-fft) ( seq inverse? -- seq' )
seq length :> N seq length :> N
N 1 = [ seq ] [ N 1 = [ seq ] [
seq even-indices inverse? (fft) seq even-indices inverse? (fast-fft)
seq odd-indices inverse? (fft) seq odd-indices inverse? (fast-fft)
inverse? 1 -1 ? 2pi * N / inverse? 1 -1 ? 2pi * N /
[ * cis * ] curry map-index! [ * cis * ] curry map-index!
[ [ + inverse? [ 2 / ] when ] 2map ] [ [ + inverse? [ 2 / ] when ] 2map ]
@ -32,7 +32,7 @@ DEFER: (fft)
: (fft) ( seq inverse? -- seq' ) : (fft) ( seq inverse? -- seq' )
over length power-of-2? over length power-of-2?
[ (fast-fft) ] [ (slow-fft) ] if ; inline recursive [ (fast-fft) ] [ (slow-fft) ] if ; inline
PRIVATE> PRIVATE>