Anonymous user
Fast Fourier transform: Difference between revisions
no edit summary
No edit summary |
|||
Line 2,722:
0.000000000000+0.000000000000I
0.999999999999+2.414213562373I</pre>
=={{header|PowerShell}}==
<lang PowerShell>Function FFT($Arr){
$Len = $Arr.Count
If($Len -le 1){Return $Arr}
$Len_Over_2 = [Math]::Floor(($Len/2))
$Output = New-Object System.Numerics.Complex[] $Len
$EvenArr = @()
$OddArr = @()
For($i = 0; $i -lt $Len; $i++){
If($i % 2){
$OddArr+=$Arr[$i]
}Else{
$EvenArr+=$Arr[$i]
}
}
$Even = FFT($EvenArr)
$Odd = FFT($OddArr)
For($i = 0; $i -lt $Len_Over_2; $i++){
$Twiddle = [System.Numerics.Complex]::Exp([System.Numerics.Complex]::ImaginaryOne*[Math]::Pi*($i*-2/$Len))*$Odd[$i]
$Output[$i] = $Even[$i] + $Twiddle
$Output[$i+$Len_Over_2] = $Even[$i] - $Twiddle
}
Return $Output
}
</lang>
{{out}}
<pre>Real Imaginary Magnitude Phase
---- --------- --------- -----
4 0 4 0
1 -2.41421356237309 2.61312592975275 -1.17809724509617
0 0 0 0
1 -0.414213562373095 1.08239220029239 -0.392699081698724
0 0 0 0
1 0.414213562373095 1.08239220029239 0.392699081698724
0 0 0 0
1 2.41421356237309 2.61312592975275 1.17809724509617</pre>
=={{header|Prolog}}==
| |||