Appendix B         Daisy code for FFT--decimation in frequency


fft = ^\[x lgsize]. rec:[
	ffdo
	\[x wtree lgsize]. if:<
		zero?:lgsize x
		    shuffle:
		    <ffdo		*			 >:<
		    <vec+vec:x		vecXvec:<wtree vec-vec:x>>
		    <0:deal:wtree	*			 >
		    <dcr:lgsize		*			 > >
		>
	ffdo:<x buildAtree:dcr:lgsize lgsize>	] 

shuffle = ^\pair. if:<
		Scalar?:0:pair pair
		<shuffle*>:pair >