For audio decoding, the butterfly unit determines combinations of components of {HEAD ~ a frequency domain vector} to reduce the number of multiplies required to transform to {TAIL ~ the time domain}  
For audio decoding , the butterfly unit determines combinations of components of { HEAD ~ a frequency domain vector } to reduce the number of multiplies required to transform to { TAIL ~ the time domain }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH