Thresholding then proceeds by initializing the vector block and coefficient indices and then computing the vector length as {TAIL ~ the square root} of {HEAD ~ the sum} of squares of the vectors component values  
Thresholding then proceeds by initializing the vector block and coefficient indices and then computing the vector length as { TAIL ~ the square root } of { HEAD ~ the sum } of squares of the vectors component values
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH