Assume that multiplication is an expensive operation. Consider the problem of computing squares of succesive integers.
for i := 0 to 99 do x[i] := i*i;versus
next := 0; delta := 1; for i := 0 to 99 do begin x[i] := next; next := next + delta; delta := delta + 2 end;The second version has more code, but does no multiplication.
This form of computation has a long history; it was the basis of Babbage's Difference Engine.
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