binary - Julia: Base function 10,000x quicker then similar function -


i'm playing around decimal binary converter 'bin()' in julia, wanting improve performance. need use bigints problem, , calling bin() bigint within file outputs correct binary representation; however, calling function similar bin() function costs minute in time, while bin() takes .003 seconds. why there huge difference?

function binbase(x::unsigned, pad::int, neg::bool)     = neg + max(pad,sizeof(x)<<3-leading_zeros(x))     = array(uint8,i)     while > neg         a[i] = '0'+(x&0x1)         x >>= 1         -= 1     end     if neg; a[1]='-'; end     asciistring(a) end    function bin1(x::bigint, pad::int)     y = bin(x) end    function bin2(x::bigint, pad::int,a::array{uint8,1}, neg::bool)     while pad > neg         a[pad] = '0'+(x&0x1)         x >>= 1         pad -= 1     end     if neg; a[1]='-'; end     asciistring(a) end     function test()     = array(uint8,1000001)     x::bigint= 2     x = (x^1000000)       @time bin1(x,1000001)     @time bin2(x,1000001,a,true)  end  test()

as noted felipe lema, base delegates bigint printing gmp, can print bigints without doing intermediate computations them – doing lots of computations bigints figure out digits quite slow , ends allocating lot of memory. bottom line: doing x >>= 1 extremely efficient things int64 values not efficient things bigints.


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