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[Efficiency] optimized jit.unpack, other stuff ?

August 10, 2008 | 12:21 am

Hi,

i’m discovering jitter more deeply since few months, and i’m (like many, i thinks?) always looking for efficiency… And, on my 2,2Ghz MBP, working on 1200*700 4 planes matrixes, i noticed that :

- sending it to some objects like jit.coerce, taking only few microseconds, is very efficient.

- copying it to an other jit.matrix of the same size takes 1 millisecond.

- sending it to [jit.unpack] takes 10 milliseconds…

…And i found that expensive for just unpacking a matrix so i started to compare efficiency of some differents jitter objects… then i found a more efficent way to do the same thing than jit.unpack, using 4 jit.rgb2luma !! (a little bit more efficient if you need all the four planes, but really more efficient if you only need some) (and as each [jit.rgb2luma ...] operate on four planes, i’m sure that there must be a furthermore efficient way to unpack a 4 plane matrix…)

You can see my test patcher down here.

Does anybody have any other interresting topics or test-patchers relating to "efficiency comparisons" of jitter objects ?

Thanks,

Alexandre

– Pasted Max Patch, click to expand. –

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