[Efficiency] optimized jit.unpack, other stuff ?


    Aug 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