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Array handling

Scheduled Pinned Locked Moved .NET (Core and Framework)
csharpquestioncssdata-structures
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  • S sarabjs

    Great find! I've made the changes you'd suggested in my algorithm (to avoid repeatedly summing up columns in overlapping windows), and have been able to shed over 1 second! The release mode however is still not giving much improvement. The 'optimize' flag is true and 'check for arithmetic overflow' and 'generate debug info' are both set to false. I must mention that the code I had posted is only a small section of my entire procedure. On my end, I'm processing the input image through a series of functions(/filters), each of which update pixel values depending upon the environments and are similar to the extract in my previous post. Currently, the entire procedure takes an average of ~ 2.4 seconds for a set of 14 test pictures in both Debug and Release modes. Also, am only working with integers. The input images are 8-bit grayscale images, so these integers are only between 0 and 255. Thanks...

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    Robert Rohde
    wrote on last edited by
    #21

    So you are now relatively close to your goal... You say you are working on images. Where does the data come from? Do you convert a Bitmap into a matrix, do your calculations and then recreate the image? If yes you could instead work directly (unsafe) on the bitmap data with the LockBits function from the Bitmap. Its a bit complicated (I don't like pointer handling) but its worth the try.

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    • R Robert Rohde

      So you are now relatively close to your goal... You say you are working on images. Where does the data come from? Do you convert a Bitmap into a matrix, do your calculations and then recreate the image? If yes you could instead work directly (unsafe) on the bitmap data with the LockBits function from the Bitmap. Its a bit complicated (I don't like pointer handling) but its worth the try.

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      sarabjs
      wrote on last edited by
      #22

      I pick the data from the image using the BitmapData object, copy all pixel values to the 2-dimensional array, process this array and finally copy the values back to the memory recreating the image. I don't have much experience with pointers either :sigh:, and am avoiding using them extensively 'cause the using the bitmap data directly seems more complicated since the pixels are placed linearly in the memory - whereas I need to analyze 2-dimensional windows (hence the more suitable pixel map). Besides, I'm not even sure whether using unsafe code and pointers will provide a major breakthrough (although even a not so major breakthrough is acceptable for my case), since most of my processing comprises simple mathematical operations.

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      • S sarabjs

        I pick the data from the image using the BitmapData object, copy all pixel values to the 2-dimensional array, process this array and finally copy the values back to the memory recreating the image. I don't have much experience with pointers either :sigh:, and am avoiding using them extensively 'cause the using the bitmap data directly seems more complicated since the pixels are placed linearly in the memory - whereas I need to analyze 2-dimensional windows (hence the more suitable pixel map). Besides, I'm not even sure whether using unsafe code and pointers will provide a major breakthrough (although even a not so major breakthrough is acceptable for my case), since most of my processing comprises simple mathematical operations.

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        Robert Rohde
        wrote on last edited by
        #23

        You are probably right. Probably optimization ends here... :(( Btw: What kind of machine is this running on? Multiprocessor? Hyperthreading? I have have some multithreaded improvements in mind :-D

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        • R Robert Rohde

          You are probably right. Probably optimization ends here... :(( Btw: What kind of machine is this running on? Multiprocessor? Hyperthreading? I have have some multithreaded improvements in mind :-D

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          sarabjs
          wrote on last edited by
          #24

          Single Processor, Single Thread! Let's hear about the improvements...

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          • S sarabjs

            Single Processor, Single Thread! Let's hear about the improvements...

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            Robert Rohde
            wrote on last edited by
            #25

            sarabjs wrote: Single Processor, Single Thread! I think in that case threading would be contraproductive... Sorry but I think I have no further suggestions for improving the performance :((

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            • R Robert Rohde

              sarabjs wrote: Single Processor, Single Thread! I think in that case threading would be contraproductive... Sorry but I think I have no further suggestions for improving the performance :((

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              sarabjs
              wrote on last edited by
              #26

              Nein problemo! :) You've done great.. Thanks for the help... Sarab.

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