in reply to Graph a file without using arrays

It is pretty easy to create a graph yourself using GDs drawing primitives, as you read the file, though you would need to make two passes through the file. The first to calculate minimums & maximums so you know how to scale the data.

But still the problem remains. If there are so many values that loading them into ram is a problem, then plotting them all on a single graph will either result in graph so dense it is unreadable, or so large that the image size itself could be a memory problem.

Without you saying

There's really not a lot anyone can do to help.

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Re^2: Graph a file without using arrays
by ITmajor (Beadle) on Sep 22, 2008 at 18:57 UTC
    In response to Grandfather and BrowserUK…

    I have files that contain ping travel times between nodes. I want to be able to graph this data using scatter graphs. (I would also like to create histograms with logarithmic scales. I have not found out how to do this in perl, so any advice you can give would be appreciated) The files contain over 8600 lines of data. Each line contains a timestamp and the time too and from the test site. I am not concerned about being able to see each single point. Most of the data will be grouped together and will form a line. This is just to be able to see a visual distribution of travel time in relation to time of day.
[reply]
      The files contain over 8600 lines of data.

      8640 data points (I'm assuming that you are pinging once every 10 seconds over each 24 hr period?), is not a lot of data. There really is no need to do you own thing. I just generated a 8640 timestamps/random times and plotted them on a 1024x768 points graph, and the total memory usage was well under 10 MB for the program, data and graph.

      Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
      "Science is about questioning the status quo. Questioning authority".
      In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
        Thanks, but when I originally ran my program the system slowed down and became sluggish. That is why I was trying to graph the file directly and not from an array. Do you know if this is possible? If not, then I'll just stick to using an array. Who knows, maybe its just the computer....
[reply]

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