Memory Issues: Almost like clear doesn't fully work
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I am running 32b vista, Matlab 2009a. The machine has 4GB of RAM installed, PAE & 3G switch activated. the machine is dedicated to MATLAB and doesn't run anything else.
I have code that reads and writes data from disk. Data is stored in the form of txt files. There are thousands of text files around 200MB each in size. The code loads the text file into RAM processes it and then writes it back to disk.
Each load is done within a loop
for i = 1: numFiles
loadAndWriteData(file(i))
end
function loadAndWriteData(file)
load file
do stuff
save file
clear file (and all other variables I can see lurking around)
end
hence any RAM intensive processes are done in loadAndWriteData.m This returns on each call of the for loop.
I use memory.m to inspect the memomry availble to me. I see that after a few runs around the available memory starts dropping off. Then Matlab crashes with an out of RAM error.
I would have thought that as the function is returning each time around the loop, I would be nicely clearing everything in RAM.
What I am doing wrong? Any help gratefully received. thank you.
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More Answers (3)
mathworks2011
on 21 Apr 2011
2 Comments
Jason Ross
on 21 Apr 2011
Your suggestion of quitting MATLAB and starting again isn't so nonsensical. If this program was amenable to using functions from the parallel computing toolbox, you can set the RestartWorker on the job object to do exactly that.
http://www.mathworks.com/help/toolbox/distcomp/restartworker.html
Matt Fig
on 21 Apr 2011
How are you clearing the files? Are you using FCLOSE and checking the return variable?
EDIT
I am not certain that clearing the file identifier will close the file. I don't see it in the documentation...
fid = fopen('myfile')
clear fid % Is the file in memory or not?
fclose(fid) % Does using this instead of clear help???
5 Comments
Matt Fig
on 21 Apr 2011
A script is an M-file which has no keyword: function in it. For example, this is would be a function M-file:
function B = mysquare(A)
B = A.^2;
and this would be a script M-file:
B = A.^2;
The script will actually execute in the base workspace, and so can call PACK. To change a function to a script, simply copy and paste all of the code into a new M-file. Note that scripts can call function M-files, so just put the bare-bones in a script, then you can call PACK and other command line functions.
aasim Azooz
on 22 Apr 2011
Try this for i = 1: numFiles loadAndWriteData(file(i)) clear all end
if it does not work, you may have a virus in your computer. It happened with me. everything went fine after I scanned my PC for viruses. good Luck Aasim Azooz
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