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Overcome matrix maximum size problem

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Talaria
Talaria on 7 Aug 2011
how could i possibly overcome the problem of being limited by matrix maximum size. i am thinking of maybe storing values to a file? is this possible?
suppose i have a code that lists a matrix of all binary possibilities from 0 to n, if n is too great the matrix would not be enough to store all values. what would be a good solution? also considering RAM limitations.

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Jan
Jan on 7 Aug 2011
Accessing the harddisk is about 1000 times slower than RAM access. And if the calculation of the permutations of more than 52 symbols (from your last post) takes some years, writing this to the disk will exceed the life time of the computer in every case.
The solution is easy: Do not do this. There is simply no reason to calculate a giantic array which such a tiny density of information. It will be more efficient to create the single lines (or rows) dynamically. For permutations this can be done e.,g. by:
  2 Comments
Jan
Jan on 7 Aug 2011
@walter: You are right. The binary string problem is not a "permutation", but a "combination with repetitions". I spend much time to implement the 4 very efficient VChooseK(R)(O) as C-Mex in the FEX, but I still confuse the terms.
Thanks, Walter. As usual it is helpful to know, that you catch errors!

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More Answers (1)

the cyclist
the cyclist on 7 Aug 2011
It is possible to store values in files. Refer to the documentation on the "save" and "load" commands.
  1 Comment
Talaria
Talaria on 7 Aug 2011
i meant saving data values, elements of matrix.
is this what you mean?

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