why I get "out of memory" error when i use zeros(60000)?

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nadia 2015-11-16

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评论： Guillaume 2015-11-16

Hi. when I use zeros(60000) I receive out of memory error.My matlab product is MATLAB R2014a 64 bit. can you help me please?

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Answer 1

Thorsten 2015-11-16

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You tried to allocate 60000*60000*8 = 28.8 GByte. That's seems to be too much for Matlab on your machine.

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Thorsten 2015-11-16

编辑：Thorsten 2015-11-16

This traditional convention is not recommended, as far as I understand from https://en.wikipedia.org/wiki/Gigabyte:

In 1998 the International Electrotechnical Commission (IEC) published standards for binary prefixes, requiring that the gigabyte strictly denote 1000^3 bytes and gibibyte denote 1024^3 bytes. By the end of 2007, the IEC Standard had been adopted by the IEEE, EU, and NIST, and in 2009 it was incorporated in the International System of Quantities. Nevertheless, the term gigabyte continues to be widely used with the following two different meanings: [namely 1000^3 and 1024^3]

Guillaume 2015-11-16

Yes, the notation is not recommended. It is however the one used by the memory manufacturers and the one used by Windows to report the amount of memory your computer has.

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Answer 2

Guillaume 2015-11-16

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编辑：Guillaume 2015-11-16

在 MATLAB Online 中打开

zeros(60000) is the same as

zeros(60000, 60000)

A 60,000 x 60,000 matrix of doubles requires approximately 27 GB of memory.

If you just want a vector of 60,000 elements:

zeros(1, 60000)

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Stefan Raab 2015-11-16

在 MATLAB Online 中打开

Hey,

if you use the command

memory

you can see the Maximum possible array size. In my case:

Maximum possible array: 17896 MB (1.877e+10 bytes)

A double variable needs 64 bit or 8 byte of memory, so I can save 1.877e+10 bytes / 8 bytes = 2.3463e+09 double variables in one array. The resulting size for a quadratic matrix is then sqrt(2.3463e+09) = 48438. Therefore is a quadratic matrix with size 60000 too big.

Note: If there are many zeros in your matrix, I think you should have a look at sparse matrices: http://www.mathworks.com/help/matlab/ref/sparse.html

Kind regards, Stefan