The size of largest matrix that can be inverted

Hi all,

What is the size of the largest square matrix that can be inverted in MATLAB.

Thanks in advance. V

Answer 1

[Sean de Wolski]

With a 64 bit machine and a lot of RAM, it can be pretty big. Fortunately, you almost never have to take it. Please read Loren's Blog and the comments associated with ti:

Loren's_Blog

And of course the doc for inv which also discourages this: doc inv

Answer 2

[the cyclist]

The answer to this question is platform and MATLAB version dependent. I think this is going to largely depend on the largest array you can store. You can get some guidance on maximum array size here: http://www.mathworks.com/support/tech-notes/1100/1110.html

I have 64-bit MATLAB 2011b running on a Mac, with 8 GB of RAM, and it inverted a 10,000x10,000 in about 2 minutes.

You should ask yourself whether you really need to do the matrix inversion or not. Very frequently, you can avoid taking the inverse, in favor of some less-intensive computation.

[Ingo]

May I ask how much RAM your computer got? Mine has 4GB and that seems not to be nearly enough to even store a 6.000-by-6.000 (full, nonsparse) matrix.

[the cyclist]

Edited my answer to address Ingo's comment.

[Ingo]

Thanks!