What is the largest number of rows of a matrix that Matlab can handle?

What is the largest number of rows of a matrix that Matlab can handle? How can one know that limit in my PC?

[alpedhuez]

https://www.mathworks.com/matlabcentral/answers/266758-increase-limit-on-matrix-size

[Rik]

You need to better define your question. What does handling mean? Does that only include the creation of the array? Does that include acceptable performance when applying operations? If so, what is acceptable performance and what operations?

For your specific computer, you can test it yourself. We shouldn't need to read your mind or look through the >270 questions you have posted to see what hardware you're using.

[alpedhuez]

I have posted the answer by myself above.

[madhan ravi]

Post it as an answer.

Answer 1

[Walter Roberson]

2^45-1 rows is the limit for MATLAB arrays.

Answer 2

[Steven Lord]

The theoretical limit is the number returned as the second output of the computer function.

The practical limit is based on how much memory you have on your system, as it's highly unlikely you have a machine capable of creating a matrix large enough to approach the theoretical limit (unless it's a sparse tall but thin matrix.)

>> x = sparse(2^48-1, 1, 1)

x =

    (281474976710655,1)                       1

>> x = sparse(2^48, 1, 1)
Error using sparse
Index into matrix is too large.

In 32-bit releases of MATLAB, it was much easier to reach the theoretical limit.

[Walter Roberson]

You have to divide that second output of computer by 8 to get maximum index, because it takes 8 bytes to represent the size of each dimension and the total size of the list of dimensions has to be less than 2^48.

[Steven Lord]

>> [comptype, maxsize] = computer
comptype =
    'PCWIN64'

maxsize =
           281474976710655

The sparse x I created has exactly maxsize rows.

If you tried to create an array with an extremely large number of dimensions then yes, you'd consume a lot of memory with the size vector. In this example z only has two elements but it takes a little while to create.

x = [ones(1, 1e8), 2];
z = ones(x);
whos z

[Bruno Luong]

That's interesting. I believe some older MATLAB release the limits is about 2^32 (not a lot) even for 64-bits PC. Not sure if it's a limits of conception or internal overflow bug. Glad to see TMW push this boundary further away. I might revisit my test to see if the issue I found earlier is indeed solved.