How to add rows into existing .mat file?

I'm running a function (1) that read images, and then send each image into another function (2). function (2) is cropping 2000 patches from each image, and saves them.

I want to save 1 row of data (5 parameters) in a matrix for each patch.

At first I tried to create a global matrix and add row for each patch, but it make my script to be very slow.

So now I'm trying to save a .mat file on the disk, and then append rows there (instead of saving the matrix on the Matlab memory).

For conclusion: I'm looking for a way to add rows to existing .mat file, and I need this way to be fast (I have 3 millions rows)

Thanks a lot!

Answer 1

[Azzi Abdelmalek]

Look at this example, you can save your matrix as matrices of 100000 rows each for example

str='a':'z'
for k=1:10
  clear A;
  A.(str(k))=rand(4)
  save('file.mat','-struct','A','-append')
end