making a big dat(binary) file

Hello people, I need to make a single binary file containing several sessions of electrophysiological recordings. The dat file needs to be a matrix where every single row is a single channel and columns represent samples. My old Matlab code did the dat file by creating a matrix(ch x samp) first, writing down the matrix into the dat file, cleaning up memory and starting with the next session. It works well but, somedays I have sessions where the data matrix is bigger than the memory capacity of my machine. Making Matlab running out of memory.

Been able to write down channel by channel into the dat file I think it could work. Did someone know if that is possible? Inserting a row by row into the dat file using a loop?

It is my understanding that fwrite writes in column order. Is it possible to have a code that writes in row order?

Thanks,

[dpb]

Just transpose array x on output --

fwrite(fid,x.')

But will still have groups of data of Nsamp x Mchan in each block in the file.

Probably simplest is to modify the file structure slightly to write the block size each time first.

If you have existing files, add a version ID as the first value in the file that you can scan and test for...then your code can handle either version.

[PEDRO FELICIANO]

I'll try that. Thanks.

Answer 1

[Rajani Mishra]

As mentioned in previous comment you can take transpose of array x and thus column by column data can be written.

Also I found a similar question : https://www.mathworks.com/matlabcentral/answers/351069-how-can-i-save-each-column-of-a-matrix-as-separate-dat-file

[PEDRO FELICIANO]

I'll try that, thanks.