Tall arrays - how do they work

Hi,

I am working with ECG signals with multiple leads. I stack the signal from the different leads in a tensor. The tensor variable takes up approximately 6 GB space. However, when running Discrete Wavelet Transform (DWT) followed by Empirical Mode Decomposition (EMD), the end result is much much more than 6 GB. I have 20 tensors in the tensor variable (20 patients) and after running DWT and EMD, the data for each patient will be around 6 GB, so it takes up a lot of space!

I am therefore thinking about using tall arrays instead as they seem to take up much less space. My idea is to store the tensor variable in a tall array and then running DWT and EMD. Will this be possible? If yes, how is the indexing for tall arrays? The tensor variable is a cell array so I use {} a lot.

Thanks!

Answer 1

[Kavya Vuriti]

Hi,

Though you can convert cell array into a tall array, you cannot use dwt function because the input to dwt function cannot be tall array. Instead different versions of mat file are available to store large data which is obtained after performing 'DWT' and 'EMD'.

For more information, refer the following link:https://www.mathworks.com/help/matlab/import_export/mat-file-versions.html

Also you can use matfile function to store large data. Here is the documentation link for matfile function.