Loading large array within a struct

I am trying to access a mat file which contains an array of size 256x256x6x20000.

I have tried with matfile. But the problem is mat file stored in a way where this array resides within a struct. I need to go through three levels to access these array. (Example- data.training.images.data). How can I partially load this array with matfile() ?

[per isakson]

That's not possible with matfile()

See https://se.mathworks.com/matlabcentral/answers/463639-handling-large-data-sets#answer_376426 and search the File Exchange for tag:memmapfile

[Soumik Mohian]

Thanks for the reply.

h5read works.