Memory mapping matrices

memory mapping and accessing matrices

Description

making and accessing files via memory mapping. very useful when working with a very large data sets/matrices. instead of loading the whole matrix , you can access just specific part of it. very efficient.

• MATLAB release: MATLAB 7.3 (R2006b)
• Other requirements: nonee

[ron ganor]

An excellent way to implement the memory mapping capabilities of matlab. Very efficient, very well done.
Maybe the data handling way of the future? ...
Recomende

[Claudiu Giurumescu]

It works in 7.1SP3 too. Updated both scripts a bit so that different data types are handled correctly. Definitely solves my memory problems. Great idea.

[Anton Sirota]

Nice that you brought that up. memmapfile does make the binary file operations much less painful and more elegant.
just wanted to comment: in my experience reading/writing (actually, both can be implemented with memmampfile) consecutive samples from/to binary file with memmapfile is not much different in terms of memory usage and speed from buffered fread/fwrite (with varying offset, skip, format) given that buffer size is chosen accordingly. It seems after all what matters is file caching by the OS. Also, so far even 64bit version of MATLAB under true 64bit Linux doesn't allow mapping more that 2^31-1, thus limiting you to 2GB file size, if you wanted to map it all.

[Tarik Akbudak]

could you explain how to assign complex data types too?? because it is not allowed to assign complex numbers in matrices.