Create large complex matfile

Hello,

how can you create a large complex array in a matfile without allocating memory for the whole array?

The following works perfectly well for real data:

matObj = matfile(filename, 'Writable', true);
matObj.data(rows,cols,channels,channels) = 0;

I tried changing it to:

matObj = matfile(filename, 'Writable', true);
matObj.data(rows,cols,channels,channels) = 1i;

which raises the following error:

The class and attributes of the right hand side could
not be converted into the type of the variable in the
file.

Thank you in advance!

Answer 1

[Walter Roberson]

Just make sure that the first thing written is complex.

If the array is not already complex in the file, you will probably need to rewrite it all.

Note: if you need a complex value that happens to be (0,0) then use

complex(0,0)

[Johannes]

Thanks! The problem was that the file actually already existed on disk with the variable being real.