Why do I receive an 'Out of Memory' error using FREAD function when my file is smaller than the largest contiguous memory block?

I have a large binary file of uint16 data named fname. It smaller than the largest free memory block. When I execute the following commands:

fid=fopen('fname');

F=fread(fid,'uint16')

I receive the following result:

 ??? Error using ===> fread.

 Out of memory. Type HELP MEMORY for your options

Answer 1

[MathWorks Support Team]

Here, the 'uint16' refers to how to interpret the data in the file and not how to represent it in MATLAB. Thus, class(F) will return double, so the FILESIZE * sizeof(double)/sizeof(uint16) will be larger than the memory block and out of memory error is expected.

To work around this issue, use the 'uint16=>uint16' option to FREAD to make MATLAB interpret the data as uint16 and also store it in MATLAB as uint16. This can be done using either of the following commands

1. F = fread(fid,'uint16=>uint16');

2. F = fread(fid,'*uint16');