You have already named the file, including the .mat extension, so you don’t need to include it in the sprintf argument list. It is creating problems, because it overflows the numeric fields in your edit descriptor, adding the ‘_109_97_116_’ as it writes the ASCII values of 'mat' to your file name string.
This illustrates the problem:
Q = int8('mat')
Q =
109 97 116
I’m otherwise not certain how to interpret your save call.
