Dear Pierre,

I think I have found the solution of this problem.

I have modified 'fopen('1.txt', 'w')' in the script 'psom_run_script.m' to 'fopen(['~' filesep '1.txt'], 'w')'.
As we know, in the linux '~' is a symbol of the personal directory, so this command will create file 1.txt in the personal directory of the user and there is no permission problem.

Best wishes

Zaixu