on the use of fastica

Hello, I'd be grateful if someone could help me understand why the result of

[icasig]=fastica(matrix, ..., 'numOfIC', 1)

is different each time I run the script. even if the fastica command is run within a loop with initialisation from previous step, I get always different results. Is this because my matrix is not large enough to ensure stability or is it due to initial random seeds? If the latter, how to avoid it?

many thanks