pep8261 already answered - however a simple what to view profit factor is: it's simple the gross profit divided by the gross loss. A profit factor of 1 is break even, the system lost as must as it gained. 

an very simply way to view profit fact is:  For every dollar you lost, what did you gain. For example, a profit factor of 3 would mean that for every $1 you lost, you made $3. 

A profit factor of 50 means that for every $dollar the system lost, it made $50, or 50 fold over the losses

that's why profit factors of 3 are considered great because it's 3:1 gain vs the lost. And why profit factors of 50 and 100 are just insane because it's 50:1 or 100:1