How is the performance ELO calculated during a tournament

I find this performance ELO very comprehensive on how I did during a tournament; I'd be curious to know how is it calculated?
Does every individual move gets input into this or is it more the ratings of the opponents ?

I don't know although this seems like an interesting Q&A question:
http://en.lichess.org/qa

(Sum of opponents' ratings + 500 * (wins - losses)) / games.

github.com/ornicar/lila/blob/e4760befcc49766e1b3c2a3f21396e2998677d67/modules/tournament/src/main/Performance.scala

The ELO system uses 400 instead of 500.

gloriavictis101, this does not seem to work for me.

Can anyone elaborate on this?