I thought for sure I had outlined this in the user manual, but I guess not...
Logarithm method:
N = log((numberOfPlayers + 1) / rank)
This is then averaged over the set of tournaments. Finally, the N is plugged into this formula to obtain the final score:
score = (1 - exp(-N)) * 100
* Note that the log() function is log base e.
Percentile method:
score = (1 - (rank / (numberOfPlayers + 1))) * 100
This is then averaged over the set of tournaments to obtain the final score.