Rating formula [question]

[bl4de]

Hi,

First of all - thanks guys for CTFtime.org, it's great idea to aggregate all CTF-related things in one place. Taking a part in CTFs is one of the best way to learn new things.

I've got a question about rating formula. I've created simple Python script to calculate points taken in CTF for CTFtime overall ranking. However, results returned from this script are quite different from points showed on CTFtime page.

This is my script:

#!/usr/bin/python
#
# CTF event points -> CTFtime.org ranking points calculator
# Rating formula see: https://ctftime.org/rating-formula/
#
#
# Calculates team's points from CTF for CTFtime.org overall ranking
#


def calculate():
    rating = 0.0

    points_coef = float(team_points) / best_points
    place_coef = float(1) / team_place

    if points_coef > 0:
        rating = ((points_coef + place_coef) * weight) / (1 + float(team_place)/total_teams)

    return rating

if __name__ == '__main__':

    team_place = int(raw_input("your team place in CTF: "))
    team_points = int(raw_input("earned CTF points: "))
    total_teams = int(raw_input("teams with any points (more than 0) in CTF: "))
    best_points = int(raw_input("winner team points: "))
    weight = int(raw_input("CTF event rating weight (by CTFtime.org): "))

    print "\n### Your team earned {0:.4f} points in this CTF, congrats! ###"\
        .format(calculate())

And this is sample output (calculated rating points from Boston Key Party 2015 - https://ctftime.org/event/163 - yeah, I know, my points are totally hopeless, but I'm a total beginner and I'm playing alone... ):

your team place in CTF: 285
earned CTF points: 170
teams with any points (more than 0) in CTF: 822
winner team points: 6445
CTF event rating weight (by CTFtime.org): 60

### Your team earned 1.3315 points in this CTF, congrats! ###

On my team page there are 1,793 added points after Boston Key Party 2015.

How can I apply total_team_ranking in my script? Is this causing this difference? I'd be grateful for help.

If this issue is not appropriate here, please close/remove it :) I just didn't know where and who could I ask for this. Thank you.

[kyprizel]

Sorry, the formula on the picture is incorrect - correct denominator is 1/(1+(team_place/total_teams)).

[bl4de]

Now it's working perfect, thanks!