Topic: Rating system

trimard wrote:

Ok I'm having some trouble storing decimal value it seems in django. Anyone has experience in that?

I don't have experience either. But as I remember: some database types don't support decimals, but all of them supports float. And float for our calculations should be enough to store all data. Python can easily show the values by "%.3f" % value (float value would be showed as 3-decimal digits number stored as string).
Another workaround is to use integer instead (as it is done in Widelands model for soldiers - their HP is stored like that).

But where you want to use decimals instead of floats?

Also, I've been rethinking about what Worlsavior said. Maybe we could already start a tread to call for games? People that post the result of their match in the post will have a ranking! And it would give us lots of data to play with I guess we would still some kind of rules. Like both players have to post that they want to join the ranking before playing the game otherwise it doesn't count?

That is a good idea!

Database models for ranking games and ladder

Recently I was thinking how to solve the models for games and players. The problem was split into two parts:

1. Game models
2. Ranking values models

For Game models we need lots of data, but the data can be also split into two parts: specific game data & players (and teams) data. Plus we want to support not only 2-players games, but every possible Widelands game too. That makes the system more complicated.

For that we need at least two models: game model and participant model. Game model will contain data like map, win conditions, timestamps, and so on. Participant model will create many-to-many relation between game model and registered user model, plus it should contain data like which team the player was playing with, how many interruptions were on that player side (future use?) and so on.

And for coding stuff, arbiter can have access to django admin page, where on a game model form can be several inlines of participants and it will be quite easy to add any records or edit them.

For rank models I was thinking about one that will contain join to the registered user, rank values (two integers and two floats for beginning), update time (when rank record was created) and if it is an active one. Why the last "active"? Because if we create that, we can easily store data about previous rank values and then we can see whole history of the player. And why I am thinking about integer values for ranking? Because then we can easily support simpliest win/lose rank too.

I understand that you may have another view on the problem, so I am open for your point of view .

einstein13
calculations & maps packages: http://wuatek.no-ip.org/~rak/widelands/
backup website files: http://kartezjusz.ddns.net/upload/widelands/

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Also, I've been rethinking about what Worlsavior said. Maybe we could already start a tread to call for games? People that post the result of their match in the post will have a ranking! And it would give us lots of data to play with I guess we would still some kind of rules. Like both players have to post that they want to join the ranking before playing the game otherwise it doesn't count?

Definitely - players should always decide whether a match is ranked or not before they start playing.

Busy indexing nil values

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I think using a models.DecimalField is good. See also python Decimal

Yes, that's what I tried but I'm having trouble making it work. I always get the same bug: "[<class 'decimal.InvalidOperation'>]" When trying to store any number with the django model I showed in the upper messages. Even if I put Decimal(1500) or Decimal (0.1) or anything. Same bug. And I cannot find much documentation for that bug. Only the "max_digits should be higher than decimal_places"

Django's error message isn't really helpful...

One doesn't has to fiddle with roundings of values then, imho.

Ha, that's a good point in keeping this format then, yes. I'm not so used to math in code, so any simplification is beneficial. Well that is, if I can fix this bug

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trimard wrote:

Yes, that's what I tried but I'm having trouble making it work. I always get the same bug: "[<class 'decimal.InvalidOperation'>]" When trying to store any number with the django model I showed in the upper messages. Even if I put Decimal(1500) or Decimal (0.1) or anything. Same bug. And I cannot find much documentation for that bug. Only the "max_digits should be higher than decimal_places"

max_digits is the overall amount of digits, that's the digits in the left of the decimal separator plus the digits on the right of the decimal separator.

volatility = models.DecimalField(max_digits=5, decimal_places=2)

= overall digits of 5, three on the left and two on the right of the separator. Trying to apply a value of 1500 does not work, because the left part (integers) can only have 3 digits. '0.1' should work though, maybe it should be '0,1' (note the comma instead of the point). Don't really know, but it may depends on your settings of locales. If you're on linux try this command:

locale -k LC_NUMERIC

The output from my machine:

decimal_point=","
thousands_sep="."
grouping=3;3
numeric-decimal-point-wc=44
numeric-thousands-sep-wc=46
numeric-codeset="UTF-8"

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I am sorry for technical language (for those who doesn't like it)

trimard wrote:

Database models for ranking games and ladder

Here's what I have for now for my first test. A lot of stuff are missing but I'm looking for functionality first (...)

class Game(models.Model):

    CHOICES_GAME_TYPE = ((1, 'Autocrat'), (2, 'Wood gnome'), ...)

    start_date = modelsDateTimeField()
    type = models.IntegerField(choices=CHOICES_GAME_TYPE)
    map = models.CharField(max_length=255)
    # here we can think about expanding to FK to uploaded maps too:
    # map_link = models.ForeignKey('?maps.map?', null=True, blank=True)
    win_team = models.IntegerField(null=True, blank=True) # blank when game not finished
    submitter = models.ForeignKey(User, related_name='submitted_games')

class Participant(models.Model):
    player = models.ForeignKey(User, related_name='played_games')
    game = models.ForeignKey(Game, related_name='participants')
    team = models.IntegerField()

class Rating(models.Model):

    CHOICES_TYPE = ((1, 'simple'), (2, 'Elo'), (3, 'Glicko'))
    CHOICES_SUBTYPE = ((1, 'updated instantly'), (2, 'updated weekly'))

    player = models.ForeignKey(User, related_name='ratings')
    type = models.IntegerField(choices=CHOICES_TYPE )
    subtype = models.IntegerField(choices=CHOICES_SUBTYPE )
    rating = models.DecimalField(max_digits=6, decimal_places=2)
    float1 = models.FloatField(null=True, blank=True) # rating_deviation for Glicko
    float2 = models.FloatField(null=True, blank=True) # volatility for Glicko
    integer1 = models.IntegerField(null=True, blank=True) # number of win games for simple ladder
    integer2 = models.IntegerField(null=True, blank=True) # number of lost games for simple ladder
    updated = models.DateTimeField(auto_now_add=True)
    active = models.BooleanField(default=True)

    def save(self):
        if self.id == None:
            # update previous records (if exist) of the same type & subtype to be inactive
            previous = Rating.objects.filter(active=True)
            previous = previous.filter(type=self.type)
            if self.subtype:
                previous = previous.filter(subtype=self.subtype)
            previous.update(active=False)
        super().save() # for Python 3.X
        super(Rating, self).save() # for Python 2.7
        return

And when you want to register new game, let's say between me and you (and you win), you will get:

Game records: 1

Game:
    id = 1
    start_date = 2019-07-28 22:00:00
    type = 1 # autocrat
    map = "Ice Wars"
    win_team = 2
    submitter = 253 # einstein13, example ID

Participants records: 2

Participant:
    id = 1
    player = 253 # einstein13
    game = 1 # record above
    team = 1

Participant:
    id = 2
    player = 355 # trimard
    game = 1 # record above
    team = 2

Rating records: 4

Rating:
    player = 253 # einstein13
    type = 1 # simple ladder
    subtype = 1 # updated instantly
    rating = 0.00
    # float1 & float2 are empty
    integer1 = 0
    integer2 = 1
    updated = 2019-07-28 23:13:31
    active = True

Rating:
    player = 355 # trimard
    type = 1 # simple ladder
    subtype = 1 # updated instantly
    rating = 1000.00 # max value
    # float1 & float2 are empty
    integer1 = 1
    integer2 = 0
    updated = 2019-07-28 23:13:31
    active = True

Rating:
    player = 253 # einstein13
    type = 3 # glicko
    subtype = 1 # updated instantly
    rating = 1467.79
    float1 = 327.58
    float2 = 0.059998
    # integer1 & integer2 are empty
    updated = 2019-07-28 23:13:31
    active = True

Rating:
    player = 355 # trimard
    type = 3 # glicko
    subtype = 1 # updated instantly
    rating = 1532.21
    float1 = 327.58
    float2 = 0.059998
    # integer1 & integer2 are empty
    updated = 2019-07-28 23:13:31
    active = True

Values are only for example purpose, the are not very strict

Is my idea clearer now? Hope so
I know that it is completely different than yours.

I am not sure if you like it or not, but since Widelands is a doocracy and since you are developing the tools, you make a choice

Why didn't I think about that? The first thing I did was a page for the arbiter to enter data...

Nicely done!

And why I am thinking about integer values for ranking? Because then we can easily support simpliest win/lose rank too.

I'm not sure I understand that part

The simpliest idea for rank I know is to find proportion of win/all games. And since "rating" is providing decimals, the (almost) most precise equation for rank value would be:

ranking = 1000.0 * number_of_win_games / (number_of_win_games + number_of_lost_games)
ranking = 1000.0 * self.integer1 / (self.integer1 + self.integer2)

And to be honest, my idea is covering more than one ranking at once, plus more than only one type of games (1 vs. 1) for them. But if you stick to your approach, that also will be very good!

einstein13
calculations & maps packages: http://wuatek.no-ip.org/~rak/widelands/
backup website files: http://kartezjusz.ddns.net/upload/widelands/

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