glicko v0.1.0 Glicko.Player

A convenience wrapper that handles conversions between glicko versions one and two.

Usage

Create a player with the default values for an unrated player.

iex> Player.new_v2
%Player{version: :v2, rating: 0.0, rating_deviation: 2.014761872416068, volatility: 0.06}

Create a player with custom values.

iex> Player.new_v2([rating: 1500, rating_deviation: 50, volatility: 0.05])
%Player{version: :v2, rating: 1500, rating_deviation: 50, volatility: 0.05}

Convert a v2 player to a v1. Note this drops the volatility.

iex> Player.new_v2 |> Player.to_v1
%Player{version: :v1, rating: 1.5e3, rating_deviation: 350.0, volatility: nil}

Convert a v1 player to a v2.

iex> Player.new_v1 |> Player.to_v2(0.06)
%Player{version: :v2, rating: 0.0, rating_deviation: 2.014761872416068, volatility: 0.06}

Note calling to_v1 with a v1 player or likewise with to_v2 and a v2 player will pass-through unchanged. The volatility arg in this case is ignored.

iex> player_v2 = Player.new_v2
iex> player_v2 == Player.to_v2(player_v2)
true

Link to this section Summary

Functions

Creates a new v1 player

Creates a new v2 player

A convenience function for summarizing a player’s strength as a 95% confidence interval

Scales a players rating deviation

Scales a players rating

Converts a v2 player to a v1

Converts a v1 player to a v2

Link to this section Types

Link to this type t()
t() :: v1_t() | v2_t()
Link to this type v1_t()
v1_t() :: %Glicko.Player{rating: float(), rating_deviation: float(), version: :v1, volatility: nil}
Link to this type v2_t()
v2_t() :: %Glicko.Player{rating: float(), rating_deviation: float(), version: :v2, volatility: float()}

Link to this section Functions

Link to this function new_v1(opts \\ [])
new_v1([rating: float(), rating_deviation: float()]) :: v1_t()

Creates a new v1 player.

If not overriden, will use default values for an unrated player.

Link to this function new_v2(opts \\ [])
new_v2([rating: float(), rating_deviation: float(), volatility: float()]) :: v2_t()

Creates a new v2 player.

If not overriden, will use default values for an unrated player.

Link to this function rating_interval(player)
rating_interval(player :: t()) :: {rating_low :: float(), rating_high :: float()}

A convenience function for summarizing a player’s strength as a 95% confidence interval.

The lowest value in the interval is the player’s rating minus twice the RD, and the highest value is the player’s rating plus twice the RD. The volatility measure does not appear in the calculation of this interval.

An example would be if a player’s rating is 1850 and the RD is 50, the interval would range from 1750 to 1950. We would then say that we’re 95% confident that the player’s actual strength is between 1750 and 1950.

When a player has a low RD, the interval would be narrow, so that we would be 95% confident about a player’s strength being in a small interval of values.

Link to this function scale_rating_deviation_to(rating_deviation, atom)
scale_rating_deviation_to(rating_deviation :: float(), to_version :: :v1 | :v2) :: float()

Scales a players rating deviation.

Link to this function scale_rating_to(rating, atom)
scale_rating_to(rating :: float(), to_version :: :v1 | :v2) :: float()

Scales a players rating.

Link to this function to_v1(player)
to_v1(player :: t()) :: v1_t()

Converts a v2 player to a v1.

A v1 player will pass-through unchanged.

Note the volatility field used in a v2 player will be lost in the conversion.

Link to this function to_v2(player, volatility \\ 0.06)
to_v2(player :: t(), volatility :: float()) :: v2_t()

Converts a v1 player to a v2.

A v2 player will pass-through unchanged with the volatility arg ignored.