From eeaf0fdd339040663038b5b5c0afe53073fe6ded Mon Sep 17 00:00:00 2001 From: atomflunder <80397293+atomflunder@users.noreply.github.com> Date: Thu, 24 Nov 2022 12:51:05 +0100 Subject: [PATCH] Raise descriptive error instead of returning None --- CHANGELOG.md | 4 ++++ Cargo.toml | 2 +- README.md | 4 ++-- src/dwz.rs | 66 +++++++++++++++++++++++++++++++++++++++++----------- src/ingo.rs | 6 ++--- src/lib.rs | 4 ++-- 6 files changed, 64 insertions(+), 22 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index 0f40bce..015b4e3 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -2,6 +2,10 @@ This is a broad overview of the changes that have been made over the lifespan of this library. +## v0.21.0 - 2022-11-24 + +- Return a more descriptive error on `get_first_dwz` function instead of returning None + ## v0.20.0 - 2022-11-06 - Added FIFA rating algorithm (Men) diff --git a/Cargo.toml b/Cargo.toml index 2d4109b..f734ef8 100644 --- a/Cargo.toml +++ b/Cargo.toml @@ -1,6 +1,6 @@ [package] name = "skillratings" -version = "0.20.0" +version = "0.21.0" edition = "2021" description = "Calculate a player's skill rating using algorithms like Elo, Glicko, Glicko-2, TrueSkill and many more." readme = "README.md" diff --git a/README.md b/README.md index ec6a164..a7f97df 100644 --- a/README.md +++ b/README.md @@ -39,7 +39,7 @@ Alternatively, you can add the following to your `Cargo.toml` file manually: ```toml [dependencies] -skillratings = "0.20" +skillratings = "0.21" ``` ### Serde support @@ -56,7 +56,7 @@ By editing `Cargo.toml` manually: ```toml [dependencies] -skillratings = {version = "0.20", features = ["serde"]} +skillratings = {version = "0.21", features = ["serde"]} ``` ## Usage and Examples diff --git a/src/dwz.rs b/src/dwz.rs index 30f45d3..6625994 100644 --- a/src/dwz.rs +++ b/src/dwz.rs @@ -46,7 +46,7 @@ //! - [Official DWZ scoring system rules (German)](https://www.schachbund.de/wertungsordnung.html) //! - [Probability Table](https://www.schachbund.de/wertungsordnung-anhang-2-tabellen/articles/wertungsordnung-anhang-21-wahrscheinlichkeitstabelle.html) -use std::collections::HashMap; +use std::{collections::HashMap, error::Error, fmt::Display}; #[cfg(feature = "serde")] use serde::{Deserialize, Serialize}; @@ -121,6 +121,29 @@ impl From for DWZRating { } } +#[derive(Debug, Clone, Copy, PartialEq, Eq)] +/// The error types that can occur when calculating a new DWZ Rating. +/// Only gets raised in the [`get_first_dwz`] function. +pub enum GetFirstDWZError { + /// The player has played less than 5 games. + NotEnoughGames, + /// The player has a winrate of 0% or 100%. + InvalidWinRate, +} + +impl Display for GetFirstDWZError { + fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { + match self { + Self::NotEnoughGames => { + write!(f, "You need at least 5 games to calculate a DWZ Rating.") + } + Self::InvalidWinRate => write!(f, "Your winrate cannot be 0% or 100%."), + } + } +} + +impl Error for GetFirstDWZError {} + #[must_use] /// Calculates new [`DWZRating`] of two players based on their old rating, index, age and outcome of the game. /// @@ -259,7 +282,6 @@ pub fn dwz( /// assert_eq!(new_player.index, 18); /// ``` pub fn dwz_rating_period(player: &DWZRating, results: &[(DWZRating, Outcomes)]) -> DWZRating { - // DWZ was designed to be used in tournaments, so we do not need to loop over the opponents here. let points = results.iter().map(|r| r.1.to_chess_points()).sum(); let expected_points = results.iter().map(|r| expected_score(player, &r.0).0).sum(); @@ -317,7 +339,6 @@ pub fn expected_score(player_one: &DWZRating, player_two: &DWZRating) -> (f64, f (exp_one, exp_two) } -#[must_use] /// Gets a proper first [`DWZRating`]. /// /// In the case that you do not have enough opponents to rate a player against, @@ -327,8 +348,11 @@ pub fn expected_score(player_one: &DWZRating, player_two: &DWZRating) -> (f64, f /// Takes in the player's age and their results as a Slice of tuples containing the opponent and the outcome. /// If the actual player's age is unavailable or unknown, choose something `>25`. /// -/// This only returns a DWZ rating if the results include at least 5 matches, -/// and you don't have a 100% or a 0% win record. Otherwise it will return [`None`]. +/// +/// # Errors +/// +/// This function returns [`GetFirstDWZError::NotEnoughGames`] if the player has played less than 5 games, +/// or [`GetFirstDWZError::InvalidWinRate`] if the player has a winrate of either 0% or 100%. /// /// # Examples /// ``` @@ -378,16 +402,19 @@ pub fn expected_score(player_one: &DWZRating, player_two: &DWZRating) -> (f64, f /// assert!((player.rating - 1491.0).abs() < f64::EPSILON); /// assert_eq!(player.index, 1); /// ``` -pub fn get_first_dwz(player_age: usize, results: &[(DWZRating, Outcomes)]) -> Option { +pub fn get_first_dwz( + player_age: usize, + results: &[(DWZRating, Outcomes)], +) -> Result { if results.len() < 5 { - return None; + return Err(GetFirstDWZError::NotEnoughGames); } let points: f64 = results.iter().map(|r| r.1.to_chess_points()).sum(); // If you have a 100% or 0% win rate, we return None. if (points - results.len() as f64).abs() < f64::EPSILON || points == 0.0 { - return None; + return Err(GetFirstDWZError::InvalidWinRate); } let average_rating = results.iter().map(|r| r.0.rating).sum::() / results.len() as f64; @@ -457,12 +484,12 @@ pub fn get_first_dwz(player_age: usize, results: &[(DWZRating, Outcomes)]) -> Op let mut new_rating = if p > 50 { // If the performance is positive, we convert the values above to a positive number. // The value for 30 is the same as for 70, but negative. - let temp = probability_table.get(&(p - 100).abs())?; + let temp = probability_table.get(&(p - 100).abs()).unwrap_or(&0.); f64::abs(*temp) + average_rating } else { // Else we just use the negative number above. - probability_table.get(&p)? + average_rating + probability_table.get(&p).unwrap_or(&0.) + average_rating }; // If the rating would be too low we revise it upwards. @@ -470,7 +497,7 @@ pub fn get_first_dwz(player_age: usize, results: &[(DWZRating, Outcomes)]) -> Op new_rating = 700.0 + (new_rating / 8.0); } - Some(DWZRating { + Ok(DWZRating { rating: new_rating, index: 1, age: player_age, @@ -733,7 +760,7 @@ mod tests { ], ); - assert_eq!(all_win_player, None); + assert_eq!(all_win_player, Err(GetFirstDWZError::InvalidWinRate)); let all_lose_player = get_first_dwz( 17, @@ -746,7 +773,7 @@ mod tests { ], ); - assert_eq!(all_lose_player, None); + assert_eq!(all_lose_player, Err(GetFirstDWZError::InvalidWinRate)); let less_than_5 = get_first_dwz( 32, @@ -758,7 +785,7 @@ mod tests { ], ); - assert_eq!(less_than_5, None); + assert_eq!(less_than_5, Err(GetFirstDWZError::NotEnoughGames)); } #[test] @@ -882,5 +909,16 @@ mod tests { DWZRating::from((1400.0, 20)), DWZRating::from((1400.0, 20, 26)) ); + + assert!(!format!("{:?}", GetFirstDWZError::NotEnoughGames).is_empty()); + assert!(!format!("{:?}", GetFirstDWZError::InvalidWinRate).is_empty()); + + assert!(!format!("{}", GetFirstDWZError::NotEnoughGames).is_empty()); + assert!(!format!("{}", GetFirstDWZError::InvalidWinRate).is_empty()); + + assert_eq!( + GetFirstDWZError::NotEnoughGames, + GetFirstDWZError::NotEnoughGames.clone() + ); } } diff --git a/src/ingo.rs b/src/ingo.rs index bd6d717..086938e 100644 --- a/src/ingo.rs +++ b/src/ingo.rs @@ -336,7 +336,7 @@ mod tests { fn test_ingo_rating_period() { let player_one = IngoRating { rating: 130.0, - age: 40, + age: 22, }; let player_two = IngoRating { rating: 160.0, @@ -361,7 +361,7 @@ mod tests { let player_four = IngoRating { rating: 55.0, - age: 40, + age: 22, }; let player_five = IngoRating { @@ -378,7 +378,7 @@ mod tests { let p1 = ingo_rating_period(&player_one, &results); - assert!((p1.rating.round() - 126.0).abs() < f64::EPSILON); + assert!((p1.rating.round() - 124.0).abs() < f64::EPSILON); } #[test] diff --git a/src/lib.rs b/src/lib.rs index cd253b5..c1e5219 100644 --- a/src/lib.rs +++ b/src/lib.rs @@ -47,7 +47,7 @@ //! //! ```toml //! [dependencies] -//! skillratings = "0.20" +//! skillratings = "0.21" //! ``` //! //! ## Serde support @@ -64,7 +64,7 @@ //! //! ```toml //! [dependencies] -//! skillratings = {version = "0.20", features = ["serde"]} +//! skillratings = {version = "0.21", features = ["serde"]} //! ``` //! //! # Usage and Examples