Merge pull request #4 from marceljuenemann/sonneborn

Sonneborn-Berger

Author: marceljuenemann

README.md

@@ -12,6 +12,7 @@ Tiebreak is a TypeScript library for calculating various tournament tiebreak sco
 
 - Buchholz
 - Buchholz with modifiers (Cut-1, Cut-2, Median-1 etc.)
+- Sonneborn-Berger
 - (more to come)
 
 **Configurable adjustments for unplayed games:**

src/__tests__/tiebreak.test.ts

@@ -189,18 +189,66 @@ describe("TiebreakCalculation", () => {
     })
 
     /*
-    TODO: Test more modifiers with old FIDE unplayed rounds adjustments
-    - Cut-1
-    - Median-1
-    - Cut-2
-    - Very high cut numbers
+      TODO: Test more modifiers with old FIDE unplayed rounds adjustments
+      - Cut-1
+      - Median-1
+      - Cut-2
+      - Very high cut numbers
 
-    describe("with modifiers", () => {
+      describe("with modifiers", () => {
 
-    
+      })
+    */
+  })
+
+  describe("sonnebornBerger", () => {
+    describe("with FIDE_2023 unplayed rounds adjustment", () => {
+      it("should pass FIDE exercise 11 (2023)", async () => {
+        const rounds = await readTestCases("fide-exercise-2023")
+        const tiebreak = new Tiebreaker(rounds, UnplayedRoundsAdjustment.FIDE_2023)
+        expect(tiebreak.sonnebornBerger("1", 5)).toEqual(8)
+        expect(tiebreak.sonnebornBerger("3", 5)).toEqual(10.5)
+        expect(tiebreak.sonnebornBerger("16", 5)).toEqual(7.25)
+        expect(tiebreak.sonnebornBerger("4", 5)).toEqual(9.75)
+      })
 
+      it("should pass FIDE exercise 12 (2023)", async () => {
+        const rounds = await readTestCases("fide-exercise-2023")
+        const tiebreak = new Tiebreaker(rounds, UnplayedRoundsAdjustment.FIDE_2023)
+        expect(tiebreak.adjustedScore("2", 5)).toEqual(4)
+        expect(tiebreak.sonnebornBerger("2", 5)).toEqual(9.5)
+        expect(tiebreak.adjustedScore("3", 5)).toEqual(3.5)
+        expect(tiebreak.sonnebornBerger("3", 5)).toEqual(10.5)
+        expect(tiebreak.adjustedScore("4", 5)).toEqual(3.5)
+        expect(tiebreak.sonnebornBerger("4", 5)).toEqual(9.75)
+        expect(tiebreak.adjustedScore("1", 5)).toEqual(3.5)
+        expect(tiebreak.sonnebornBerger("1", 5)).toEqual(8)
+        expect(tiebreak.adjustedScore("16", 5)).toEqual(3.5)
+        expect(tiebreak.sonnebornBerger("16", 5)).toEqual(7.25)
+        expect(tiebreak.adjustedScore("6", 5)).toEqual(3)
+        expect(tiebreak.sonnebornBerger("6", 5)).toEqual(6.5)
+        expect(tiebreak.adjustedScore("11", 5)).toEqual(2.5)
+        expect(tiebreak.sonnebornBerger("11", 5)).toEqual(5.75)
+        expect(tiebreak.adjustedScore("8", 5)).toEqual(2.5)
+        expect(tiebreak.sonnebornBerger("8", 5)).toEqual(5.25)
+        expect(tiebreak.adjustedScore("5", 5)).toEqual(2.5)
+        expect(tiebreak.sonnebornBerger("5", 5)).toEqual(4.25)
+        expect(tiebreak.adjustedScore("14", 5)).toEqual(2)
+        expect(tiebreak.sonnebornBerger("14", 5)).toEqual(4.5)
+        expect(tiebreak.adjustedScore("12", 5)).toEqual(3.0)
+        expect(tiebreak.sonnebornBerger("12", 5)).toEqual(4.0)
+        expect(tiebreak.adjustedScore("15", 5)).toEqual(2)
+        expect(tiebreak.sonnebornBerger("15", 5)).toEqual(3.5)
+        expect(tiebreak.adjustedScore("13", 5)).toEqual(1.5)
+        expect(tiebreak.sonnebornBerger("13", 5)).toEqual(4.25)
+        expect(tiebreak.adjustedScore("7", 5)).toEqual(1.5)
+        expect(tiebreak.sonnebornBerger("7", 5)).toEqual(3.25)
+        expect(tiebreak.adjustedScore("10", 5)).toEqual(1.0)
+        expect(tiebreak.sonnebornBerger("10", 5)).toEqual(1.5)
+      })
     })
-    */
+
+    // TODO: Test with FIDE_2009 and NONE unplayed rounds adjustments.
   })
 
   describe("ranking", () => {
@@ -221,12 +269,17 @@ describe("TiebreakCalculation", () => {
       ])
       const tiebreak = new Tiebreaker(results, UnplayedRoundsAdjustment.FIDE_2023)
       expect(
-        tiebreak.ranking(2, [Tiebreak.SCORE, Tiebreak.BUCHHOLZ, Tiebreak.BUCHHOLZ_CUT1]),
+        tiebreak.ranking(2, [
+          Tiebreak.SCORE,
+          Tiebreak.BUCHHOLZ,
+          Tiebreak.BUCHHOLZ_CUT1,
+          Tiebreak.SONNEBORN_BERGER,
+        ]),
       ).toEqual([
-        { playerId: "B", rank: 1, scores: [2, 2.5, 2] }, // BH: 2 for unplayed + 0.5 for A
-        { playerId: "C", rank: 2, scores: [1.5, 2, 1.5] }, // BH: 0.5 for A + 1.5 for bye
-        { playerId: "A", rank: 3, scores: [0.5, 3.5, 2] }, // BH: 1.5 for C + 2 for B
-        { playerId: "D", rank: 4, scores: [0, 0, 0] }, // BH: 2 * 0 for unplayed rounds
+        { playerId: "B", rank: 1, scores: [2, 2.5, 2, 2.5] }, // BH: 2 for unplayed + 0.5 for A
+        { playerId: "C", rank: 2, scores: [1.5, 2, 1.5, 1.75] }, // BH: 0.5 for A + 1.5 for bye
+        { playerId: "A", rank: 3, scores: [0.5, 3.5, 2, 0.75] }, // BH: 1.5 for C + 2 for B
+        { playerId: "D", rank: 4, scores: [0, 0, 0, 0] }, // BH: 2 * 0 for unplayed rounds
       ])
     })
 

src/tiebreak.ts

@@ -2,6 +2,7 @@ import {
   PlayerId,
   PlayerResult,
   Results,
+  Score,
   isPaired,
   isPlayed,
   isVoluntarilyUnplayedRound,
@@ -27,6 +28,12 @@ export enum Tiebreak {
   BUCHHOLZ_CUT2 = "BH-C2",
   BUCHHOLZ_MEDIAN1 = "BH-M1",
   BUCHHOLZ_MEDIAN2 = "BH-M2",
+
+  /**
+   * Calculated by adding, for each round, a value given by multiplying the final
+   * score of the opponents by the points scored against them.
+   */
+  SONNEBORN_BERGER = "SB",
 }
 
 export enum UnplayedRoundsAdjustment {
@@ -64,7 +71,7 @@ export interface PlayerRanking {
 
 interface AdjustedGame {
   round: number
-  gameScore: number
+  gameScore: Score
   opponentScore: number
   isVur: boolean
 }
@@ -136,6 +143,9 @@ export class Tiebreaker {
         return this.buchholz(player, round, 1, 1)
       case Tiebreak.BUCHHOLZ_MEDIAN2:
         return this.buchholz(player, round, 2, 2)
+
+      case Tiebreak.SONNEBORN_BERGER:
+        return this.sonnebornBerger(player, round)
     }
   }
 
@@ -252,8 +262,16 @@ export class Tiebreaker {
     return this.sum(games.map((g) => g.opponentScore))
   }
 
+  /**
+   * Sonneborn-Berger score. Note that unplayed games are adjusted according to the configured UnplayedRoundsAdjustment.
+   */
+  public sonnebornBerger(player: PlayerId, round: number): number {
+    const games = this.adjustedGames(player, round)
+    return this.sum(games.map((g) => g.opponentScore * g.gameScore))
+  }
+
   // TODO: Maybe turn PlayerResult into a class which returns the score?
-  private scoreForResult(result: PlayerResult): number {
+  private scoreForResult(result: PlayerResult): Score {
     switch (result) {
       case "unpaired":
         return 0