chrisp/brackt
1
1
Fork 0
Code Issues 42 Pull requests Projects Releases Packages Wiki Activity Actions 1

fix: seed darts bracket by Elo instead of world ranking

Browse source 
World ranking (PDC Order of Merit) is prize-money-based and can diverge
from current skill — e.g. Kevin Doets (1818 Elo) was ranked 35th while
Joe Cullen (1667 Elo) held the 32nd seed. Seeding the weaker player and
leaving the stronger one unseeded contradicts the Elo-based match model.

Seeding by Elo descending ensures the 32 strongest players (by the same
metric used to compute match probabilities) get protected bracket positions.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
Chris Parsons 2026-04-09 04:24:53 +00:00
parent d5c39d3270
commit 2387173cf5
1 changed files with 9 additions and 12 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

21
app/services/simulations/darts-simulator.ts
View file

@ -29,7 +29,7 @@
* Final: best-of-13 sets, first to 7 * Final: best-of-13 sets, first to 7
* *
* Seeding (pre-bracket path): * Seeding (pre-bracket path):
* Top 32 players (by world ranking) are seeded into fixed bracket positions * Top 32 players (by Elo, descending) are seeded into fixed bracket positions
* using the standard balanced bracket structure: * using the standard balanced bracket structure:
* R1 seeds: 1v32, 16v17, 9v24, 8v25 (top half) + 5v28, 12v21, 13v20, 4v29 * R1 seeds: 1v32, 16v17, 9v24, 8v25 (top half) + 5v28, 12v21, 13v20, 4v29
* 3v30, 14v19, 11v22, 6v27 (bottom half) + 7v26, 10v23, 15v18, 2v31 * 3v30, 14v19, 11v22, 6v27 (bottom half) + 7v26, 10v23, 15v18, 2v31
@ -468,17 +468,14 @@ export class DartsSimulator implements Simulator {
// the seeded tour players. // the seeded tour players.
const fallbackElo = 1400; const fallbackElo = 1400;
// Sort participants by world ranking (ascending). Fall back to Elo order (descending) for // Seed by Elo descending — the top 32 strongest players (by Elo) get protected
// any without a ranking, then alphabetical as a final tiebreak. // bracket positions. World ranking (PDC Order of Merit) is prize-money-based and
const sorted = [...allParticipants].toSorted((a, b) => { // can diverge from current skill; a player ranked 35th by earnings might have a
const rankA = rankingMap.get(a.id); // higher Elo than someone ranked 28th. Using Elo for seeding keeps the bracket
const rankB = rankingMap.get(b.id); // consistent with the Elo-based match simulation.
if (rankA !== undefined && rankB !== undefined) return rankA - rankB; const sorted = [...allParticipants].toSorted((a, b) =>
if (rankA !== undefined) return -1; // ranked before unranked (eloMap.get(b.id) ?? fallbackElo) - (eloMap.get(a.id) ?? fallbackElo)
if (rankB !== undefined) return 1; );
// Both unranked — sort by Elo descending
return (eloMap.get(b.id) ?? fallbackElo) - (eloMap.get(a.id) ?? fallbackElo);
});
const topSeeds = sorted.slice(0, TOP_SEEDS).map((p) => p.id); // seeds 1–32 const topSeeds = sorted.slice(0, TOP_SEEDS).map((p) => p.id); // seeds 1–32
const unseeded = sorted.slice(TOP_SEEDS).map((p) => p.id); // remaining players const unseeded = sorted.slice(TOP_SEEDS).map((p) => p.id); // remaining players