diff --git a/server/ladders-local.ts b/server/ladders-local.ts
index ec24da06198af..1c4745dc03595 100644
--- a/server/ladders-local.ts
+++ b/server/ladders-local.ts
@@ -172,30 +172,7 @@ export class LadderStore {
updateRow(row: LadderRow, score: number, foeElo: number) {
let elo = row[1];
- // The K factor determines how much your Elo changes when you win or
- // lose games. Larger K means more change.
- // In the "original" Elo, K is constant, but it's common for K to
- // get smaller as your rating goes up
- let K = 50;
-
- // dynamic K-scaling (optional)
- if (elo < 1200) {
- if (score < 0.5) {
- K = 10 + (elo - 1000) * 40 / 200;
- } else if (score > 0.5) {
- K = 90 - (elo - 1000) * 40 / 200;
- }
- } else if (elo > 1350 && elo <= 1600) {
- K = 40;
- } else {
- K = 32;
- }
-
- // main Elo formula
- const E = 1 / (1 + Math.pow(10, (foeElo - elo) / 400));
- elo += K * (score - E);
-
- if (elo < 1000) elo = 1000;
+ elo = this.calculateElo(elo, score, foeElo);
row[1] = elo;
if (score > 0.6) {
@@ -334,4 +311,35 @@ export class LadderStore {
}
return Promise.all(ratings);
}
+
+ /**
+ * Calculates Elo based on a match result
+ */
+ private calculateElo(previousUserElo: number, score: number, foeElo: number): number {
+ // The K factor determines how much your Elo changes when you win or
+ // lose games. Larger K means more change.
+ // In the "original" Elo, K is constant, but it's common for K to
+ // get smaller as your rating goes up
+ let K = 50;
+
+ // dynamic K-scaling (optional)
+ if (previousUserElo < 1200) {
+ if (score < 0.5) {
+ K = 10 + (previousUserElo - 1000) * 40 / 200;
+ } else if (score > 0.5) {
+ K = 90 - (previousUserElo - 1000) * 40 / 200;
+ }
+ } else if (previousUserElo > 1350 && previousUserElo <= 1600) {
+ K = 40;
+ } else {
+ K = 32;
+ }
+
+ // main Elo formula
+ const E = 1 / (1 + Math.pow(10, (foeElo - previousUserElo) / 400));
+
+ const newElo = previousUserElo + K * (score - E);
+
+ return Math.max(newElo, 1000);
+ }
}
diff --git a/server/ladders-remote.ts b/server/ladders-remote.ts
index 72ecdefee9fba..65d0ebe094bc4 100644
--- a/server/ladders-remote.ts
+++ b/server/ladders-remote.ts
@@ -70,25 +70,43 @@ export class LadderStore {
const formatid = this.formatid;
const p1 = Users.getExact(p1name);
const p2 = Users.getExact(p2name);
- room.update();
- room.send(`||Ladder updating...`);
- const [data, error] = await LoginServer.request('ladderupdate', {
+
+ const ladderUpdatePromise = LoginServer.request('ladderupdate', {
p1: p1name,
p2: p2name,
score: p1score,
format: formatid,
});
+
+ // calculate new Elo scores and display to room while loginserver updates the ladder
+ const [p1OldElo, p2OldElo] = (await Promise.all([this.getRating(p1!.id), this.getRating(p2!.id)])).map(Math.round);
+ const p1NewElo = Math.round(this.calculateElo(p1OldElo, p1score, p2OldElo));
+ const p2NewElo = Math.round(this.calculateElo(p2OldElo, 1 - p1score, p1OldElo));
+
+ const p1Act = (p1score > 0.9 ? `winning` : (p1score < 0.1 ? `losing` : `tying`));
+ let p1Reasons = `${p1NewElo - p1OldElo} for ${p1Act}`;
+ if (!p1Reasons.startsWith('-')) p1Reasons = '+' + p1Reasons;
+ room.addRaw(Utils.html`${p1name}'s rating: ${p1OldElo} → ${p1NewElo}
(${p1Reasons})`);
+
+ const p2Act = (p1score > 0.9 || p1score < 0 ? `losing` : (p1score < 0.1 ? `winning` : `tying`));
+ let p2Reasons = `${p2NewElo - p2OldElo} for ${p2Act}`;
+ if (!p2Reasons.startsWith('-')) p2Reasons = '+' + p2Reasons;
+ room.addRaw(Utils.html`${p2name}'s rating: ${p2OldElo} → ${p2NewElo}
(${p2Reasons})`);
+
+ room.rated = Math.min(p1NewElo, p2NewElo);
+
+ if (p1) p1.mmrCache[formatid] = +p1NewElo;
+ if (p2) p2.mmrCache[formatid] = +p2NewElo;
+
+ room.update();
+
+
+ const [data, error] = await ladderUpdatePromise;
let problem = false;
if (error) {
- if (error.message === 'stream interrupt') {
- room.add(`||Ladder updated, but score could not be retrieved.`);
- } else {
- room.add(`||Ladder (probably) updated, but score could not be retrieved (${error.message}).`);
- }
problem = true;
} else if (!room.battle) {
- Monitor.warn(`room expired before ladder update was received`);
problem = true;
} else if (!data) {
room.add(`|error|Unexpected response ${data} from ladder server.`);
@@ -108,37 +126,7 @@ export class LadderStore {
return [p1score, null, null];
}
- let p1rating;
- let p2rating;
- try {
- p1rating = data!.p1rating;
- p2rating = data!.p2rating;
-
- let oldelo = Math.round(p1rating.oldelo);
- let elo = Math.round(p1rating.elo);
- let act = (p1score > 0.9 ? `winning` : (p1score < 0.1 ? `losing` : `tying`));
- let reasons = `${elo - oldelo} for ${act}`;
- if (!reasons.startsWith('-')) reasons = '+' + reasons;
- room.addRaw(Utils.html`${p1name}'s rating: ${oldelo} → ${elo}
(${reasons})`);
- let minElo = elo;
-
- oldelo = Math.round(p2rating.oldelo);
- elo = Math.round(p2rating.elo);
- act = (p1score > 0.9 || p1score < 0 ? `losing` : (p1score < 0.1 ? `winning` : `tying`));
- reasons = `${elo - oldelo} for ${act}`;
- if (!reasons.startsWith('-')) reasons = '+' + reasons;
- room.addRaw(Utils.html`${p2name}'s rating: ${oldelo} → ${elo}
(${reasons})`);
- if (elo < minElo) minElo = elo;
- room.rated = minElo;
-
- if (p1) p1.mmrCache[formatid] = +p1rating.elo;
- if (p2) p2.mmrCache[formatid] = +p2rating.elo;
- room.update();
- } catch (e) {
- room.addRaw(`There was an error calculating rating changes.`);
- room.update();
- }
- return [p1score, p1rating, p2rating];
+ return [p1score, data!.p1rating, data!.p2rating];
}
/**
@@ -149,4 +137,37 @@ export class LadderStore {
static async visualizeAll(username: string) {
return [`| Please use the official client at play.pokemonshowdown.com |
`];
}
+
+ /**
+ * Calculates Elo for quick display, matching the formula on loginserver
+ */
+ // see lib/ntbb-ladder.lib.php in the pokemon-showdown-client repo for the login server implementation
+ // *intentionally* different from calculation in ladders-local, due to the high activity on the main server
+ private calculateElo(previousUserElo: number, score: number, foeElo: number): number {
+ // The K factor determines how much your Elo changes when you win or
+ // lose games. Larger K means more change.
+ // In the "original" Elo, K is constant, but it's common for K to
+ // get smaller as your rating goes up
+ let K = 50;
+
+ // dynamic K-scaling (optional)
+ if (previousUserElo < 1100) {
+ if (score < 0.5) {
+ K = 20 + (previousUserElo - 1000) * 30 / 100;
+ } else if (score > 0.5) {
+ K = 80 - (previousUserElo - 1000) * 30 / 100;
+ }
+ } else if (previousUserElo > 1300) {
+ K = 40;
+ } else if (previousUserElo > 1600) {
+ K = 32;
+ }
+
+ // main Elo formula
+ const E = 1 / (1 + Math.pow(10, (foeElo - previousUserElo) / 400));
+
+ const newElo = previousUserElo + K * (score - E);
+
+ return Math.max(newElo, 1000);
+ }
}