Core Concepts

Core Library Reference

This page documents the @opprs/core calculation library. If you're running the full OPPRS stack (REST API + Frontend), these calculations are handled automatically. This reference is for developers who want to understand the algorithms or integrate the library into custom applications.

This page explains the fundamental concepts and calculations used in the OPPRS ranking system.

Base Value

The base value of a tournament is calculated based on the number of rated players (players with 5+ events):

• 0.5 points per rated player
• Maximum of 32 points (achieved at 64+ rated players)

import { calculateBaseValue } from '@opprs/core';

const baseValue = calculateBaseValue(players);

Tournament Value Adjustment (TVA)

TVA increases tournament value based on the strength of the field:

Rating-based TVA

• Uses Glicko ratings to assess player skill
• Maximum contribution: 25 points
• Formula: (rating * 0.000546875) - 0.703125

Ranking-based TVA

• Uses world rankings to assess field strength
• Maximum contribution: 50 points
• Formula: ln(ranking) * -0.211675054 + 1.459827968

import { calculateRatingTVA, calculateRankingTVA } from '@opprs/core';

const ratingTVA = calculateRatingTVA(players);
const rankingTVA = calculateRankingTVA(players);

Tournament Grading Percentage (TGP)

TGP measures the quality and completeness of a tournament format:

• Base value: 4% per meaningful game
• Without separate qualifying: Max 100%
• With qualifying and finals: Max 200%

Multipliers

Format	Multiplier
4-player groups	2X
3-player groups	1.5X
Unlimited best game (20+ hours)	2X
Hybrid best game	3X
Unlimited card qualifying	4X

import { calculateTGP, type TGPConfig } from '@opprs/core';

const tgpConfig: TGPConfig = {
  qualifying: {
    type: 'limited',
    meaningfulGames: 7,
  },
  finals: {
    formatType: 'match-play',
    meaningfulGames: 15,
    fourPlayerGroups: true,
  },
};

const tgp = calculateTGP(tgpConfig);

Event Boosters

Event boosters multiply the final tournament value:

Booster Type	Multiplier
None	1.0X (100%)
Certified	1.25X (125%)
Certified+	1.5X (150%)
Championship Series	1.5X (150%)
Major	2.0X (200%)

import { getEventBoosterMultiplier } from '@opprs/core';

const booster = getEventBoosterMultiplier('major'); // Returns 2.0

Point Distribution

Points are distributed using two components:

1. Linear Distribution (10%): Evenly distributed across positions
2. Dynamic Distribution (90%): Heavily weighted toward top finishers

import { distributePoints } from '@opprs/core';

const distributions = distributePoints(results, firstPlaceValue);

Time Decay

Points decay over time to emphasize recent performance:

Time Period	Value Retained
0-1 years	100%
1-2 years	75%
2-3 years	50%
3+ years	0% (inactive)

import { applyTimeDecay, isEventActive } from '@opprs/core';

const eventDate = new Date('2023-01-01');
const decayedPoints = applyTimeDecay(100, eventDate);
const active = isEventActive(eventDate);

Glicko Rating System

Player ratings use the Glicko system with rating deviation (uncertainty):

• Default rating: 1300
• Rating deviation (RD): 10-200
• RD decay: ~0.3 per day of inactivity

import { updateRating, type RatingUpdate } from '@opprs/core';

const update: RatingUpdate = {
  currentRating: 1500,
  currentRD: 100,
  results: [
    { opponentRating: 1600, opponentRD: 80, score: 1 }, // Win
    { opponentRating: 1550, opponentRD: 90, score: 0 }, // Loss
  ],
};

const { newRating, newRD } = updateRating(update);