| import { IMetricResponse, IMetricRequest } from "./IFairnessProps"; |
| import { ParityModes } from "./ParityMetrics"; |
|
|
| export class MetricsCache { |
| private static readonly defaultKeys = ["falsePositiveRate", "falseNegativeRate"]; |
|
|
| |
| private cache: Array<Array<{[key: string]: IMetricResponse}>>; |
| constructor(private featureCount: number, |
| private numberOfModels: number, |
| private fetchMethod: (request: IMetricRequest) => Promise<IMetricResponse>) { |
| this.cache = new Array(featureCount).fill(0).map(y => new Array(numberOfModels).fill(0).map(x => {return {};})); |
| } |
|
|
| public async getMetric(binIndexVector: number[], featureIndex: number, modelIndex: number, key: string): Promise<IMetricResponse> { |
| let value = this.cache[featureIndex][modelIndex][key]; |
| if (value === undefined) { |
| value = await this.fetchMethod({ |
| metricKey:key, |
| binVector: binIndexVector, |
| modelIndex: modelIndex |
| }); |
| this.cache[featureIndex][modelIndex][key] = value; |
| } |
| return this.cache[featureIndex][modelIndex][key]; |
| } |
|
|
| public async getDisparityMetric(binIndexVector: number[], featureIndex: number, modelIndex: number, key: string, disparityMethod: ParityModes): Promise<number> { |
| let value = this.cache[featureIndex][modelIndex][key]; |
| if (value === undefined) { |
| value = await this.fetchMethod({ |
| metricKey: key, |
| binVector: binIndexVector, |
| modelIndex: modelIndex |
| }); |
| this.cache[featureIndex][modelIndex][key] = value; |
| } |
|
|
| const bins = value.bins.slice().filter(x => x !== undefined && !isNaN(x)); |
|
|
| const min = Math.min(...(bins as number[])); |
| const max = Math.max(...(bins as number[])); |
| if (isNaN(min) || isNaN(max) || (max === 0 && disparityMethod === ParityModes.ratio)) { |
| return Number.NaN; |
| } |
| return disparityMethod === ParityModes.difference ? |
| max - min : |
| min / max; |
| } |
|
|
| public clearCache(binIndex?: number): void { |
| if (binIndex !== undefined) { |
| this.cache[binIndex] = new Array(this.numberOfModels).fill(0).map(x => {return {};}); |
| } else { |
| this.cache = new Array(this.featureCount).fill(0).map(y => new Array(this.numberOfModels).fill(0).map(x => {return {};})); |
| } |
| } |
| } |
