34 lines
1.2 KiB
TypeScript
34 lines
1.2 KiB
TypeScript
import { describe, expect, test } from 'vitest';
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import { buildGoertzelCoefficients, goertzelPower } from '@openreader/compute-core';
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function dftPower(samples: Float32Array, k: number): number {
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const n = samples.length;
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let re = 0;
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let im = 0;
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for (let i = 0; i < n; i += 1) {
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const angle = (-2 * Math.PI * k * i) / n;
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re += samples[i] * Math.cos(angle);
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im += samples[i] * Math.sin(angle);
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}
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return (re * re) + (im * im);
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}
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describe('whisper spectral helpers', () => {
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test('goertzel power matches direct DFT for non-power-of-two frame size', () => {
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const frameSize = 400;
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const bins = 201;
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const coeffs = buildGoertzelCoefficients(bins, frameSize);
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const samples = new Float32Array(frameSize);
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for (let i = 0; i < frameSize; i += 1) {
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samples[i] = Math.sin((2 * Math.PI * 37 * i) / frameSize) + (0.2 * Math.cos((2 * Math.PI * 91 * i) / frameSize));
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}
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const testBins = [0, 7, 37, 91, 150, 200];
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for (const k of testBins) {
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const expected = dftPower(samples, k);
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const actual = goertzelPower(samples, coeffs[k]);
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const rel = Math.abs(actual - expected) / Math.max(1, Math.abs(expected));
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expect(rel).toBeLessThan(1e-5);
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}
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});
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});
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