randomness/lib/tests/frequency-within-block-test.js

Randomness tests

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
const gamma_1 = require("../utils/gamma");
const counter_1 = require("../utils/counter");
const defaultBlockSize = 10;
const blockNumberMax = 100;
const sequenceSizeMin = 100;
const test = (bits, alpha = 0.01) => {
    const n = bits.length;
    if (n < sequenceSizeMin) {
        throw new Error('Too little data for test. Supply at least 100 bits');
    }
    let M = defaultBlockSize;
    let N = Math.floor(n / M);
    if (N > blockNumberMax) {
        N = blockNumberMax - 1;
        M = Math.floor(n / N);
    }
    const totalBlocks = N;
    const blockSize = M;
    const proportions = [];
    for (let i = 0; i < totalBlocks; i++) {
        const block = bits.slice(i * blockSize, (i + 1) * blockSize);
        const [_zeros, ones] = (0, counter_1.getCounts)(block);
        proportions.push(ones / blockSize);
    }
    let chiSquare = 0;
    for (let i = 0; i < proportions.length; i++) {
        chiSquare += 4 * blockSize * (proportions[i] - 1 / 2) ** 2;
    }
    const p = (0, gamma_1.gammaincc)(totalBlocks / 2, chiSquare / 2);
    const success = p >= alpha;
    return [success, p];
};
exports.default = test;
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