// A simple smoke test and benchmark for the generators.
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var assert = require('assert');
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var xor128 = require('../lib/xor128');
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var xorwow = require('../lib/xorwow');
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var xs7 = require('../lib/xorshift7');
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var xor4096 = require('../lib/xor4096');
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var tychei = require('../lib/tychei');
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var alea = require('../lib/alea');
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var sr = require('../seedrandom');
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describe("XOR-Shift generator test", function() {
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var benchmarks = { native: { rand: Math.random, times: [] } };
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function test(label, alg, double1, float3, int4, hc, qc, ec, e2c) {
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var fn = alg(1);
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var fn2 = alg('hello.', { state: true });
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benchmarks[label] = {rand: fn.quick, times: []};
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it("should use " + label + " correctly", function() {
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if (double1 != null) assert.equal(fn.double(), double1);
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if (float3 != null) assert.equal(fn.quick(), float3);
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if (int4 != null) assert.equal(fn.int32(), int4);
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assert(fn() > 0);
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assert(fn() < 1);
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assert(fn2() > 0);
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// Internal state is visible only if requested.
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assert(!('state' in fn));
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assert('state' in fn2);
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var ss = fn2.state();
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var rs = fn2();
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assert(rs < 1);
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var j, h = 0, q = 0, e = 0, r, p, e2 = 0;
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for (j = 0; j < 1024; ++j) {
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r = fn();
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if (r < 0.5) h += 1;
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if (r < 0.25) q += 1;
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if (r < 0.125) e += 1;
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r2 = fn2();
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if (r2 < 0.125) e2 += 1;
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}
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if (hc != null) {
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assert.equal(h, hc);
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assert.equal(q, qc);
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assert.equal(e, ec);
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assert.equal(e2, e2c);
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h = q = e = p = 0;
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for (j = 0; j < 1024; ++j) {
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r = fn.double();
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if (r < 0.5) h += 1;
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if (r < 0.25) q += 1;
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if (r < 0.125) e += 1;
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if (fn.int32() >= 0) p += 1;
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}
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// Sanity-check double() and int32.
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assert(h >= 480 && h <= 543, h);
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assert(q >= 226 && q <= 286, q);
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assert(e >= 100 && e <= 156, e);
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assert(e2 >= 100 && e2 <= 156, e2);
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assert(p >= 482 && p <= 543, p);
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}
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var fn3 = alg(0, { state: ss });
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assert.equal(fn3(), rs);
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});
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}
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test("xor128", xor128,
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0.7963797148975774, 0.22171171731315553, 317177041, 498, 236, 110, 115);
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test("xorwow", xorwow,
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0.8178000247146859, 0.8407576507888734, 533150816, 519, 228, 121, 123);
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test("xorshift7", xs7,
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0.21241471533241418, 0.9957620368804783, -1678071207, 510, 261, 143, 124);
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test("tychei", tychei,
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0.42331440041340196, 0.9365617581643164, -884984569, 521, 242, 116, 126);
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test("seedrandom", sr,
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0.1776348083296759, 0.2160690303426236, 1397712774, 526, 282, 131, 137);
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test("xor4096", xor4096,
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0.1520436450538547, 0.4206166828516871, 1312695376, 496, 241, 113, 142);
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test("alea", alea,
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0.5260470956849501, 0.47771977609954774, -1625913352, 494, 246, 125, 122);
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it("runs benchmarks", function() {
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var n = 4;
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var trials = 10;
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var top = 4;
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this.timeout(200 * n * trials);
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this.slow(30 * n * trials);
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var fn, k, start, end, j, t;
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for (k in benchmarks) {
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fn = benchmarks[k].rand;
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// warmup.
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for (j = 0; j < 1e5; ++j) fn();
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}
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for (t = 0; t < trials; ++t) {
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for (k in benchmarks) {
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fn = benchmarks[k].rand;
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start = +new Date;
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// benchmark.
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for (j = 0; j < n * 1e5; ++j) fn();
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end = +new Date;
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benchmarks[k].times.push(end - start);
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}
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}
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for (k in benchmarks) {
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benchmarks[k].times.sort();
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}
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function fastest(array) {
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var sum = 0;
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for (var j = 0; j < top; ++j) {
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sum += array[j];
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}
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return sum / top;
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}
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var nativetime = fastest(benchmarks.native.times);
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for (k in benchmarks) {
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var time = fastest(benchmarks[k].times);
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console.log(k+ ': ' + time / n + ' nanoseconds per call, ' +
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(time / nativetime).toFixed(1) + 'x native random.');
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}
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});
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});
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