52 lines
1.2 KiB
JavaScript
52 lines
1.2 KiB
JavaScript
function get_primes7(n) {
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if (n < 2) { return []; }
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if (n == 2) { return [2]; }
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var s = [];
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for (var i = 3; i < n + 1; i += 2) {
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s.push(i);
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}
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var mroot = Math.floor(Math.sqrt(n));
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var half = s.length;
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var i = 0;
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var m = 3;
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while (m <= mroot) {
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if (s[i]) {
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var j = Math.floor((m*m-3)/2); // int div
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s[j] = 0;
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while (j < half) {
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s[j] = 0;
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j += m;
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}
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}
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i = i + 1;
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m = 2*i + 3;
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}
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// due to a bug in node.js 4.3, we need to declare and init on separate lines
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// or else node.js performs about four times slower
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var res = [];
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res.push(2);
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for (var x = 0; x < s.length; x++) {
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if (s[x]) {
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res.push(s[x]);
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}
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}
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return res;
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}
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var startTime = Date.now();
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var periodTime = parseInt(process.env.RUN_TIME || '5', 10) * 1000;
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var iterations = 0;
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while ((Date.now() - startTime) < periodTime || iterations < 3) {
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var res = get_primes7(10000000);
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console.log("Found " + res.length + " prime numbers.");
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iterations++;
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}
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var time = Date.now() - startTime;
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var per30 = time / 1000 / iterations * 30;
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console.log(iterations + " iterations in "+(Math.round(time/10)/100)+" seconds = "+(Math.round(per30*100)/100)+" seconds per 30 iterations");
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