62 lines
1.7 KiB
JavaScript
62 lines
1.7 KiB
JavaScript
const express = require('express');
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const cors = require('cors');
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const app = express();
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const Decimal = require('decimal.js');
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app.use(cors());
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function calculatePi(n) {
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Decimal.config({ precision: n * 14 });
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let pi = new Decimal(0);
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let k = 0; // Using a simple integer for k
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let x = new Decimal(1);
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const sixteen = new Decimal(16);
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for (let i = 0; i < n; i++) {
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// Precompute common terms to avoid recalculating them
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const denominator1 = new Decimal(8).times(k).plus(1);
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const denominator2 = new Decimal(8).times(k).plus(4);
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const denominator3 = new Decimal(8).times(k).plus(5);
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const denominator4 = new Decimal(8).times(k).plus(6);
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// Calculate the contributions to pi
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const term1 = Decimal.div(4, denominator1);
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const term2 = Decimal.div(2, denominator2);
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const term3 = Decimal.div(1, denominator3);
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const term4 = Decimal.div(1, denominator4);
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// Update pi with the calculated terms
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pi = pi.plus(term1.minus(term2).minus(term3).minus(term4).times(x));
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// Increment k and update x
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k++;
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x = x.div(sixteen);
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}
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return pi;
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}
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app.get('/pi', (req, res) => {
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const precision = parseInt(req.query.precision);
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if (isNaN(precision)) {
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return res.status(400).json({ error: 'Invalid precision parameter' });
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}
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const startTime = performance.now();
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const pi = calculatePi(precision);
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const endTime = performance.now();
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const duration = (endTime - startTime).toFixed(6);
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res.json({
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pi: pi.toFixed(precision),
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time: `${duration}ms`,
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language: 'Node.js'
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});
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});
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const PORT = 8083;
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console.log(`Node.js server starting on port ${PORT}...`);
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app.listen(PORT); |