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