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javascript(linear-regression): first commit

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Signed-off-by: prescientmoon <git@moonythm.dev>
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Matei Adriel 2019-01-20 22:13:44 +02:00 committed by prescientmoon
commit 2101e6d093
Signed by: prescientmoon
SSH key fingerprint: SHA256:UUF9JT2s8Xfyv76b8ZuVL7XrmimH4o49p4b+iexbVH4
2 changed files with 132 additions and 0 deletions
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javascript/linear-regression/index.html Normal file
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<!DOCTYPE html>
<html lang="en" dir="ltr">
<head>
<meta charset="utf-8">
<title>Linear regression</title>
<!-- via CDN -->
<script src="https://cdn.jsdelivr.net/npm/mainloop.js@latest/build/mainloop.min.js"></script>
<script
src="https://code.jquery.com/jquery-3.3.1.slim.min.js"
integrity="sha256-3edrmyuQ0w65f8gfBsqowzjJe2iM6n0nKciPUp8y+7E="
crossorigin="anonymous"></script>
<script defer src="js/main.js" charset="utf8"></script>
<style>
body,html{
margin:0px;
padding:0px;
height:100%;
width:100%;
display:block;
overflow-y:hidden;
}
</style>
</head>
<body>
<canvas id="canvas"></canvas>
</body>
</html>

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javascript/linear-regression/js/main.js Normal file
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const canvas = document.getElementById("canvas");
const ctx = canvas.getContext("2d");
canvas.height = window.innerHeight;
canvas.width = window.innerWidth;
const w = window.innerWidth;
const h = window.innerHeight;
const points = [];
const pointSize = 5;
const shuffleProcent = 0.99;
let pressing = false;
let a = 1;
let b = 0;
let rate = 0.5;
const sumArrays = (a,c) => [a[0] + c[0],a[1] + c[1]];
MainLoop.setDraw(() => {
ctx.fillStyle = "#000000";
ctx.fillRect(0,0,3000,3000);
ctx.fillStyle = "#ffffff";
for (let i of points){
ctx.fillRect(i[0] * w,i[1] * h,pointSize,pointSize);
}
ctx.strokeStyle = "#8888ff";
ctx.beginPath();
ctx.moveTo(0,b * h);
ctx.lineTo(w,h * a + h * b);
ctx.stroke();
if (points.length > 1){
let good = regression();
ctx.strokeStyle = "#22ff55";
ctx.beginPath();
ctx.moveTo(0,h * good[1]);
ctx.lineTo(w,h * good[0] + h * good[1]);
ctx.stroke();
}
}).setUpdate(train).start();
$(canvas).mousedown((e) => {pressing = true});
$(canvas).mouseup((e) => {pressing = false});
$(canvas).mousemove(e => {
if (pressing){
points.push([
e.clientX/w,
e.clientY/h
]);
}
});
function shuffle(a) {
var j, x, i;
for (i = a.length - 1; i > 0; i--) {
j = Math.floor(Math.random() * (i + 1));
x = a[i];
a[i] = a[j];
a[j] = x;
}
return a;
}
function train(time){
if (Math.random() > shuffleProcent) points = shuffle(points);
let lastcost = Math.pow(10,20);
if (points.length > 1){
for (let i of points){
const x = i[0];
const y = i[1];
let guess = a * x + b;
let error = y - guess;
a = a + error * rate * x;
b = b + error * rate;
guess = a * x + b;
newerror = y - guess;
}
}
}
function regression(){
const sum = points.reduce(sumArrays);
const mean = sum.map(val => val/points.length);
let den = 0;
let num = 0;
for (let i of points){
num += (i[0] - mean[0]) * (i[1] - mean[1]);
den += (i[0] - mean[0]) * (i[0] - mean[0]);
}
let m = num/den;
let n = mean[1] - m * mean[0];
return [m,n];
}