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