commit 2101e6d093d31b23502bfba7aeae54b887bd69c8 Author: Matei Adriel Date: Sun Jan 20 22:13:44 2019 +0200 javascript(linear-regression): first commit Signed-off-by: prescientmoon diff --git a/javascript/linear-regression/index.html b/javascript/linear-regression/index.html new file mode 100644 index 0000000..fbbc860 --- /dev/null +++ b/javascript/linear-regression/index.html @@ -0,0 +1,31 @@ + + + + + Linear regression + + + + + + + + + + + + + + diff --git a/javascript/linear-regression/js/main.js b/javascript/linear-regression/js/main.js new file mode 100644 index 0000000..f32bc05 --- /dev/null +++ b/javascript/linear-regression/js/main.js @@ -0,0 +1,101 @@ +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]; +}