js计算散点图方程式

//pointArrayX,pointArrayY 为两个数组，分别为x轴对应的点和y轴对应的点

function getEquationPara(pointArrayX, pointArrayY) {

    var abr = [];

    var xavg = eval(pointArrayX.join("+")) / pointArrayX.length;

    var yavg = eval(pointArrayY.join("+")) / pointArrayY.length;

    var a, b, r;

    var xysum = 0, xxsum = 0;

    var divider = 0, dividend = 0, xxavgsum = 0, yyavgsum = 0;

    for (var i = 0; i < pointArrayX.length; i++) {

        xysum += pointArrayX[i] * pointArrayY[i];

        xxsum += pointArrayX[i] * pointArrayX[i];

        dividend += (pointArrayX[i] - xavg) * (pointArrayY[i] - yavg);

        xxavgsum += (pointArrayX[i] - xavg) * (pointArrayX[i] - xavg);

        yyavgsum += (pointArrayY[i] - yavg) * (pointArrayY[i] - yavg);

    }

    b = (xysum - pointArrayX.length * xavg * yavg) / (xxsum - (pointArrayX.length * xavg * xavg));

    a =fomatFloat(PointFloat(yavg - b * xavg,4),3);//fomatFloat--四舍六入方法，查看详细

if (a==0) { a = "0.0"; } b = fomatFloat(b, 4); divider = fomatFloat(Math.sqrt(xxavgsum) * Math.sqrt(yyavgsum), 5); r = dividend / divider; abr.push(a); abr.push(b); abr.push(r.toString().substr(0, 6)); return abr; }

function PointFloat(src, pos) {

return Math.round(src * Math.pow(10, pos)) / Math.pow(10, pos);
}

秒客网

js计算散点图方程式

相关文章