Optimization Suggestion

[wu-wenzhi]

When I use dotted line style , the display line is lopsidedness.
My suggestion code (take linear regression for example)
`var predata = dataPreprocess(data);
var sumX = 0;
var sumY = 0;
var sumXY = 0;
var sumXX = 0;
var len = predata.length;

                        var min = 0;
                        var max = 0;

                        for (var i = 0; i < len; i++) {
                            sumX += predata[i][0];
                            sumY += predata[i][1];
                            sumXY += predata[i][0] * predata[i][1];
                            sumXX += predata[i][0] * predata[i][0];

                            if (max <= predata[i][0]) {
                                max = predata[i][0];
                            }
                            if (min >= predata[i][0]) {
                                min = predata[i][0];
                            }
                        }

                        var gradient = ((len * sumXY) - (sumX * sumY)) / ((len * sumXX) - (sumX * sumX));
                        var intercept = (sumY / len) - ((gradient * sumX) / len);

                        var result = [];
                        for (var j = Math.floor(min); j < Math.ceil(max); j++) {
                            var coordinate = [j, gradient * j + intercept];
                            result.push(coordinate);
                        }`

It works~~