trendline.src.js
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/* *
*
* License: www.highcharts.com/license
*
* */
'use strict';
import H from '../parts/Globals.js';
import U from '../parts/Utilities.js';
var isArray = U.isArray;
var seriesType = H.seriesType;
/**
* The Trend line series type.
*
* @private
* @class
* @name Highcharts.seriesTypes.trendline
*
* @augments Highcharts.Series
*/
seriesType(
'trendline',
'sma',
/**
* Trendline (linear regression) fits a straight line to the selected data
* using a method called the Sum Of Least Squares. This series requires the
* `linkedTo` option to be set.
*
* @sample stock/indicators/trendline
* Trendline indicator
*
* @extends plotOptions.sma
* @since 7.1.3
* @product highstock
* @optionparent plotOptions.trendline
*/
{
/**
* @excluding period
*/
params: {
/**
* The point index which indicator calculations will base. For
* example using OHLC data, index=2 means the indicator will be
* calculated using Low values.
*
* @default 3
*/
index: 3
}
},
/**
* @lends Highcharts.Series#
*/
{
nameBase: 'Trendline',
nameComponents: false,
getValues: function (series, params) {
var xVal = series.xData,
yVal = series.yData,
LR = [],
xData = [],
yData = [],
sumX = 0,
sumY = 0,
sumXY = 0,
sumX2 = 0,
xValLength = xVal.length,
index = params.index,
alpha, beta, i, x, y;
// Get sums:
for (i = 0; i < xValLength; i++) {
x = xVal[i];
y = isArray(yVal[i]) ? yVal[i][index] : yVal[i];
sumX += x;
sumY += y;
sumXY += x * y;
sumX2 += x * x;
}
// Get slope and offset:
alpha = (xValLength * sumXY - sumX * sumY) /
(xValLength * sumX2 - sumX * sumX);
if (isNaN(alpha)) {
alpha = 0;
}
beta = (sumY - alpha * sumX) / xValLength;
// Calculate linear regression:
for (i = 0; i < xValLength; i++) {
x = xVal[i];
y = alpha * x + beta;
// Prepare arrays required for getValues() method
LR[i] = [x, y];
xData[i] = x;
yData[i] = y;
}
return {
xData: xData,
yData: yData,
values: LR
};
}
}
);
/**
* A `TrendLine` series. If the [type](#series.trendline.type) option is not
* specified, it is inherited from [chart.type](#chart.type).
*
* @extends series,plotOptions.trendline
* @since 7.1.3
* @product highstock
* @excluding dataParser, dataURL
* @apioption series.trendline
*/