# LinearRegressionCalc.efs

ICE Data Services -

 LinearRegressionCalc.efs

File Name: LinearRegressionCalc.efs

Description:
Example formula for demonstrating the Linear Regression calculations.

Formula Parameters:
nLength: 10

Notes:
The green circles highlight the price series the regression line is based on for visual reference.

 `/*********************************Provided By : eSignal. (c) Copyright 2004*********************************/function preMain() { setPriceStudy(true); setStudyTitle("Linear Regression "); setShowCursorLabel(false); }var aY = null;var c = null;function main(nLength) { var nState = getBarState(); var nIndex = getCurrentBarIndex(); var i = 0; if (nLength == null) nLength = 10; if (aY == null) aY = new Array(nLength); if (nState == BARSTATE_NEWBAR && c != null) { aY.pop(); aY.unshift(c); } c = close(); aY[0] = c; if (nState == BARSTATE_NEWBAR) { if (aY[nLength-1] != null) { i = 1; for (i = 1; i < nLength; ++i) { drawShapeRelative(-i, aY[i], Shape.CIRCLE, null, Color.lime, null, "dot"+i); } } } if (aY[0] != null) { drawShapeRelative(0, aY[0], Shape.CIRCLE, null, Color.lime, null, "dot0"); } // y = Ax + B; // A = SUM( (x-xAVG)*(y-yAVG) ) / SUM( (x-xAVG)^2 ) // A = slope // B = yAVG - (A*xAVG); if (aY[nLength-1] != null) { var xSum = 0; var ySum = 0; i = 0; for (i = 0; i < nLength; ++i) { xSum += i; ySum += aY[i]; } var xAvg = xSum/nLength; var yAvg = ySum/nLength; var aSum1 = 0; var aSum2 = 0; i = 0; for (i = 0; i < nLength; ++i) { aSum1 += (i-xAvg) * (aY[i]-yAvg); aSum2 += (i-xAvg)*(i-xAvg); } var A = (aSum1 / aSum2); var B = yAvg - (A*xAvg); //debugPrintln(nIndex + " Slope: " + -A.toFixed(4) + " Y-intercept: " + B.toFixed(4)); drawLineRelative(0, B, -(nLength-1), (A*(nLength-1)) + B, PS_SOLID, 2, Color.red, "reg"); } return;}`