2007 Dec: Confirming Price Trend – EFS

R-Squared.efs, LinReg_Slope.efs

File Name: R-Squared.efs, LinReg_Slope.efs

Description:
These studies are based on the December 2007 article, Confirming Price Trend, by Barbara Star PhD.

Formula Parameters:
R-Squared.efs
Periods: 8
Thickness: 2
Color: red
Display: Line
Upper Band: 0.75
Lower Band: 0.20

LinReg_Slope.efs
Periods: 8
Thickness: 2
Color: blue
Display: Line

Notes:
The linear regression formula that was also used in some of the chart images is also included in the formula library. Please see LinearRegressionIndicator.efs. The related article is copyrighted material. If you are not a subscriber of Stocks & Commodities, please visit www.traders.com.

Download File:
R-Squared.efs LinReg_Slope.efs

EFS Code:

R-Squared.efs

/*****************************************************************Provided By : eSignal. (c) Copyright 2004Study:        R-SquaredVersion:      1.011/5/2006Formula Parameters:                 Defaults:    Periods                         8    Thickness                       2    Color                           red    Display                         Line    Upper Band                      0.75    Lower Band                      0.20*****************************************************************/function preMain() {    setStudyTitle("R-Squared ");    setCursorLabelName("R-Squared", 0);    setDefaultBarFgColor(Color.red, 0);    setDefaultBarThickness(2, 0);    setShowTitleParameters(false);        var fp10 = new FunctionParameter("nLRlen", FunctionParameter.NUMBER);        fp10.setName("Periods");        fp10.setLowerLimit(1);        fp10.setDefault(8);        var fp20 = new FunctionParameter("nLRThickness", FunctionParameter.NUMBER);        fp20.setName("Thickness");        fp20.setLowerLimit(1);        fp20.setDefault(2);    var fp30 = new FunctionParameter("nLRColor", FunctionParameter.COLOR);        fp30.setName("Color");        fp30.setDefault(Color.red);    var fp40 = new FunctionParameter("sDisplay", FunctionParameter.STRING);        fp40.setName("Display");        fp40.addOption("Line");        fp40.addOption("Histogram");        fp40.setDefault("Line");    var fp50 = new FunctionParameter("nUpper", FunctionParameter.NUMBER);        fp50.setName("Upper Band");        fp50.setDefault(0.75);    var fp60 = new FunctionParameter("nLower", FunctionParameter.NUMBER);        fp60.setName("Lower Band");        fp60.setDefault(0.2);        }var bInit = false;var xClose = null;var xLinReg = null;function main(nLRlen, nLRThickness, nLRColor, sDisplay, nUpper, nLower) {    if (bInit == false) {        setDefaultBarThickness(nLRThickness, 0);        setDefaultBarFgColor(nLRColor, 0);        if (sDisplay == "Histogram") {            setPlotType(PLOTTYPE_HISTOGRAM, 0);        } else {            setPlotType(PLOTTYPE_LINE, 0);        }        addBand(nUpper, PS_SOLID, 1, Color.blue, "upperBand");        addBand(nLower, PS_SOLID, 1, Color.blue, "lowerBand");        xClose = close();        xLinReg = efsInternal("LinReg", nLRlen, xClose);        bInit = true;    }            if (xLinReg.getValue(0) != null) {        var A = getSeries(xLinReg, 0);  // Slope        var B = getSeries(xLinReg, 1);  // y-intercept        var R = getSeries(xLinReg, 2);  // R-Squared    }        return R;}function LinReg(nLRlen, x) {    if (x.getValue(-nLRlen) == null) return;        var xSum = 0;    var ySum = 0;    var sumXY = 0;    var sumX2 = 0;    var sumY2 = 0;    i = 0;    for (i = 0; i < nLRlen; ++i) {        var xVal = x.getValue(-i);        xSum += (i+1);        ySum += xVal;        sumXY += ((i+1) * xVal);        sumX2 += ((i+1) * (i+1));        sumY2 += (xVal * xVal);    }    var xAvg = xSum/nLRlen;    var yAvg = ySum/nLRlen;    var aSum1 = 0;    var aSum2 = 0;    i = 0;    for (i = 0; i < nLRlen; ++i) {        aSum1 += (i-xAvg) * (x.getValue(-i)-yAvg);         aSum2 += (i-xAvg)*(i-xAvg);    }        //  y = Ax + B;    // A  = SUM( (x-xAVG)*(y-yAVG) ) / SUM( (x-xAVG)^2 )    // A  = slope    // B  = yAVG - (A*xAVG);    // B  = y-intercept    // R2 = r-squared or correlation coefficient        var A = (aSum1 / aSum2);    var B = yAvg - (A*xAvg);        var R2 = Math.pow( (nLRlen * sumXY - xSum * ySum) /          Math.sqrt( (nLRlen*sumX2- (xSum*xSum)) *          (nLRlen*sumY2 - (ySum*ySum)) ) , 2);        return new Array(A, B, R2);}

LinReg_Slope.efs

/*****************************************************************Provided By : eSignal. (c) Copyright 2004Study:        Linear Regression SlopeVersion:      1.011/5/2006Formula Parameters:                 Defaults:    Periods                         8    Thickness                       2    Color                           blue    Display                         Line*****************************************************************/function preMain() {    setStudyTitle("Linear Regression Slope ");    setCursorLabelName("Slope", 0);    setDefaultBarFgColor(Color.blue, 0);    setDefaultBarThickness(2, 0);    setShowTitleParameters(false);        var fp10 = new FunctionParameter("nLRlen", FunctionParameter.NUMBER);        fp10.setName("Periods");        fp10.setLowerLimit(1);        fp10.setDefault(8);        var fp20 = new FunctionParameter("nLRThickness", FunctionParameter.NUMBER);        fp20.setName("Thickness");        fp20.setLowerLimit(1);        fp20.setDefault(2);    var fp30 = new FunctionParameter("nLRColor", FunctionParameter.COLOR);        fp30.setName("Color");        fp30.setDefault(Color.blue);    var fp40 = new FunctionParameter("sDisplay", FunctionParameter.STRING);        fp40.setName("Display");        fp40.addOption("Line");        fp40.addOption("Histogram");        fp40.setDefault("Line");}var bInit = false;var xClose = null;var xLinReg = null;function main(nLRlen, nLRThickness, nLRColor, sDisplay) {    if (bInit == false) {        setDefaultBarThickness(nLRThickness, 0);        setDefaultBarFgColor(nLRColor, 0);        if (sDisplay == "Histogram") {            setPlotType(PLOTTYPE_HISTOGRAM, 0);        } else {            setPlotType(PLOTTYPE_LINE, 0);        }        xClose = close();        xLinReg = efsInternal("LinReg", nLRlen, xClose);        bInit = true;    }            if (xLinReg.getValue(0) != null) {        var A = getSeries(xLinReg, 0);  // Slope        var B = getSeries(xLinReg, 1);  // y-intercept        var R = getSeries(xLinReg, 2);  // R-Squared    }    return A;}function LinReg(nLRlen, x) {    if (x.getValue(-nLRlen) == null) return;        var xSum = 0;    var ySum = 0;    var sumXY = 0;    var sumX2 = 0;    var sumY2 = 0;    i = 0;    for (i = 0; i < nLRlen; ++i) {        var xVal = x.getValue(-i);        xSum += (i+1);        ySum += xVal;        sumXY += ((i+1) * xVal);        sumX2 += ((i+1) * (i+1));        sumY2 += (xVal * xVal);    }    var xAvg = xSum/nLRlen;    var yAvg = ySum/nLRlen;    var aSum1 = 0;    var aSum2 = 0;    i = 0;    for (i = 0; i < nLRlen; ++i) {        aSum1 += (i-xAvg) * (x.getValue(-i)-yAvg);         aSum2 += (i-xAvg)*(i-xAvg);    }        //  y = Ax + B;    // A  = SUM( (x-xAVG)*(y-yAVG) ) / SUM( (x-xAVG)^2 )    // A  = slope    // B  = yAVG - (A*xAVG);    // B  = y-intercept    // R2 = r-squared or correlation coefficient        var A = (aSum1 / aSum2);    var B = yAvg - (A*xAvg);        var R2 = Math.pow( (nLRlen * sumXY - xSum * ySum) /          Math.sqrt( (nLRlen*sumX2- (xSum*xSum)) *          (nLRlen*sumY2 - (ySum*ySum)) ) , 2);        return new Array(-A, B, R2);}