RSI_Bands.efs
EFSLibrary - Discussion Board
File Name: RSI_Bands.efs
Description:
These studies are based on the April 2008 article, RSI Bands, by Frangois Bertrand.
Formula Parameters:
- Periods: 14
- Upper Band: 70
- Lower Band: 30
- Band Color: Blue
- Band Thickness: 2
- Enable Clamping: false
Notes:
The related article is copyrighted material. If you are not a subscriber of Stocks & Commodities, please visit www.traders.com.
Download File:
RSI_Bands.efs
EFS Code:
/*********************************
Provided By:
eSignal (Copyright © eSignal), a division of Interactive Data
Corporation. 2007. All rights reserved. This sample eSignal
Formula Script (EFS) is for educational purposes only and may be
modified and saved under a new file name. eSignal is not responsible
for the functionality once modified. eSignal reserves the right
to modify and overwrite this EFS file with each new release.
Description: RSI Bands
by François Bertrand
Version: 1.0 2/5/2008
Notes:
* April 2008 Issue of Stocks and Commodities Magazine
* Study requires version 8.0 or later.
Formula Parameters: Defaults:
Periods 14
Upper Band 70
Lower Band 30
Band Color Blue
Band Thickness 2
Enable Clamping false
**********************************/
function preMain() {
setPriceStudy(true);
setStudyTitle("RSI Bands ");
setCursorLabelName("RSIB70", 0);
setCursorLabelName("RSIB30", 1);
setShowTitleParameters(false);
var fp1 = new FunctionParameter("nPeriods", FunctionParameter.NUMBER);
fp1.setName("Periods");
fp1.setLowerLimit(0);
fp1.setDefault(14);
var fp2 = new FunctionParameter("nUpper", FunctionParameter.NUMBER);
fp2.setName("Upper Band");
fp2.setLowerLimit(0);
fp2.setDefault(70);
var fp3 = new FunctionParameter("nLower", FunctionParameter.NUMBER);
fp3.setName("Lower Band");
fp3.setLowerLimit(0);
fp3.setDefault(30);
var fp4 = new FunctionParameter("cColor", FunctionParameter.COLOR);
fp4.setName("Band Color");
fp4.setDefault(Color.blue);
var fp5 = new FunctionParameter("nThick", FunctionParameter.NUMBER);
fp5.setName("Band Thickness");
fp5.setLowerLimit(1);
fp5.setDefault(2);
var fp6 = new FunctionParameter("bClamp", FunctionParameter.BOOLEAN);
fp6.setName("Enable Clamping");
fp6.setDefault(false);
}
// Global Variables
var bVersion = null; // Version flag
var bInit = false; // Initialization flag
var xUpperRSI = null;
var xLowerRSI = null;
function main(nPeriods, nUpper, nLower, cColor, nThick, bClamp) {
var nState = getBarState();
var nIndex = getCurrentBarIndex();
if (bVersion == null) bVersion = verify();
if (bVersion == false) return;
if (bInit == false) {
setStudyTitle("RSI Bands (" + nPeriods + ", " + nUpper + ", " + nLower + ")");
setCursorLabelName("RSIB"+nUpper, 0);
setCursorLabelName("RSIB"+nLower, 1);
setDefaultBarFgColor(cColor, 0);
setDefaultBarFgColor(cColor, 1);
setDefaultBarThickness(nThick, 0);
setDefaultBarThickness(nThick, 1);
xUpperRSI = efsInternal("RSI_Band", nPeriods, nUpper, bClamp );
xLowerRSI = efsInternal("RSI_Band", nPeriods, nLower, bClamp );
bInit = true;
}
var nUpperRSI = xUpperRSI.getValue(0);
var nLowerRSI = xLowerRSI.getValue(0);
if (nUpperRSI == null || nLowerRSI == null) return;
return new Array(nUpperRSI, nLowerRSI);
}
var result = null;
var result_1 = null;
var P = 0;
var N = 0;
var P_1 = 0;
var N_1 = 0;
function RSI_Band( period, TargetRSILevel, clamp ) {
var diff = null;
var HypotheticalCloseToMatchRSITarget = 0;
var nState = getBarState();
if (nState == BARSTATE_NEWBAR) {
result_1 = result;
P_1 = P;
N_1 = N;
}
if (close(-period) == null) return;
var W = 0;
var S = 0;
var diff = close(0) - close(-1);
if( diff > 0 ) W = diff;
if( diff < 0 ) S = -diff;
// Compute the hypothetical price close to reach the target RSI level
// based on yesterday’s RSI and close
// Depending on if we would need the price to increase or decrease,
// we use a different formula
if (result_1 != null && result_1 > close(-1)) {
HypotheticalCloseToMatchRSITarget = close(-1)+P_1-P_1*period-((N_1*period)-N_1)*TargetRSILevel /(TargetRSILevel - 100);
} else {
HypotheticalCloseToMatchRSITarget = close(-1)-N_1-P_1+N_1*period+P_1*period+(100*P_1)/TargetRSILevel -(100*P_1*period)/TargetRSILevel;
}
if (clamp == true) {
// Optional clamping code
// Enable the clamping option in Edit Studies if parameters used cause too much volatility.
// (generally caused by using a very short period) This will keep the RSI Bands
// within roughly 10% of the price
if ( (HypotheticalCloseToMatchRSITarget - close(-1)) > 0.1*close(-1)) {
HypotheticalCloseToMatchRSITarget = close(-1)*1.1;
} else if ( (HypotheticalCloseToMatchRSITarget - close(-1)) < -0.1*close(-1)) {
HypotheticalCloseToMatchRSITarget = close(-1)*0.9;
}
// Resume standard RSI code to update the running P and N averages
}
P = ( ( period -1 ) * P_1 + W ) / period;
N = ( ( period -1 ) * N_1 + S ) / period;
if (getCurrentBarCount() >= period) {
result = HypotheticalCloseToMatchRSITarget;
return result;
} else {
return null;
}
}
function verify() {
var b = false;
if (getBuildNumber() < 779) {
drawTextAbsolute(5, 35, "This study requires version 8.0 or later.",
Color.white, Color.blue, Text.RELATIVETOBOTTOM|Text.RELATIVETOLEFT|Text.BOLD|Text.LEFT,
null, 13, "error");
drawTextAbsolute(5, 20, "Click HERE to upgrade.@URL=http://www.esignal.com/download/default.asp",
Color.white, Color.blue, Text.RELATIVETOBOTTOM|Text.RELATIVETOLEFT|Text.BOLD|Text.LEFT,
null, 13, "upgrade");
return b;
} else {
b = true;
}
return b;
}