Cannot call previous level

[CPOMorty]

I am trying to create a set of bands that allow me to define a range. I have created a starting point that draws a midband at the middle of the previous bar. What I want to do is draw the band at the same level until the high of the current bar exceeds that level by a certain number of ticks and then the midband will trail the high by that number of ticks, and vice versa for the low.

I am drawing the midband with a function I called calcMB. My challenge has come trying to determine what the value of the midband was on the previous bar. I have tried to call calcMB(-1), MidBand(-1), RangeBands(-1) etc but none of those work. I must be missing something stupid. Any help is appreciated.

There is probably a way to put my code in a box but I could not figure it out.

Thanks,

Murray


var MidBand;
var aRange = new Array();

function preMain() {
setPriceStudy(true);
setStudyTitle("RangeBands");
setShowTitleParameters(false);
setPlotType(PLOTTYPE_LINE, 0);

setCursorLabelName("MidBand", 0); //MidBand
setCursorLabelName("UpperBand", 1); //UpperBand
setCursorLabelName("LowerBand", 2); //LowerBand

setDefaultBarFgColor(Color.RGB(255,0,0), 0); // MidBand
setDefaultBarFgColor(Color.RGB(0,255,0), 1); // UpperBand
setDefaultBarFgColor(Color.RGB(0,255,0), 2); // LowerBand

setDefaultBarStyle(PS_SOLID,0); // MidBand
setDefaultBarStyle(PS_SOLID,1); // UpperBand
setDefaultBarStyle(PS_SOLID,2); // LowerBand

var colBGColor = new FunctionParameter("cColor", FunctionParameter.COLOR);
colBGColor.setName("Range Color")
colBGColor.setDefault(Color.yellow);

var x = 0;
aRange[x] = new FunctionParameter("Range", FunctionParameter.NUMBER);
with(aRange[x++]) {
setLowerLimit(1);
setDefault(10);
}
}

function main(Range,cColor) {

var nDisp = getMinTick() * Range;
MidBand = efsInternal("calcMB");
var UpperBand = MidBand + nDisp
var LowerBand = MidBand - nDisp
setBarBgColor(cColor,0,UpperBand,LowerBand);

return new Array(MidBand, UpperBand, LowerBand);
}

function calcMB() {

var nMid = (high(-1) + low(-1))/2;
/* if (high() - nDisp) > (MidBand(-1) {
nMid = (high() - nDisp);
}
if (high() > high(-1)) {
nMid = high() - nDisp;
}
*/

return nMid;
}

[ACM]

CPOMorty
To call the value of a series object [which is what you created using the efsInternal() function] you use the getValue() method of the Series Object (see this article in the EFS KnowledgeBase) hence Midband.getValue(-1)
As to placing your code in "boxes" use the [PHP] or [CODE] tags (see the Forum FAQ for more information)
Alex

I am trying to create a set of bands that allow me to define a range. I have created a starting point that draws a midband at the middle of the previous bar. What I want to do is draw the band at the same level until the high of the current bar exceeds that level by a certain number of ticks and then the midband will trail the high by that number of ticks, and vice versa for the low.

I am drawing the midband with a function I called calcMB. My challenge has come trying to determine what the value of the midband was on the previous bar. I have tried to call calcMB(-1), MidBand(-1), RangeBands(-1) etc but none of those work. I must be missing something stupid. Any help is appreciated.

There is probably a way to put my code in a box but I could not figure it out.

Thanks,

Murray


var MidBand;
var aRange = new Array();

function preMain() {
setPriceStudy(true);
setStudyTitle("RangeBands");
setShowTitleParameters(false);
setPlotType(PLOTTYPE_LINE, 0);

setCursorLabelName("MidBand", 0); //MidBand
setCursorLabelName("UpperBand", 1); //UpperBand
setCursorLabelName("LowerBand", 2); //LowerBand

setDefaultBarFgColor(Color.RGB(255,0,0), 0); // MidBand
setDefaultBarFgColor(Color.RGB(0,255,0), 1); // UpperBand
setDefaultBarFgColor(Color.RGB(0,255,0), 2); // LowerBand

setDefaultBarStyle(PS_SOLID,0); // MidBand
setDefaultBarStyle(PS_SOLID,1); // UpperBand
setDefaultBarStyle(PS_SOLID,2); // LowerBand

var colBGColor = new FunctionParameter("cColor", FunctionParameter.COLOR);
colBGColor.setName("Range Color")
colBGColor.setDefault(Color.yellow);

var x = 0;
aRange[x] = new FunctionParameter("Range", FunctionParameter.NUMBER);
with(aRange[x++]) {
setLowerLimit(1);
setDefault(10);
}
}

function main(Range,cColor) {

var nDisp = getMinTick() * Range;
MidBand = efsInternal("calcMB");
var UpperBand = MidBand + nDisp
var LowerBand = MidBand - nDisp
setBarBgColor(cColor,0,UpperBand,LowerBand);

return new Array(MidBand, UpperBand, LowerBand);
}

function calcMB() {

var nMid = (high(-1) + low(-1))/2;
/* if (high() - nDisp) > (MidBand(-1) {
nMid = (high() - nDisp);
}
if (high() > high(-1)) {
nMid = high() - nDisp;
}
*/

return nMid;
}

[CPOMorty]

Thanks Alex,

I tried using this in the calcMB function as below and I get an Open Formula Output, the same as my original code gave me. I also tried the same line in the main function planning to pass the value to the calcMB function but there I get a syntax error that MidBand is not defined even though it is declared as a global variable.

Murray


function calcMB() {

var nMidLast = MidBand.getValue(-1);
var nMid = (high(-1) + low(-1))/2;

return nMid;
}

[ACM]

Murray
You cannot pass back to the external function a value that you retrieved from the series you created by calling that same function through esfInternal().
You need to first do your calculations in the external function and if within that function you need a prior value of a variable that is not a series object then you have to retrieve it in a different way and there are several at your disposal. See this thread for examples on how to do this. Also search the forum and you will find numerous other threads on this topic as it has been discussed before
Alex

Thanks Alex,

I tried using this in the calcMB function as below and I get an Open Formula Output, the same as my original code gave me. I also tried the same line in the main function planning to pass the value to the calcMB function but there I get a syntax error that MidBand is not defined even though it is declared as a global variable.

Murray


function calcMB() {

var nMidLast = MidBand.getValue(-1);
var nMid = (high(-1) + low(-1))/2;

return nMid;
}

[CPOMorty]

Hi Alex,

I am using Firefox and Windows 10. Every search I try comes back blank. Is there a secret to using search that I have not found?

Murray

[ACM]

Murray
Use Google (with any browser) to search within the forum eg "previous value" site:forum.esignal.com
That said I have no problems using vBulletin's own forum search in IE11 or Edge
Alex

Hi Alex,

I am using Firefox and Windows 10. Every search I try comes back blank. Is there a secret to using search that I have not found?

Murray

[CPOMorty]

Thanks!

Murray

[ACM]

Murray
You are welcome
Alex

Thanks!

Murray

[CPOMorty]

So I have spent over 2 weeks with 0 progress on this issue. The answers here are cryptic to me. I have printed and read through the EFS guides and read many posts that all seem to be the same without clear answers. I understand that eSignal doesn't support EFS with working code examples any more, but is there anyone who has actually made this work who can share their code with me so I can use it as an example? All I find is pieces that all look fragmented to me. A working indicator that reads its own previous values would be very helpful in my learning how to do this. Are there any indicators posted that I could download and learn from?

Thanks.

[ACM]

CPOMorty
Enclosed below are three basic examples of a script that references its own previous value (note that the script in and of itself serves no purpose other than just being an example)
The first one uses the ref() function (see the EFS KnowledgeBase for more information), the second transfers the values from one variable to another [both of which need to be global] at the first tick of each new bar simply to store its previous value and the third uses an array (again see the EFS KnowledgeBase for more information).
As I said I have explained in several other threads the purpose of each method including limitations (if any) and the reasons for choosing one over another
As to their usage there are literally hundreds of formulas posted in the library or in this forum that will use any of them at some point
Alex

So I have spent over 2 weeks with 0 progress on this issue. The answers here are cryptic to me. I have printed and read through the EFS guides and read many posts that all seem to be the same without clear answers. I understand that eSignal doesn't support EFS with working code examples any more, but is there anyone who has actually made this work who can share their code with me so I can use it as an example? All I find is pieces that all look fragmented to me. A working indicator that reads its own previous values would be very helpful in my learning how to do this. Are there any indicators posted that I could download and learn from?

Thanks.

[CPOMorty]

Working Code

Thanks Alex,

That was very helpful. I now have a working piece of code. For those following my code is below, simple once the nuances are known:

var MidBand = null;
var nMidLast = null;
var aRange = new Array();
var MyVar = 0;

function preMain() {
    setPriceStudy(true);
    setStudyTitle("RangeBands");
    setShowTitleParameters(false);
    setPlotType(PLOTTYPE_LINE, 0);
    
    setCursorLabelName("MidBand", 0); //MidBand
    setCursorLabelName("UpperBand", 1); //UpperBand
    setCursorLabelName("LowerBand", 2); //LowerBand
    
    setDefaultBarFgColor(Color.RGB(255,0,0), 0); // MidBand
    setDefaultBarFgColor(Color.RGB(0,255,0), 1);  // UpperBand
    setDefaultBarFgColor(Color.RGB(0,255,0), 2);  // LowerBand
    
    setDefaultBarStyle(PS_SOLID,0); // MidBand
    setDefaultBarStyle(PS_SOLID,1); // UpperBand
    setDefaultBarStyle(PS_SOLID,2); // LowerBand

var colBGColor = new FunctionParameter("cColor", FunctionParameter.COLOR);
    colBGColor.setName("Range Color")
    colBGColor.setDefault(Color.yellow);
    
var x = 0;
    aRange[x] = new FunctionParameter("Range", FunctionParameter.NUMBER);
    with(aRange[x++]) {
        setLowerLimit(1);
        setDefault(10);
    }
}

function main(Range,cColor) {
    
    if(getCurrentBarCount()<2)
        MidBand=(high()+low())/2;
    if(getBarState()==BARSTATE_NEWBAR)
        nMidLast=MidBand;
    
    var nDisp = getMinTick() * Range;

    if (nMidLast < (high()-nDisp))
        MidBand = (high() - nDisp);
    else if (nMidLast > (low() + nDisp))
        MidBand = (low() + nDisp);


    var UpperBand = MidBand + nDisp;
    var LowerBand = MidBand - nDisp;
    setBarBgColor(cColor,0,UpperBand,LowerBand);

    return new Array(MidBand, UpperBand, LowerBand);
} 

[ACM]

CPOMorty
You are welcome
Alex

Thanks Alex,

That was very helpful. I now have a working piece of code. For those following my code is below, simple once the nuances are known:

var MidBand = null;
var nMidLast = null;
var aRange = new Array();
var MyVar = 0;

function preMain() {
    setPriceStudy(true);
    setStudyTitle("RangeBands");
    setShowTitleParameters(false);
    setPlotType(PLOTTYPE_LINE, 0);
    
    setCursorLabelName("MidBand", 0); //MidBand
    setCursorLabelName("UpperBand", 1); //UpperBand
    setCursorLabelName("LowerBand", 2); //LowerBand
    
    setDefaultBarFgColor(Color.RGB(255,0,0), 0); // MidBand
    setDefaultBarFgColor(Color.RGB(0,255,0), 1);  // UpperBand
    setDefaultBarFgColor(Color.RGB(0,255,0), 2);  // LowerBand
    
    setDefaultBarStyle(PS_SOLID,0); // MidBand
    setDefaultBarStyle(PS_SOLID,1); // UpperBand
    setDefaultBarStyle(PS_SOLID,2); // LowerBand

var colBGColor = new FunctionParameter("cColor", FunctionParameter.COLOR);
    colBGColor.setName("Range Color")
    colBGColor.setDefault(Color.yellow);
    
var x = 0;
    aRange[x] = new FunctionParameter("Range", FunctionParameter.NUMBER);
    with(aRange[x++]) {
        setLowerLimit(1);
        setDefault(10);
    }
}

function main(Range,cColor) {
    
    if(getCurrentBarCount()<2)
        MidBand=(high()+low())/2;
    if(getBarState()==BARSTATE_NEWBAR)
        nMidLast=MidBand;
    
    var nDisp = getMinTick() * Range;

    if (nMidLast < (high()-nDisp))
        MidBand = (high() - nDisp);
    else if (nMidLast > (low() + nDisp))
        MidBand = (low() + nDisp);


    var UpperBand = MidBand + nDisp;
    var LowerBand = MidBand - nDisp;
    setBarBgColor(cColor,0,UpperBand,LowerBand);

    return new Array(MidBand, UpperBand, LowerBand);
}