2% band over 10day Simple MA ?

[sgarbs]

Can anyone suggest an easy way to get this coded quickly ?

[ACM]

sgarbs
The Formula Wizard. Attached is the efs created with the FW.
Alex

[sgarbs]

Thanks alex

Many thanks. I just downloaded it and truly appreciate your efforts. Maybe ill get off my feet and figure out how to use the wizard effectively.

[xygeek]

Length = 10;
var avg = new MAStudy(Length, 0, "Close", MAStudy.SIMPLE);

function preMain() {
    setPriceStudy(true);
    setCursorLabelName("top", 0);
    setCursorLabelName("sma", 1);
    setCursorLabelName("bottom", 2);
    setDefaultBarFgColor(Color.red, 0);
    setDefaultBarFgColor(Color.blue, 1);
    setDefaultBarFgColor(Color.green, 2);
}

function main(Length, Percent) {
    if (Length == null) Length = 10;
    if (Percent == null) Percent = 2;
    
    var sma = avg.getValue(MAStudy.MA);
    var top = sma * (1 + Percent * .01);
    var bottom = sma * (1 - Percent * .01);
    
    return new Array(top, sma, bottom);
} 

[sgarbs]

xygeek...

Thanks for helping with that. My question is: If i try to emulate this formula by using the efs wizard - i cant figure out where i would tell it to increase the the 10day ma by 1+2% ?

I only see how to place the 10 day MA , but not add a new 2% band ?

Can this only be done by actually writing the sript ?

[ACM]

sgarbs
In the Formula Wizard use the EnvelopeStudy not the MAStudy.
Alex

[ACM]

xygeek
The way your formula is laid out does not allow for inputs to be passed on to the built-in MA Study. In fact you cannot change the length of the MA via Edit Studies.
You need to modify the formula as follows if you want to be able to use Edit Studies to change the MA Length
Alex

function preMain() {
    setPriceStudy(true);
    setCursorLabelName("top", 0);
    setCursorLabelName("sma", 1);
    setCursorLabelName("bottom", 2);
    setDefaultBarFgColor(Color.red, 0);
    setDefaultBarFgColor(Color.blue, 1);
    setDefaultBarFgColor(Color.green, 2);
}

function main(Length, Percent) {
    if (Length == null) Length = 10;
    if (Percent == null) Percent = 2;
    
    var avg = new MAStudy(Length, 0, "Close", MAStudy.SIMPLE);
    
    var sma = avg.getValue(MAStudy.MA);
    var top = sma * (1 + Percent * .01);
    var bottom = sma * (1 - Percent * .01);
    
    return new Array(top, sma, bottom);
} 

[xygeek]

Thanks! I wasn't aware of that.

[gspiker]

Might I suggest a few changes to Alex's code.

Make the var declaration for the builtin a local global by placing the statement outside of main(). Matt has suggested to me in the past that declaring it inside of main() could cause problems.

Also be sure to initialize it just once for any change in MA length. If it is initialized for every tick you might see crashes at times (I have seen this first hand).

So it would look like:

var avg = null;
var nOldLen = 0;

function preMain() {
    setPriceStudy(true);
    setCursorLabelName("top", 0);
    setCursorLabelName("sma", 1);
    setCursorLabelName("bottom", 2);
    setDefaultBarFgColor(Color.red, 0);
    setDefaultBarFgColor(Color.blue, 1);
    setDefaultBarFgColor(Color.green, 2);
}

function main(Length, Percent) {
    if (Length == null) Length = 10;
    if (Percent == null) Percent = 2;
    
    if (nOldLen == 0 || Length != nOldLen){
        avg = new MAStudy(Length, 0, "Close", MAStudy.SIMPLE);
        nOldLen = Length;
   }
    
    var sma = avg.getValue(MAStudy.MA);
    var top = sma * (1 + Percent * .01);
    var bottom = sma * (1 - Percent * .01);
    
    return new Array(top, sma, bottom);
} 

I believe that keeping the old value of Length and comparing it to
the current length is overkill for this specific example, as changing any of the values via edit study will force eSignal to interate all the bars. This means a simple test for:

if (avg == null)

Would be enough. But I coded it this way so that if people wanted to create an EFS that would allow the Length of the MA to modifed by the EFS dynamically, they would have a template.

Garth

[xygeek]

Thanks, that makes sense. I appreciate the precise syntax you use to refer to things such as local globals. It's helping me understand javascript.

However the input parameters are inaccessible from the edit study menu again. I like the concept of dynamically updating parameters so please let me know if you get it sorted out.

[gspiker]

They are accessible (and even work - just tested) here. If you made ANY changes to the code as posted (including adding comments) either post the changed version here and I will look at it, or remove the changes and see if it works.

G

[xygeek]

Is it possible the lengthy comments made the inputs disappear? It works fine with the comments removed. Here’s the version that didn't work:

/*  Might I suggest a few changes to Alex's code. 

Make the var declaration for the builtin a local global by placing the statement outside of main(). 
Matt has suggested to me in the past that declaring it inside of main() could cause problems.

Also be sure to initialize it just once for any change in MA length. 
If it is initialized for every tick you might see crashes at times (I have seen this first hand).

So it would look like: */


var avg = null;
var nOldLen = 0;

function preMain() {
    setPriceStudy(true);
    setCursorLabelName("top", 0);
    setCursorLabelName("sma", 1);
    setCursorLabelName("bottom", 2);
    setDefaultBarFgColor(Color.red, 0);
    setDefaultBarFgColor(Color.blue, 1);
    setDefaultBarFgColor(Color.green, 2);
}

function main(Length, Percent) {
    if (Length == null) Length = 10;
    if (Percent == null) Percent = 2;
    
    if (nOldLen == 0 || Length != nOldLen){
        avg = new MAStudy(Length, 0, "Close", MAStudy.SIMPLE);
        nOldLen = Length;
   }
    
    var sma = avg.getValue(MAStudy.MA);
    var top = sma * (1 + Percent * .01);
    var bottom = sma * (1 - Percent * .01);
    
    return new Array(top, sma, bottom);
}
 

/*  I believe that keeping the old value of Length and comparing it to 
the current length is overkill for this specific example, 
as changing any of the values via edit study will force eSignal to interate all the bars. 
This means a simple test for:

if (avg == null)

Would be enough. But I coded it this way so that if people wanted to create an EFS that would 
allow the Length of the MA to modifed by the EFS dynamically, they would have a template.

Garth  */ 

[gspiker]

Is it possible the lengthy comments made the inputs disappear?

Heh...if it is the wrong kind of comments.

Make the var declaration for the builtin a local global by placing the statement outside of main(). 

These are the problem lines. Get rid of the paren's after main() (so it is only main and not main()) in both instances. It seems that when they are tokenizing EFS it only looks to match the name main( and doesn't pay attention to comment lines in that case. I got caught by the same thing a short time ago and Matt had to help me figure it out. So you aren't the first to be caught by it.

Garth

[xygeek]

With both EFS applied to the same chart it's easy to see the difference via the edit study menu. The version without comments has inputs while the other one doesn't.

var avg = null;
var nOldLen = 0;

function preMain() {
    setPriceStudy(true);
    setCursorLabelName("top", 0);
    setCursorLabelName("sma", 1);
    setCursorLabelName("bottom", 2);
    setDefaultBarFgColor(Color.red, 0);
    setDefaultBarFgColor(Color.blue, 1);
    setDefaultBarFgColor(Color.green, 2);
}

function main(Length, Percent) {
    if (Length == null) Length = 10;
    if (Percent == null) Percent = 2;
    
    if (nOldLen == 0 || Length != nOldLen){
        avg = new MAStudy(Length, 0, "Close", MAStudy.SIMPLE);
        nOldLen = Length;
   }
    
    var sma = avg.getValue(MAStudy.MA);
    var top = sma * (1 + Percent * .01);
    var bottom = sma * (1 - Percent * .01);
    
    return new Array(top, sma, bottom);
} 

[gspiker]

Hmm...there should have been two lines in the code section that need to be fixed, but for whatever reason only one pasted and now it will not let me edit my own post to fix it (again, for whatever reason).

Anyway these are the lines:


Make the var declaration for the builtin a local global by placing the statement outside of main().
Matt has suggested to me in the past that declaring it inside of main() could cause problems.