Difference for efsInternal vs just calling the internal function

[waynecd]

I found I can call an internal function two ways but I am unsure as to what the difference might be.

I can call an internal function by:

var myVar3 = 3.4572894
function main(){
myVar = efsInternal( "rnd", myVar3, 2 );
//or
myVar1 = rnd(myVar3, 2);
debugPrintln(myVar, "myVar- ");
debugPrintln(myVar1, "myVar1- ");
}

function rnd(value, N) { //N = round to N # of digits
var n;
var mult=1;
for(n=0;n<N;n++) mult*=10;
value*=mult;
return Math.round( value,N)/mult;
}


Is the only difference that using efsInternal returns a series and
myVar = rnd(myVar3, 2); just returns the current value?

Thanks in advance.

[ACM]

Re: Difference for efsInternal vs just calling the internal function

waynecd
That is one difference between calling a function directly or through efsInternal(). The other is that by passing inv() or sym() as the last parameter you can control the context in which a function is running ie you can base its calculations on an external interval and/or symbol
Alex

Originally posted by waynecd
I found I can call an internal function two ways but I am unsure as to what the difference might be.

I can call an internal function by:

var myVar3 = 3.4572894
function main(){
myVar = efsInternal( "rnd", myVar3, 2 );
//or
myVar1 = rnd(myVar3, 2);
debugPrintln(myVar, "myVar- ");
debugPrintln(myVar1, "myVar1- ");
}

function rnd(value, N) { //N = round to N # of digits
var n;
var mult=1;
for(n=0;n<N;n++) mult*=10;
value*=mult;
return Math.round( value,N)/mult;
}


Is the only difference that using efsInternal returns a series and
myVar = rnd(myVar3, 2); just returns the current value?

Thanks in advance.

[Guest]

wayncd,

Do not use the efsInternal command to simply call a function, just call it as you did in your second example.

efsInternal creates, in effect, a new global chart environment, using the efs engine to syncronize the two timeframes. A huge waste of resources if not needed, as is the case with your example.

[waynecd]

Thanks stevehare2003, your info will save alot of resources.

I tried both ways to get the slope of the 34 ema into the "function main".
as indicated below, Test 1 - "Returns "null" to output window and freezes eSignal"

and Test 2 "Returns "NaN" to output window and doesn't display 34 ema"

How do I code this?

I intend to use it for several moving avgs so I would like it as a post function. I got it to work if I code it for one mov avg in the "function main".

Thanks in advance.

//**********************Start of Code

var bInit = false;

function preMain() {
setPriceStudy(true);
setStudyTitle("34 EMA Slope");
}
var myStudy3 = null;
var Multi = 10

function main(Multi) {

var myVar3;
if ( bInit == false ) {
myStudy3 = ema( 34 );
bInit = true;
}
myVar3 = myStudy3.getValue(0);
myVar3a = myStudy3.getValue(-1);
/* 1 **************************************///Below returns "null" to output window and freezes eSignal
//vSlope34ema = efsInternal( "_Slope", myVar3,myVar3a,Multi )
//debugPrintln(vSlope34ema.getValue(-1));
/* 1 **************************************///end 1

/* 2 **************************************///Below returns "NaN" to output window and doesn't display 34 ema
vSlope34ema = _Slope(myVar3,myVar3a,Multi)
debugPrintln(vSlope34ema);

/* 2 **************************************///end 2


return new Array( getSeries(myStudy3) );

}

function _Slope(_Point1,_Point2,_Multi){
Slope1 = ((_Point1/_Point2)-1)* _Multi;
angle1 = (Math.atan(Slope1)/(Math.PI/180 ));
// sDisplayPrice1 = Math.round(angle1);
// vCursorSlope1 = " " + Math.round(Slope1);*/
return Slope1;
}
//**********************End of Code

[gspiker]

waynecd,

I made some changes to you code (and commented the changes. It now plots.

Garth

var bInit = false;

function preMain() {
// setPriceStudy(true); I don't think you want this to be a price study....
setStudyTitle("34 EMA Slope");
}
var myStudy3 = null;
var Multi = 10

function main() { // Having main (Multi) overroad your Multi definition above

var myVar3;
if ( bInit == false ) {
myStudy3 = ema( 34 );
bInit = true;
}

myVar3 = myStudy3.getValue(0);
myVar3a = myStudy3.getValue(-1);
/* 1 **************************************///Below returns "null" to output window and freezes eSignal
//vSlope34ema = efsInternal( "_Slope", myVar3,myVar3a,Multi )
//debugPrintln(vSlope34ema.getValue(-1));
/* 1 **************************************///end 1

/* 2 **************************************///Below returns "NaN" to output window and doesn't display 34 ema
vSlope34ema = _Slope(myVar3,myVar3a,Multi)

/* 2 **************************************///end 2


return ( vSlope34ema ); // You don't need to use getValue if you call the function diretly...also don't define the return as an array if it is a single valiable

}

function _Slope(_Point1,_Point2,_Multi){
Slope1 = ((_Point1/_Point2)-1)* _Multi;
angle1 = (Math.atan(Slope1)/(Math.PI/180 ));
// sDisplayPrice1 = Math.round(angle1);
// vCursorSlope1 = " " + Math.round(Slope1);*/
return Slope1;

[kenz987]

///////////////////////////////////////////////////////////////
vSlope34ema = _Slope(myVar3,myVar3a,Multi)
function _Slope(_Point1,_Point2,_Multi){
///////////////////////////////////////////////////////
Programming question: Why use the underscores ( _ ) in the function call? _Point1,_Point2,_Multi
Thanks, Ken

[Guest]

Hi Ken,

From what I have seen, an underscore generally is used to identify a private variable, method or function. Reference this style guide, but it could just as easily be a person's particular style or preference as it is a legal JavaScript identifier.

Originally posted by kenz987
///////////////////////////////////////////////////////////////
vSlope34ema = _Slope(myVar3,myVar3a,Multi)
function _Slope(_Point1,_Point2,_Multi){
///////////////////////////////////////////////////////
Programming question: Why use the underscores ( _ ) in the function call? _Point1,_Point2,_Multi
Thanks, Ken