Accessing arrays returned by efsExternal

[z11]

Hello Alex/Jason/Steve:

I have an efs returns 2 arrays.
In the calling efs I have:

var myVar = efsExternal("xyz.efs", param1);

In xyz.efs :

var array1 = new Array ();
var array2 = new Array ();

return new Array (array1, array2);

Back in calling efs:

var a1 = new Array();
var a2 = new Array();

a1 = getSeries(myVar, 0);
a2 = getSeries(myVar, 1);

but a1, a2 are nulls even though if I run xys.efs as an independent efs, array1 and array2 are filled with correct data.

Please advise. Thank you.

ziggy

[eSignal_JasonK]

Hello ziggy,

EFS does not support multi-dimensional return arrays from main(), which in turn makes efsExternal() limited to single dimensional return arrays from the external EFS. You will have to split your xyz.efs into two separate formulas where each returns a one dimensional array and add a second efsExternal() series in your calling EFS.

[z11]

Thanks for the clarification, Jason.

Is there any mechnism what would handle 2-D arrays? such as efsInternal? efsLibrary?

ziggy

[eSignal_JasonK]

Hello ziggy,

Same problem exists with efsInternal(). It is not designed to accept a multi-dimensional array. With a function library, or any regular user-defined function, you can return a multi-dimensional array. However, as soon as you try to pass that return into the form of a series object you will run into the limitation.

What might work for you is to use a function library to return the multi-dimensional array like below.

test.efsLib

var array1 = new Array (1, 2, 3);
var array2 = new Array (10, 20, 30);

function calc() {
    return new Array(array1, array2);
} 

Then in the calling efs you could split the first dimension of this array back into single dimensional arrays and then convert those into series objects through two efsInternal() calls. The example below is a crude one, but it works.

var myLib = addLibrary("test.efsLib");

function main() {
    var myVar1 = efsInternal("xyz", 0);
    var myVar2 = efsInternal("xyz", 1);
    
    var a1_0 = getSeries(myVar1, 0);
    var a1_1 = getSeries(myVar1, 1);
    var a1_2 = getSeries(myVar1, 2);
    var a2_0 = getSeries(myVar2, 0);
    var a2_1 = getSeries(myVar2, 1);
    var a2_2 = getSeries(myVar2, 2);
    
    return new Array(a1_0, a1_1, a1_2, a2_0, a2_1, a2_2);
}

function xyz(n) {
    var myVar = myLib.calc();
    //debugPrintln(myVar.length);

    return myVar[n];
} 

If the elements in array1 and array2 need to be in the form of series objects, then this function library scenario will not work. You'll have to go with the suggestion of splitting xyz.efs into two formulas. Or you could add an additional parameter to xyz.efs to tell it to return only array1 or array2 so that you are always dealing with a one dimensional return array from xyz.efs.

[z11]

Thanks Jason for these finer points.

1) calling the efs external twice with different parameters so that it knows which array to return sounds like it will work...but won't that create double the overhead? I mean each time you call an efs external, that efs gets loaded...once it returns, does it get "thrown out" of dynamic memory? and it gets loaded again the next time it is called? As for efs internal, that gets loaded once with the calling efs and stays in memory as long as the calling efs is live? and efsLibrary calls would behave the same as efsExternal? Am I correct in my understanding?

2) Just to be sure, in efsExternal:

var a1=new Array (1,2,3);
...
return new Array (a1);

and then in calling efs:

var myVar = efsExternal("xyz.efs", param1);
var v1 = getSeries(myVar, 0).getValue(0);
var v2 = getSeries(myVar, 0).getValue(1);
var v3 = getSeries(myVar, 0).getValue(2);

So v1 = 1?, v2 =2, v3 = 3?

ziggy


ziggy

[eSignal_JasonK]

Hello ziggy,

1) Once you create the series object from an efsExternal() call on the first iteration, that object remains in memory just like it does for efsInternal(). When you make two separate series in your calling efs by calling the same external efs, you will have two series objects in memory. They do not get destroyed and recreated on each iteration of main() in the calling efs. If you want to improve the efficiency of the code a bit, you can make the series object variables global and then initialize them in a bInit or null check routine like below.

var myVar = null;

function main() {
    if (myVar == null) myVar = efsExternal("xyz.efs", param1);

    var v1 = getSeries(myVar, 0);
    var v2 = getSeries(myVar, 1);
    var v3 = getSeries(myVar, 2);

    return new Array(v1, v2, v3);
} 

2) I think your understanding here is correct, but your code example was slightly incorrect. The code example above would be the correct way to reference the elements of the return array where v1 = 1, v2 = 2 and v3 = 3. The code example in my previous post is also a good way to verify this process if you run that code. Below is the calling efs code from my previous post with the bInit routine added.

var myLib = addLibrary("test.efsLib");
var myVar1 = null;
var myVar2 = null;
var bInit = false;

function main() {
    if (bInit == false) {
        myVar1 = efsInternal("xyz", 0);
        myVar2 = efsInternal("xyz", 1);
        bInit = true;
    }

    var a1_0 = getSeries(myVar1, 0);
    var a1_1 = getSeries(myVar1, 1);
    var a1_2 = getSeries(myVar1, 2);
    var a2_0 = getSeries(myVar2, 0);
    var a2_1 = getSeries(myVar2, 1);
    var a2_2 = getSeries(myVar2, 2);
    
    return new Array(a1_0, a1_1, a1_2, a2_0, a2_1, a2_2);
}

var myVar = null;

function xyz(n) {
    if (myVar == null) myVar = myLib.calc();
    //debugPrintln(myVar[1]);
    return myVar[n];
} 

[z11]

Thanks Jason for the further clarification.

I am doing exactly as your sample code is shown whereby I declare a globa var pointing to efsExternal which got assigned within bInit check. I then try to access the elements of returned array as you do in the sample yet I got nulls....I did a debugprint in the efsExternal which showed valid data.

I like to stress that an array object is the single item being returned by efsExternal in such a statement:

return new Array (retArray);

where retArray = (1, 2, 3 .... n)

is that the right way to do it?

ziggy

[eSignal_JasonK]

Hello ziggy,

If retArray is already an array you just need to return that by its self. Give this a try.

return retArray;

The way you are currently are returning the array through new Array(retArray), it is still a two dimensional array where the first dimension is a size of 1, which contains your retArray.

[waynecd]

Hi JasonK and/or anyone who knows,

In your sample below you create two global variables as arrays for the test.efsLib as follows:

var array1 = new Array (1, 2, 3);
var array2 = new Array (10, 20, 30);

function calc() {
    return new Array(array1, array2);
} 

Then you call the test.efsLib via the efsInternal function:

function xyz(n) {
    var myVar = myLib.calc();
    //debugPrintln(myVar.length);

    return myVar[n];
} 

Then from main() you retrieve the two series created in function xyz(n) using:

    if (bInit == false) {
        myVar1 = efsInternal("xyz", 0);
        myVar2 = efsInternal("xyz", 1);
        bInit = true;
    } 

I understand that the 0 and 1 in myVar# = efsInternal("xyz",#) refer to each of the series returned by efsInternal.

As I understand it this is only possible because "function calc()" in test.efsLib doesn't require parameters passed to it since the two arrays are just globals for that efsLib:

var array1 = new Array (1, 2, 3);
var array2 = new Array (10, 20, 30); 

Question: Is there a way to do the same thing but still pass an array such as "hl2()" from the calling efs through the efsInternal to the efsLib and still be able to get the two arrays returned by test.efsLib?

I can't get it to work but something like:

from main()

var mVar1 = efsInternal("TestDual", gamma, vhl2, 0);
var mVar2 = efsInternal("TestDual", gamma, vhl2, 1); 

from efsInternal "TestDual":

function TestDual(vgamma,zhl2,n){

    Fixx = LAGUER.fFilt(vgamma, zhl2);
   return Fixx[n];
} 

to LAGUER1.efsLib:

function fFilt(gamma,xhl2) {
...
    return new Array(Filt, FIR); 

finally plot the returned arrays in main():

    return new Array(getSeries(mVar1), getSeries(mVar2));
//or maybe:
    return new Array(mVar1, mVar2);
//whichever works 

Thanks in advance.

wayne