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Dans un courrier daté du 30/10/98 22:16:54 Heure d10iver Pari54 Madrid,
flag@xxxxxxxxxxxx a écrit :
> know that there are many list members smarter than I when it comes to
> programming. So, I hope some one of you could take a moment to explain to
> me why the following code does verify in power editor:
>
> ( 1) plot1(Average((C of Data1/C of Data2),20),"RS");
>
>
> Yet, the code below does not verify in power editor:
>
> (2) plot1(XAverage((C of Data1/C of Data2),20),"RS");
>
>
> nor does this:
>
> (3) RS=XAverage((C of Data1/C of Data2),20);
> (4) plot1(RS,"RS");
>
>
> Statement (1) works fine. Statement (2) produces an error message along the
> lines of, "unresolvable data number". Statements (3) and (4) produce an
> error message along the lines of, "variables and arrays not allowed here".
>
> Clint
Statement (1) works because it' not a recursive calculation.
Statement (2-3-4) do not, because of some internal security check buried into
EL.
If you examin the Xaverage Code, it makes reference to XAverage[1], until the
first bar where Xaverage must be a raw price series (what is not c data1 / c
data2).
inputs : Price(NumericSeries),Length(NumericSimple);
vars : Factor(0);
if Length + 1 <> 0
then begin
if CurrentBar <= 1
then begin
Factor = 2 / (Length + 1);
XAverage = Price; <=======must be a defined serie when using recursive
calculation.
end
else
XAverage = Factor * Price + (1 - Factor) * XAverage[1];
end;
If you want to bypass this, you have to use a diferent version of
Xaverage,that do not refer to Xaverage[1]
if Length + 1 <> 0
then begin
if CurrentBar <= 1
then begin
Factor = 2 / (Length + 1);
XXAverage = Price;
end
else
XXAverage = Factor * Price + (1 - Factor) * XXAverage; <===remember that
XXaverage is in fact XXaverage[1] until the end of the line
end;
As a function cannot refer to itslf, you will need to write:
inputs : Price(NumericSeries),Length(NumericSimple);
vars : Factor(0),xavg0(0);
if Length + 1 <> 0
then begin
if CurrentBar <= 1
then begin
XAvg0 = Price;
end
else
Factor = 2 / (Length + 1);
XAvg0= Factor * Price + (1 - Factor) * XAvg0;
end;
xavg=xavg0;
The next version of EL will be less rstrictive that this one.
Sincerely,
Pierre Orphelin.
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