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It is easy to understand, if only you READ THE
tutorial section of the guide:
http://www.amibroker.com/guide/h_understandafl.html
All tutorial is must-read.
=================
People are crying for help while in fact
everything you need to read is in the TUTORIAL section
of the guide.
This single short section of the tutorial
http://www.amibroker.com/guide/h_understandafl.html
is absolute must-read and should be read and repeated.
Best regards,
Tomasz Janeczko
amibroker.com
----- Original Message -----
From: "ian_rosbif" <ian_rosbif@xxxxxxxx>
To: <amibroker@xxxxxxxxxxxxxxx>
Sent: Tuesday, November 18, 2008 6:52 PM
Subject: [amibroker] Re: What is wrong with these 3 lines of code?
> You're not dumb, it is rather difficult to understand! Using your
> example and assuming 11 bars in each array:
> Before the 1st statement, auxCrossedIntermed = "00000000000",
> After the 1st statement, auxCrossedIntermed = "00000000010"
>
> Before the 2nd statement, CrossedIntermed = "00000000000",
> and Ref(CrossedIntermed, -1) = "0000000000"... Amibroker effectivley
> treats the Ref... part of the statement as if it was a temporary copy
> of the CrossedIntermed statement taken before the 2nd statement began
> execution (note that there are only 10 elements in this copy array).
> Changes made to CrossIntermed during the 2nd statement by moving
> values from AuxCrossedIntermed are not reflected in the copy array.
> therefore the Ref... clause always copies zero in this scenario.
>
> I hope this clarifies it, but as I said before, the same thing got me
> when I first started out with AB...took me a couple of weeks to
> finally realise what was going on.
>
>
> --- In amibroker@xxxxxxxxxxxxxxx, "nunopires2001" <nunopires2001@xxx>
> wrote:
>>
>> Thanks for the answer.
>>
>> To be honest, i am feeling really dumb, since i didn't understand
> the
>> explanation.
>>
>> Please suppose the following scenario:
>>
>> Low[9]=950
>> Intermed[9]=970
>> High[9]=1000
>>
>> auxCrossedIntermed=IIf(Low< Intermed AND High> Intermed,1,0);
>> CrossedIntermed=auxCrossedIntermed OR Ref(CrossedIntermed,-1);
>>
>> On the bar #10, how will Amibroker evaluate the second formula?
>> During the evaluation, what will be the values for
> auxCrossedIntermed
>> and Ref(CrossedIntermed,-1) ?
>>
>>
>> Best Regards!
>>
>>
>> --- In amibroker@xxxxxxxxxxxxxxx, "ian_rosbif" <ian_rosbif@> wrote:
>> >
>> > Hi,
>> > Are you trying use "...OR Ref(CrossedIntermed,-1);" to get the
> cross
>> > to persist in CrossedIntermed? In other words, if the cross
> occurs at
>> > 11:45, the following 15 elements of Crossintermed should be "1"
> until
>> > 12:01, when they should then all have "666" in them?
>> >
>> > In which case, the problem lies with the "circular" nature of:
>> > >>CrossedIntermed=auxCrossedIntermed OR Ref(CrossedIntermed,-1);
>> >
>> > auxCrossedIntermed will have a combination of 1s & 0s in it, but
>> > these aren't actually "moved" to Crossedintermed until the
> statement
>> > hase been fully evaluated. Therefore Ref(Crossedintermed, -1)
> will
>> > always evaluate to 0 at the time it's executed, even though the 1
>> > appears in the array element representing the cross event after
> the
>> > statement has been executed.
>> >
>> > This is something that drove me mad before I cottoned onto it.
>> > maybe this would work:
>> >
>> > // initialise final values
>> > CrossedIntermed=IIf(TimeNum()>120000, 666, 0);
>> > // set cross events
>> > auxCrossedIntermed=IIf(Low< Intermed AND High> Intermed, 1, 0);
>> > // cross persists for whole day after it occurs once
>> > auxCrossedIntermed = Flip(auxCrossedIntermed, True==False);
>> > // finalise values
>> > CrossedIntermed=IIf(TimeNum()>120000, 666, auxCrossedIntermed);
>> >
>> > If you want the "1" to persist after midday, change the last
>> > statement to:
>> > CrossedIntermed=IIf(auxCrossedIntermed, auxCrossedIntermed,
>> > CrossedIntermed);
>> >
>> >
>> > --- In amibroker@xxxxxxxxxxxxxxx, "nunopires2001"
> <nunopires2001@>
>> > wrote:
>> > >
>> > > Hello,
>> > >
>> > > After a encouraging start with Amibroker, i am realizing that
>> > writing
>> > > code on AFL is not all that simple...
>> > >
>> > > Anyone can explain me what is wrong with these lines of code?
>> > >
>> > > CrossedIntermed=0;
>> > > auxCrossedIntermed=IIf(Low< Intermed AND High>
> Intermed,1,0);
>> > > CrossedIntermed=auxCrossedIntermed OR Ref(CrossedIntermed,-
> 1);
>> > > CrossedIntermed=IIf(TimeNum()>120000,666,CrossedIntermed);
>> > >
>> > > I am working with intraday, 1min data. The market opens at
> 110000
>> > and
>> > > closes at 193000.
>> > >
>> > > I just want to check the CrossedIntermed Value after 12.00h,
> and the
>> > > value returned should be:
>> > > -> 1: If the security crossed Intermed
>> > > -> 0: Otherwise
>> > > -> 666: If TimeNum()>120000
>> > >
>> > >
>> > > Thanks alot!
>> > >
>> >
>>
>
>
>
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