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Hello,
You need to read User's Guide: Understanding AFL part of the tutorial.
http://www.amibroker.com/guide/h_understandafl.html
It explains that EVERY result of array arithmetic is also an array.
So instead just 1 you have ARRAY of zeros and ones (binary WAVE).
You can visualize such array using Plot:
Plot( c > ref(c, -2), "Binary Wave", colorRed );
BTW:
Ref( C, 2 ) references FUTURE.
Ref( C, -2 ) is correct expression for close two bars ago
Best regards,
Tomasz Janeczko
amibroker.com
----- Original Message -----
From: "ozzyapeman" <zoopfree@xxxxxxxxxxx>
To: <amibroker@xxxxxxxxxxxxxxx>
Sent: Thursday, August 28, 2008 10:20 PM
Subject: [amibroker] Re: The best way to help newbies, oldies, ... and AmiBroker ...
> In keeping with the spirit of this thread then....care to explain this
> one for me (and I suspect, other newbies):
>
> " REF(c>ref(c,2),5); says that the close that happened five days
> ago has to be higher than the close that happened on the sixth day ago. "
>
> My current level of understanding says that this part:
>
> c>ref(c,2)
>
> Will return a 0 or 1. For e.g., if the current close is greater than
> the close of 2 bars ago, this statement is true and therefore "1".
>
> So the longer expression now becomes:
>
> REF(1,5);
>
> Which does not make sense.
>
> I've read the User's Guide. But obviously missed something on how to
> nest a boolean test within the ref function, and have it all make sense.
>
> --- In amibroker@xxxxxxxxxxxxxxx, <professor@xxx> wrote:
>>
>> Ron,
>>
>> The examples that you used were perfect. Even I could understand how
> they worked and learn how to do things that I wanted to do but didn't
> know how to do it. I spent a lot of time using barssince and ref
> trying accomplish this.
>>
>> Thanks,
>> Tom
>> ----- Original Message -----
>> From: Ronald Davis
>> To: amibroker@xxxxxxxxxxxxxxx
>> Sent: Thursday, August 28, 2008 11:36 AM
>> Subject: Re: [amibroker] Re: The best way to help newbies, oldies,
> ... and AmiBroker ...
>>
>>
>> In the very early days of my Amibroker learning curve, The best
> help that I
>> received was from this board when an experienced user was kind
> enough to
>> quickly code an example or what I was asking.
>>
>> Then, I would play with what they had given me, and I started to
> understand
>> how to use Amibroker.
>>
>> For example, REF(c>ref(c,2),5); says that the close that happened
> five days
>> ago has to be higher than the close that happened on the sixth day
> ago.
>>
>> Whereas, SUM(c>ref(c,2),5); only requires that any one or more of the
>> closes over the last five days has to be higher than the previous
> days
>> close.
>>
>> The above examples of simple english explanations from this board
> are how I
>> started learning Amibroker. Ron D
>>
>> ----- Original Message -----
>> From: "Ken Close" <ken45140@xxx>
>> To: <amibroker@xxxxxxxxxxxxxxx>
>> Sent: Thursday, August 28, 2008 12:15 PM
>> Subject: RE: [amibroker] Re: The best way to help newbies, oldies,
> ... and
>> AmiBroker ...
>>
>> > Amen. Amen! AMEN!
>> >
>> > While Tomasz has done so much to improve and expand the
> training/manual
>> > since the early days (he really has!), the fact there is continual
>> > questions
>> > on the same stuff or "small stuff", suggests there is still room
> for and
>> > benefit from improvement.
>> >
>> > I am constantly reminded (or remind myself) that Tomasz has to
> say "Read
>> > the
>> > Manual". Some questions are almost obvious that a quick trip to
> help
>> > would
>> > answer the question, but other "simple" questions are not. Many
> of us do
>> > attempt to find the answers in help but cannot.
>> >
>> > For example, yesterday, I wanted to know how to make subscripted
> arrays.
>> > I
>> > did not remember that VarGet and VarSet was set up to do this.
> So a trip
>> > to
>> > Help and typing in "subscripted arrays" found 9 entries none of
> which led
>> > me
>> > to VarSet or VarGet. I think one of the improvements would be a
> search
>> > system which allowed more complex search logic or strings, or
> some way to
>> > zero in on the specific request. As Tomasz says, it is almost
> always in
>> > there, it just is hard to find.
>> >
>> > Ken
>> >
>> >
>> >
>> > -----Original Message-----
>> > From: amibroker@xxxxxxxxxxxxxxx
> [mailto:amibroker@xxxxxxxxxxxxxxx] On
>> > Behalf
>> > Of Dennis Brown
>> > Sent: Thursday, August 28, 2008 11:58 AM
>> > To: amibroker@xxxxxxxxxxxxxxx
>> > Subject: Re: [amibroker] Re: The best way to help newbies,
> oldies, ... and
>> > AmiBroker ...
>> >
>> > Brian,
>> >
>> > You are correct. I switched to AB because I wanted a programming
> language
>> > that was fundamentally tied into the realtime price arrays and the
>> > charting
>> > for the same. RT quotes --> Database --> AFL -->
>> > Charts. That was all I wanted, and that is pretty much all I use.
>> > There is a lot of overhead associated with getting and
> maintaining the
>> > data,
>> > interacting with the user, and outputting the the data in a
> useful form.
>> > I
>> > only wanted to be concerned with the algorithms that decided to
> buy or
>> > sell.
>> > Interestingly, even with all the support functions handled by
> AB, I still
>> > spend 80% of my time coding UI things! I think it is some kind of
>> > computer
>> > programming law.
>> >
>> > AFL was my real destination with AmiBroker, and I had a hard
> time because
>> > it
>> > was not well defined. A lot of assumptions were made about prior
>> > knowledge
>> > of specific programming language conventions in C like languages.
>> > Languages
>> > I had no experience with. These are middle level languages. My
>> > experience
>> > was with machine level assembler code, and very high level like
>> > Revolution/SuperCard/HyperCard, and a
>> > smattering of BASIC and APL from the original versions 40 years ago.
>> > I had no idea that I was supposed to go learn C syntax before I
> could use
>> > the AFL documentation. IMHO this is a documentation hole big
> enough to
>> > drive a truck through.
>> >
>> > Then what happens when someone has no experience with any
> programming
>> > language at all. Perhaps some Excel experience, or maybe
> experience using
>> > a
>> > programmable calculator. I can't imagine the bewilderment with
> AFL. It
>> > takes a lot of handholding from support or this list to get over
> the first
>> > hump.
>> >
>> > I believe it would be appropriate to define the AFL language in the
>> > documentation as if it were the only language that exists on the
> planet.
>> >
>> > For instance "+" is defined as "Addition". Whereas, in reality
> the "+"
>> > operator is data type dependent. It will add two numbers, add a
> number to
>> > every element in an array, add two arrays element by element, or
>> > concatenate
>> > two strings. It will not add a number or array to a string.
>> >
>> > As I have suggested before, I would have liked to see a "Complete"
>> > listing of all operators, functions, reserved words, syntax
> characters,
>> > directives, etc., in one live list index that points to a page that
>> > explains
>> > each one in the same way that the functions are now described. Then
>> > additional "see also" pointers on those pages to point to more
> in depth
>> > documents when available. In fact the current functions list
> could simply
>> > be expanded to do this.
>> >
>> > This would have saved me many weeks off the learning curve.
>> >
>> > I don't know if Howard is planning on doing this in his new
> book, but it
>> > should be part of the on-line documentation.
>> >
>> > Best regards,
>> > Dennis
>> >
>> >
>> > On Aug 28, 2008, at 10:34 AM, brian_z111 wrote:
>> >
>> >> I didn't explain myself very well there.
>> >>
>> >> What I am saying is that I think we are making it harder by not
>> >> admitting that it is a programmers program and just getting on with
>> >> teaching AFL.
>> >>
>> >> If anyone held told me that at the start I would have run for
> it but
>> >> the fact is that the help manual is about 'AmiBroker the
> program' but
>> >> eventually I came to realise it is all about programming -
>> >> specifically AFL.
>> >>
>> >> So, if I do want to get on with it where do I go?
>> >>
>> >> The AFL section of the help manual is condensed.
>> >> The first few chapters of Howards Book are a basic intro to AB
> and the
>> >> rest of the book is orientated around SystemDesign & Evaluation?
>> >>
>> >> Where is the next stop on the AFL line?
>> >>
>> >>
>> >> brian_z
>> >>
>> >>
>> >>
>> >>
>> >> --- In amibroker@xxxxxxxxxxxxxxx, "brian_z111" <brian_z111@> wrote:
>> >>>
>> >>> Herman,
>> >>>
>> >>>> I always figured that sticking with AFL would have provided a
> more
>> >>>> continuous path for users to develop their programming expertise.
>> >>>
>> >>> This is a new point, not really discussed much before, I think.
>> >>>
>> >>> I really don't know how to put it in words but you are so right.
>> >>>
>> >>> Tomasz should be proud of me because if I am a programmer at all I
>> >> am
>> >>> an array programmer...... but sometimes I am left reaching for
> AFL?
>> >>>
>> >>> Perhaps there are conventions that people with 2 or more
>> >> programming
>> >>> languages automatically understand?
>> >>>
>> >>> Do I have to go and learn C++ as well.
>> >>>
>> >>> Should I need too?
>> >>>
>> >>> brian_z
>> >>>
>> >>
>> >>
>> >>
>> >> ------------------------------------
>> >>
>> >> Please note that this group is for discussion between users only.
>> >>
>> >> To get support from AmiBroker please send an e-mail directly to
>> >> SUPPORT {at} amibroker.com
>> >>
>> >> For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
>> >> http://www.amibroker.com/devlog/
>> >>
>> >> For other support material please check also:
>> >> http://www.amibroker.com/support.html
>> >> Yahoo! Groups Links
>> >>
>> >>
>> >>
>> >
>> >
>> > ------------------------------------
>> >
>> > Please note that this group is for discussion between users only.
>> >
>> > To get support from AmiBroker please send an e-mail directly to
> SUPPORT
>> > {at}
>> > amibroker.com
>> >
>> > For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
>> > http://www.amibroker.com/devlog/
>> >
>> > For other support material please check also:
>> > http://www.amibroker.com/support.html
>> > Yahoo! Groups Links
>> >
>> >
>> >
>> >
>> > ------------------------------------
>> >
>> > Please note that this group is for discussion between users only.
>> >
>> > To get support from AmiBroker please send an e-mail directly to
>> > SUPPORT {at} amibroker.com
>> >
>> > For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
>> > http://www.amibroker.com/devlog/
>> >
>> > For other support material please check also:
>> > http://www.amibroker.com/support.html
>> > Yahoo! Groups Links
>> >
>> >
>> >
>>
>
>
>
> ------------------------------------
>
> Please note that this group is for discussion between users only.
>
> To get support from AmiBroker please send an e-mail directly to
> SUPPORT {at} amibroker.com
>
> For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
> http://www.amibroker.com/devlog/
>
> For other support material please check also:
> http://www.amibroker.com/support.html
> Yahoo! Groups Links
>
>
>
------------------------------------
Please note that this group is for discussion between users only.
To get support from AmiBroker please send an e-mail directly to
SUPPORT {at} amibroker.com
For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
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For other support material please check also:
http://www.amibroker.com/support.html
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