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Joe,
please excuse if I'm over-whacking the obvious here, but I think you said you
were new to AB, so I wanted to make sure you understood some important
basics.
<SPAN
class=026461604-30122003>
Just
because you can write a formula that directly refers to future data doesn't mean
that that's a valid thing to do. The most obvious example, Ref(array, offset)
can take a negative offset, meaning the number of bars BACK to look,
or a positive offset, meaning the number of bars IN THE FUTURE to look. While
there are situations where it may make sense to do that (pattern analysis etc),
obviously you can't trade signals based on future data, because as good as AB
is, the future bars it would have to look at don't exist yet today, which is
when you need the signal. Systems that peek into the future can backtest
amazingly well (see the Zig function), but can't be traded in real life; it'd be
like looking past the right edge of the chart. There are a bunch of ways to
reference future data in AB, and it's mostly up to you do understand how your
formulas work and avoid it. The Check btn in the backtester will try to warn
you, if it can tell, but understanding is your real tool
here.
<SPAN
class=026461604-30122003>
<SPAN
class=026461604-30122003>Directly referencing future data is fundamentally
different from extrapolating an estimate of it, which at the root of it is what
we're all trying to do -- guess the future by looking at the past. As long as
you don't actually read data from future bars to generate today's indicators,
any way you can think of to make today's decisions is ok. As to how you might do
that, well, that's trading system design (;-).
<SPAN
class=026461604-30122003>
I'm
probably going on and on here explaining the painfully obvious. The point is
just that until you're really confident of your AFL skills and fully understand
the limited situations when it's ok, I'd strongly suggest not referencing
future data, ever.
<SPAN
class=026461604-30122003>
Make
sense?
<SPAN
class=026461604-30122003>
<SPAN
class=026461604-30122003>Dave
<BLOCKQUOTE
>
Dave..
It's certainly interesting that you can write
code for projecting MA's ahead of current price bars....into the future so to
speak.
That makes me think that you might be able
to also project other data into the future as well. What I have in mind
specifically is price data and my interest arises from the fact that the
"projection of price data" into the future and the manipulations that can be
done with it, account in large measure for the development of Jim Hurst's
"Cycle Analysis Program".
Jim Hurst is regarded by many to be the father of
cyclic analysis.
Maybe I could use an example to more clearly show
what I'm driving at.
Suppose you had a printed copy of a daily chart
of say the Nasdaq.....could be anything actually. Then you take an ordinary
drafting room "bow compass" and adjust the points (needle point on one end and
pencil point on the other end) to say 40 days.
Then with the needle point of the compass you
trace over the current price bar centers starting with the last bar
and working backward....simple enough and by keeping the two compass points
horizontal as you trace over the price data with the needle point you also
leave a "line trail" that's made by the pencil point.
That trail is, in effect, a projection
of current daily prices 40 days into the future and that's<FONT
face=Arial size=2> what I would like to be able to convince the computer
to do.
It was not unusual in Hurst's program for several
price projections, of different lengths, to be drawn and shown together in
what he called "cascading patterns".
He called the projections FLD LINES for "future
lines of demarcation" and were the foundation of most of his
work.
His program was detailed in 10, elaborately done,
lessons which could only be described as a labor of love.
I frequently use the bow compass projection
routine but it would be great if there were AB code available that could do
the job.
Does it sound possible?
thanks for listening,
...........Joe Platt
<BLOCKQUOTE
>
----- Original Message -----
<DIV
>From:
Dave Merrill
To: <A title=amibroker@xxxxxxxxxxxxxxx
href="">amibroker@xxxxxxxxxxxxxxx
Sent: Monday, December 29, 2003 11:10
AM
Subject: RE: [amibroker] Shifting
MA's
<SPAN
class=021230616-29122003>ma_shifted = Ref(ma_original,
4);
<SPAN
class=021230616-29122003>
<SPAN
class=021230616-29122003>I'm probably misunderstanding what you're
trying to do, but that makes the average appear 4 bars before the data from
which it was created, looking into the future. Not a tradable
design.
<SPAN
class=021230616-29122003>
<SPAN
class=021230616-29122003>Dave
<BLOCKQUOTE
>How
can I shift a moving average horizontally to the right? I am trying to
move the moving average of the close 4 bars to the right.Thanks in
advance.Bill
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