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Steve,
try
X=MA(C,30);
Y=Flip(X<Ref(X,-1),X>Ref(X,-1));
Buy=Y<Ref(Y,-1);
DT
--- In amibroker@xxxx, "Steve Dugas" <sjdugas@xxxx> wrote:
> Hello All,
>
> I am stuck on what was supposed to be some very simple code, and
grew into a problem. I wonder if someone would be kind enough to
give me some advise. Details are below, but to make a long story
short:
>
> Here is what I am trying to code (simple moving average reversal -
buy when average turns up):
>
> buy = today's MA > yesterday's MA
> AND
> yesterday's MA < MA of most recent day before yesterday whose MA
was not equal to yesterday's
>
> Here is what I have so far:
>
> buy = ma(close,30) > ref(ma(close,30),-1)
> AND
> ref(ma(close,30),-1) < ? (this is the tough part)
>
> Tomasz says that 90% (or whatever) of things can be coded without
using scripts. Can this one be done in AFL? It looks like I need to
iterate the database, right?
>
> OK, here comes the whole sad story for anyone who is interested:
>
> I originally thought this would be very simple to code, and I coded
it as follows:
>
> buy = ma(close,30) > ref(ma(close,30),-1)
> AND
> ref(ma(close,30),-1) < ref(ma(close,30),-2)
>
> After I ran this, and was looking at the resulting trade arrows on
the chart, it was obvious that I was missing some trades (and some
BIG price moves). I did a quick exploration to debug it, which
revealed that (for many stocks, over a long period) there are MANY
instances where the moving average does not change for 2, 3, even 10
or more days in a row. It remains the same right out to 9 decimal
places! One reason for this appears to be that for some stocks, even
though they trade frequently enough now, they would sometimes go for
days without a trade in their early days. There may be other reasons
too, I didnt follow up on all of them. So this brings me to my
current situation - my original simple code only works correctly if
the MA changes every day, which sometimes it doesnt. In order to make
this work properly, I need to look back, day-by-day, starting with
the day-before-yesterday, until I come to a day whose moving average
is different than yesterday's, and then use that days MA in my
formula. Any advise is greatly appreciated. Thanks very much!
>
> Steve
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