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notice that the first is considered the subtraction
operator - whilst the second is the unitary<FONT face="Times New Roman"
size=3>.
Looks like the math we have always used to
me. Have I missed your point?
Richard
----- Original Message -----
<BLOCKQUOTE
>
<DIV
>From:
dtsokakis
To: <A title=amibroker@xxxxxxxxxx
href="">amibroker@xxxxxxxxxxxxxxx
Sent: Tuesday, April 30, 2002 2:07
AM
Subject: [amibroker] Re: Are your
Composites accurate???
Richard,Note please that in AFL the following results
are true:10-3^2=110+-3^2=19!!!Dimitris Tsokakis--- In <A
href="">amibroker@xxxx..., "Richard Alford" <<A
href="">richard.alford@xxxx...> wrote:> not
in this universe :) It may not, in fact, matter since the
exponentiation operator always (by some other convention?) follows the
operand. Actually the "unitary" is a relatively new term (in the
past 20 years) jumping out after I was well out of grad school (in
mathematical physics) and before the programmers began to worry about
the difference between subtraction and what I always interpreted as a
simple negative number - the computer worries about such things,
people don't. (I do realize the mathematical distinction has been
around for centuries - just ignored like most math in the real world
until it found a use.)> > BTW - Multiplication and division
are not generally on the same level ( My Dear Aunt Sally) for the antiques
in the group; although, when in doubt most simply just hammer in parens by
reflex - similar to the way a horse runs first and asks questions
latter....> > > I still think that this is a simple
documentation error on TJ's part , and,personally, I find that comforting
:)> > Cheers,> > Richard> -----
Original Message ----- > From: Steve Dugas
> To: amibroker@xxxx > Sent: Monday,
April 29, 2002 8:34 PM> Subject: Re: [amibroker] Re: Are
your Composites accurate???> > > It just
occurred to me - maybe they are on the same level (like multiplication and
division), so it does the negation first because it comes to it
first?> > Steve>
----- Original Message ----- > From: Steve
Dugas > To: amibroker@xxxx
> Sent: Monday, April 29, 2002 9:08
PM> Subject: Re: [amibroker] Re: Are your
Composites accurate???> > > Hi
DT,> > I must be missing something.I
tried your plot, and -1^10 did evaluate to 1, like you say. But, if
exponentiation takes precedence over negation (as shown in your table),
how come it doesnt evaluate to -1, like this? :>
> -1^10 = -(1^10) =
-(1) = -1> >
Steve> ----- Original Message -----
> From: dtsokakis
> To: amibroker@xxxx
> Sent: Monday, April 29, 2002
12:16 PM> Subject: [amibroker]Re:
Are your Composites accurate???> >
>
Herman,> I really don´t knowhow do
you realise things.> Well, -1^10 is
equal to 1.> [It acts like (-1)^10
because of priorities in
operators**> [try
Plot(-1^10,"",1,1);]> -1*10^10is a
huge negative number> Another
Amibroker expression is -1e10, also negative
enough.> Your formula was not
correct, because it was excuding stocks with
> open==1 from counting.[see
previous mails to you]>
DT> **Operator precedence and the
parentheses> AFL supports
parentheses in formulas. > >
Parentheses can be used to control the operation precedence (the
> order in which the operatorsare
calculated). AmiBroker always does
> operations within the innermost
parentheses first. When parentheses
> are not used, the precedenceis
as follows (higher precedence listed
> first): >
> No Symbol Meaning
> 1 ^ Exponentiation
> 2 - Negation - Unary minus
> 3 * Multiplication
> 4 / Division
> 5 + Addition
> 6 - Subtraction
> 7 < Less than
> 8 > Greater than
> 9 <= Less than orequal
to > 10 >= Greater than or equal
to > 11 == Equal to
> 12 != Not equal to
> 13 NOT Logical "Not"
> 14 AND Logical "And"
> 15 OR Logical "Or"
> 16 = Variable assignment operator
> > The expression >
> H + L / 2;
> (without parenthesis) would be
calculated by AmiBroker as "L / 2"
> plus "H", since division hasa
higher precedence. This would result
> in a much different value than
> > (H + L)/2; >
> --- In amibroker@xxxx, "Herman
van den Bergen" <psytek@xxxx>
wrote:> > > -----Original
Message-----> > > From:
dtsokakis [mailto:TSOKAKIS@xxxx]>
> > Sent: Sunday, April 28, 2002 11:13
AM> > > To:
amibroker@xxxx> > > Subject:
[amibroker] Re: Are your Composites
accurate???> >
>> >
>> > >
Herman,> > > I just noticed
that your EMPTY is -1^10, ie equal to
1.> > > So, your equivalent
formula is> > > EMPTY =
1;> >
> > Just realized that -1^10 is
not equal to 1 but is -1 * 10^10>
> > > perhaps my code was OK
anyway?> >
> > Take
care,> >
Herman.> >
> >
> >
> >
> > > AddToComposite(IIf(Open
== 1,0,1),"~DataPresent","v",3);>
> > Do you have in the group of your gif some stocks with open==1
?> > > This would give some
explanation.> > >
DT> > > PS The huge negative
symbol in AFL is -1e10> > >
--- In amibroker@xxxx, "dtsokakis" <TSOKAKIS@xxxx>
wrote:> > > > Of course I
receive an identical result list with
your> > > > EMPTY =
-1^10;> > > >
AddToComposite(IIf(Open ==
EMPTY,0,1),"~DataPresent","v",3);>
> > > Buy= 0;> >>
>
f=Foreign("~datapresent","v");>
> > > Filter=f!=101;> >
> > AddColumn(f,"");> >
> > EXACTLY the same
results.> > > > To avoid
any misuderstanding :your formula works, I just
think> > > > Amibroker
does not use the open==EMPTY hypothesis, because if
>
the> > > > ADLAC is not
present on 16/4/2002, there is no reference for
>
ADLAC> > > > this
date.> > > > My opinion is
from experience, Tomasz knows how
AddToComposite()> > >
> works.> > > >
DT> > > > --- In
amibroker@xxxx, "Dimitris Tsokakis" <TSOKAKIS@xxxx>
>
wrote:> > > > > I
respectfully disagree. If you are not concerned about
bar->
by-> > >
bar> > > >
accuracy> > > > > than
you are correct. In that case the "1" method works fine.
>
As> > > > long as
you> > > > > know that
this method will pick up holes of several days but
>
that> > > > it
will> > > > > not pick
up single bar holes.> > >
> >> > > >
>> > > > >
Herman,> > > > > Of
course we speak for daily search,
bar-by-bar.> > > > > I
have in my ^NDX 4 experimental holes
on> > > > > 6/1/2000
[1], 15/2/2000 [1] and 1/3/2000[2]>
> > > > plus the missing ADLAC after
15/4/2002.> > > > > As
you see from the exploration, the
population> > > > > is
different from 101 exactly these
dates.> > > > > I do
not understand the conditions of your
graph.> > > > >
The> > > > >
AddToComposite(1,"~count","v");>
> > > > Buy=0;> >
> > > scans bar-by-bar every stock for each
date.> > > > > If the
stock is present, it adds an 1 and moves to the next
>
stock.> > > > > If
ADLAC is not present on 16/4/2002, then the sum will be
100> > > > > for the
certain date.> > > > >
It is impossible to have a 20% error, there should be
another> > > > >
reason for your results.> >>
> > Dimitris Tsokakis> >
>> >
>> >
>> >
>> >
>> > > Your use of Yahoo!
Groups is subject to > <A
href="">http://docs.yahoo.com/info/terms/>
> >> > >>
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Groups is subject to the Yahoo! Terms of Service. > >
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