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MG,
MS is notorius for rounding. Jose's code will show the differences.
{accumulate any x/y event differences}
Cum(x<>y)
I used Cum (x1<>x2)
Since we are looking at differences in the ten thousandths range I'm
not sure it matters a great deal. Usually the differences on the data
that I looked at were only off by .00001
BTW: the Jo kicked in! I'll be up all night.
Preston
--- In equismetastock@xxxxxxxxxxxxxxx, "MG Ferreira" <quant@xxxx>
wrote:
>
> Is it only my MS that rounds in the yellow pop-up box/tooltip
> lookalike giving indicators' values? I also tested it and it
> calculates stuff correctly but, when you keep the mouse hovering
over
> an indicator with more than one value, such as
>
> 1.01;1.02;1.03;1.04;Cum(1)
>
> then a yellow box shows these values, but often rounding them.
>
> Regards
> MG Ferreira
> TsaTsa EOD Programmer and trading model builder
> http://www.ferra4models.com
> http://fun.ferra4models.com
>
>
> --- In equismetastock@xxxxxxxxxxxxxxx, pumrysh <no_reply@xxxx>
wrote:
> >
> > Jose,
> >
> > On
> > x1:=Exp(Sum(Log(y),n)/n);
> > x2:=Exp(Mov(Log(y),n,S));
> > The errors don't occur on every bar but and example is 14.82658
> > versus 14.82657 . So rounded to the thousandths there ain't no
error.
> >
> > On
> > x:=Sum(Cum(1),10)/10;
> > y:=Mov(Cum(1),10,S);
> > There are no errors.
> >
> >
> > Preston
> >
> >
> > --- In equismetastock@xxxxxxxxxxxxxxx, "Jose Silva"
> > <josesilva22@xxxx> wrote:
> > >
> > > Professor MG, my guess is that either you're using one of those
> > funny
> > > copies of MetaStock, or your PC is choking on all those models
you
> > are
> > > running, because I just can't replicate those errors in my
pristine
> > > laboratory environment using the latest geometric protractor
> > > equipment.
> > >
> > > This MS exploration yields zero errors on 1600 stocks with avg
10
> > > years' data:
> > >
> > > ---8<---------------
> > > x:=Sum(Cum(1),10)/10;
> > > y:=Mov(Cum(1),10,S);
> > > { accumulate any x/y event differences }
> > > Cum(x<>y)
> > > ---8<---------------
> > >
> > >
> > > jose '-)
> > > http://www.metastocktools.com
> > >
> > >
> > >
> > > --- In equismetastock@xxxxxxxxxxxxxxx, "MG Ferreira"
<quant@xxxx>
> > > wrote:
> > > >
> > > > Hi Preston & Jose,
> > > >
> > > > Those two formulae for the geometric average should really
give
> > > > exactly the same answer. Unless you work with big numbers and
> > > > loooong averages, the rounding should not affect either
formula
> > > > substantially.
> > > > So I did a quick test. Here is what I entered as a test into
MS
> > > >
> > > > Sum(Cum(1),10)/10;Mov(Cum(1),10,S)
> > > >
> > > > which both calculate a 10 period moving average of Cum(1) =
1, 2,
> > 3,
> > > ...
> > > >
> > > > It calculates this in two ways, one using the sum and one
using
> > the
> > > > Mov function. The first value, for both, should be 5.5
exactly,
> > > > then 6.5, then 7.5 and so on. However, if I do this, I get
two
> > > > lines that appear to be slightly different! If I keep the
pointer
> > > > on this line, to get the two values, I get something like 5.5
> > > > correctly for the first and 5.0, wrong, for the second!
Also, the
> > > > first seems to start at 5.5 and the second, one period later,
at
> > > > 7.0! It yields the same
> > > > incorrect results if you swap it around, say
> > > >
> > > > Mov(Cum(1),10,S);Sum(Cum(1),10)/10
> > > >
> > > > From what I can gather, doing something like
> > > >
> > > > Mov(Cum(1),10,S);Sum(Cum(1),10)/10;1
> > > >
> > > > or funny things like
> > > >
> > > > 1.01;Mov(Cum(1),10,S);Sum(Cum(1),10)/10;1
> > > >
> > > > MS shows the value of the last in the yellow pop-up first,
and it
> > > > seems to round all subsequent (previous!?) values
> > > >
> > > > This bug could be annoying - it seems MS rounds everything
but the
> > > > final value in such an expression containing multiple values.
> > > >
> > > > Regards
> > > > MG Ferreira
> > > > TsaTsa EOD Programmer and trading model builder
> > > > http://www.ferra4models.com
> > > > http://fun.ferra4models.com
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