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precision IS discussed here, or rather the lack of it in single
precision el compared to double precision in vb. take a course in
numerical analysis and figure it out
TJ
stomping out okie man's ignorance like the grapes of wrath
--- okie madam wrote:
> The question is on precision, not function methodology...
> ----- Original Message -----
> From: The Jackal <tradejacker@xxxxxxxxx>
> To: <omega-list@xxxxxxxxxx>
> Sent: Saturday, June 19, 1999 8:18 PM
> Subject: Re: Easy Language Math Precision
>
>
> > selected messages from a former thread on the very same subject --
> TJ
> >
> > oh yeah, what would be the accumulated error on 1.6 million bar
> with
> > simple average functions in ts? now that boggles the mind even more
> > than okie man's ignorance of such things!!!
> >
> > Resent-Date: Fri, 12 Sep 1997 06:40:00 -0700 (PDT)
> > X-Sender: bfulks@xxxxxxx
> > Date: Fri, 12 Sep 1997 09:29:08 -0400
> > To: Scientific Approaches <sci@xxxxxxxxxx>
> > From: Bob Fulks <bfulks@xxxxxxxxxxx>
> > Subject: Re: EL numerical accuracy
> > Cc: Omega Mailing List <omega-list@xxxxxxxxxxxxxxx>
> > Resent-From: omega-list@xxxxxxxxxx
> > X-Mailing-List: <omega-list@xxxxxxxxxx> archive/latest/9561
> > X-Loop: omega-list@xxxxxxxxxx
> > Resent-Sender: omega-list-request@xxxxxxxxxx
> >
> > >Massimo Ciarafoni wrote:
> > >
> > >> does anyone know which numerical accuracy EL does
> > >> have? I mean how many decimal figures EL uses in
> > >> a result, (i.e. 10/7 equals 1.42, 1.428, 1.4285,
> > >> 1.42857, 1.428571 or ....). Does the price scale
> > >> have any effect on the numerical accuracy?
> > >
> >
> > Several people seemed to question the need for high accuracy in
> > numerical
> > calculations. Obviously, three or four digits of accuracy would
> > normally be
> > satisfactory for the final results. but many operations require
> much
> > greater accuracy than this for intermediate calculations.
> >
> > As a very simple example, the "Average" function supplied with
> > TradeStation
> > calculates the average by subtracting the old bar and adding the
> new
> > bar:
> >
> > Sum = Sum[1] + Price - Price[Length]
> >
> > This is done because it is faster than recalculating everything on
> each
> > new
> > bar.
> >
> > If there were even a small error on each calculation, the total
> error
> > accumulated after hundreds or thousands of bars could be very
> > significant.
> > As it is, the present accuracy is barely adaquate for many
> operations.
> >
> >
> > --
> > Bob Fulks
> > bfulks@xxxxxxxxxxx
> >
> > Resent-Date: Fri, 12 Sep 1997 10:40:40 -0700
> > Date: Fri, 12 Sep 97 10:44:24 PDT
> > From: chris@xxxxxxxx (Chris Norrie)
> > To: omega-list@xxxxxxxxxx
> > Subject: Re: EL numerical accuracy
> > Resent-From: omega-list@xxxxxxxxxx
> > X-Mailing-List: <omega-list@xxxxxxxxxx> archive/latest/9571
> > X-Loop: omega-list@xxxxxxxxxx
> > Resent-Sender: omega-list-request@xxxxxxxxxx
> >
> > Bob make a very good point in the following text. If I understand
> > corectly,
> > TS5 will eliminate the 13,000 bar limit, allowing systems to run on
> a
> > much
> > greater range of data. Accumulating numerical error will become an
> > even
> > greater problem problem unless floating point operands go to either
> 64
> > bits
> > or 80 bits.
> >
> > Chris Norrie
> >
> >
> > --- Mark Brown <markbrown@xxxxxxxxxxxxx> wrote:
> > I think the point is that Easy Language builds up a cumulative
> bunch of
> > errors that anyone of by themselves is not that significant.
> However if
> > you do big jobs and complicated systems that do require precision
> TS
> > just can not do it. The errors will add up to the point to where
> you
> > will be buying where you should be selling. This is the point and
> you
> > know it weather you and PO will admit it or not. If what you say
> is
> > true then what would your interest in Fortran be? Why what would
> be
> > the purpose?
> >
>
>
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