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Yes, I agree. (Though I would like to see Volume go 64bit in the future.....)
I only have an AMD 850mhz and 512mb of ram......(Currently 256)
As it happens, 256mb of ram failed on good friday (Real good!!!!)
(Which incidently Trashed my entire Windows Partition and My
Apps Partition - Causing me to loose ALL my trading stuff.)
Luckily I had done a backup to CD only 4 days prior.
Anyway to get to the point........ I have Noticed a DEFINITE performance
hit running 256mb of ram opposed to 512mb ram. (I also run Seti in the
Background).
All the best,
Michael.
At 06:46 PM 17/04/2004, you wrote:
>Hello,
>
>Some of us still do not have "couple of GB" of RAM :-)
>(Myself I have only 512MB in my main computer and 192MB on notebook)
>
>Best regards,
>Tomasz Janeczko
>amibroker.com
>----- Original Message -----
>From: "qqqqq_99999_qqqqq" <qqqqq_99999_qqqqq@xxxxxxxxx>
>To: <amibroker@xxxxxxxxxxxxxxx>
>Sent: Saturday, April 17, 2004 1:04 AM
>Subject: [amibroker] Re: double (64-bit) precision
>
>
> > Thank you for the detailed answer.
> >
> > I just thought a 5,000-symbol portfolio with 20-year daily data on a
> > couple of GB of RAM was *practical*...
> >
> > regards,
> > ysk
> >
> > --- In amibroker@xxxxxxxxxxxxxxx, "Tomasz Janeczko" <amibroker@xxxx>
> > wrote:
> > > Hello,
> > >
> > > 1. Not easy but doable. Problem is with the existing plugins - they
> > would ALL need to be rewritten.
> > >
> > > 2. Raw calculation speed is not a problem because calculations are
> > processed anyway using FPU which is almost
> > > as fast in 32 bit IEEE as in 64 bit IEE. The problem is the
> > MEMORY and accessing 2x larger data blocks.
> > >
> > > Note that internal calculations and intermediate result storage
> > are 64 bit already but just results
> > > and data fields are stored in 32 bit floating point format. And
> > this is mainly to conserve memory usage.
> > > Eventual speed drop would be the result of 2x memory size
> > required (for example: things that fit into CPU cache
> > > would not fit anymore - if data do not fit into the cache it
> > means HUGE drop in performance).
> > >
> > > 64 bit precision means DOUBLING memory requirements.
> > > It may not be a problem for you but several people are trying to
> > calculate things on 500000 data bars.
> > > Currently each such array consists of 4MB. Quote data (OHLCVOI -
> > 6 * 8 * 500000 bytes = 24MB).
> > > This means that 500000 bars of single security would take 24MB of
> > CONTINUOUS memory.
> > > This becomes a problem because on Windows RAM is very often
> > fragmented and even if you have for example
> > > 128MB ram free there is no 24MB continuous block.
> > > Also when running portfolio backtests memory is required to hold
> > entry/exit prices and if this would need
> > > to be in 64 bit then people running backtests on large portfolios
> > (>1000 symbols) would not be able to
> > > run them at all.
> > >
> > > Frankly from my point of view it does not make any sense. 32 bit
> > floating point provides accuracy of
> > > 1e-7 it is: 0.00001%.
> > >
> > > I simply can not imagine how anyone would consider 0.000001%
> > accuracy inappropriate for financial
> > > application. If you are trading say portfolio worth $100000 (one
> > hundred thousands dollars) 32bit floating point provides results
> > > that are accurate +/- $0.01 (plus/minus one cent). Practical
> > accuracy is better because INTERMEDIATE
> > > calculations and results in backtester are performed in full 64 bit
> > so total profit and other reported figures are
> > > much more accurate (upto 15 significant digits)
> > >
> > > This is why I don't think if moving everything to 64 bit has ANY
> > *practical* merrit.
> > >
> > > Best regards,
> > > Tomasz Janeczko
> > > amibroker.com
> > > ----- Original Message -----
> > > From: "qqqqq_99999_qqqqq" <qqqqq_99999_qqqqq@xxxx>
> > > To: <amibroker@xxxxxxxxxxxxxxx>
> > > Sent: Friday, April 16, 2004 6:12 PM
> > > Subject: [amibroker] double (64-bit) precision
> > >
> > >
> > > > Tomasz,
> > > >
> > > > 1) How easy is it to convert AmiBroker to double (64-bit)
> > precision ?
> > > >
> > > > 2) How much sacrifice in terms of speed do you expect from the
> > > > conversion?
> > > >
> > > > TIA
> > > >
> > > > regards,
> > > > ysk
> > > >
> > > >
> > > >
> > > >
> > > > Send BUG REPORTS to bugs@xxxx
> > > > Send SUGGESTIONS to suggest@xxxx
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> > > > Post AmiQuote-related messages ONLY to: amiquote@xxxxxxxxxxxxxxx
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> > > > --------------------------------------------
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> > > > Yahoo! Groups Links
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> >
> >
> >
> >
> > Send BUG REPORTS to bugs@xxxxxxxxxxxxx
> > Send SUGGESTIONS to suggest@xxxxxxxxxxxxx
> > -----------------------------------------
> > Post AmiQuote-related messages ONLY to: amiquote@xxxxxxxxxxxxxxx
> > (Web page: http://groups.yahoo.com/group/amiquote/messages/)
> > --------------------------------------------
> > Check group FAQ at:
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> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
>
>
>
>Send BUG REPORTS to bugs@xxxxxxxxxxxxx
>Send SUGGESTIONS to suggest@xxxxxxxxxxxxx
>-----------------------------------------
>Post AmiQuote-related messages ONLY to: amiquote@xxxxxxxxxxxxxxx
>(Web page: http://groups.yahoo.com/group/amiquote/messages/)
>--------------------------------------------
>Check group FAQ at:
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>Yahoo! Groups Links
>
>
>
>
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