RE: computer-go: Sharing Go modules

["Xu, Mousheng (SEA)" <Mousheng.Xu@xxxxxxxxxxxxxxxxxxxxx>]

Thanks, David.

-- Mo

-----Original Message-----
From: David Fotland [mailto:fotland@xxxxxxxxxxxxxxxxx]
Sent: Wednesday, May 16, 2001 7:20 PM
To: computer-go@xxxxxxxxxxxxxxxxx
Subject: RE: computer-go: Sharing Go modules


At 03:37 PM 5/16/2001 -0700, you wrote:
>Could you explain why a 2D array can cause a performance problem?


Take a look at the assembler output with a debugger.  To get the memory
address for a 2d 19x19 array, there is a multiply by 19.  A one dimensional
array avoids the multiply.  If the computer has index addressing mode, a
single instruction can get the array value.

David


>Thanks.
>
>-- Mousheng Xu
>
>-----Original Message-----
>From: Anders Kierulf [mailto:anders@xxxxxxxxxxxxxxxxx]
>Sent: Wednesday, May 16, 2001 8:33 AM
>To: computer-go@xxxxxxxxxxxxxxxxx
>Subject: RE: computer-go: Sharing Go modules
>
>
> > The coordinate coding method that I use is X,Y converts to X+Y*20. The
> > arrays are all 421 long where all te points at 0,Y and X,0 contain
special
> > values to make it easy to detect the edge of the board. This is a
>convenient
> > coding since it's still fairly easy to see which coordinates they
>represent
> > (for example: 63 is 3,3 and 356 is 16,17). However I do realise that
every
> > Go programmmer has their own idea of how this should be done and that
> > there's little chance that I can convince everyone in the world to use
>this
> > scheme (that would be nice though <grin>) instead of using separate X
and
>Y
> > coordinates.
>
>This is a good scheme. It's the same scheme SmartGo uses, so at least two
Go
>programs have independently reached exactly the same solution. Please go
>ahead and convince the rest of the world. :-)
>
>Anders Kierulf
>www.smartgo.com
>
>
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David Fotland


The information contained in this email is intended for the
personal and confidential use of the addressee only. It may
also be privileged information. If you are not the intended
recipient then you are hereby notified that you have received
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copying of this document is strictly prohibited. If you have
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Group immediately on:

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Celltech Group plc
216 Bath Road, Slough, SL1 4EN, Berkshire, UK

Registered Office as above. Registered in England No. 2159282