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Date:	Mon, 12 Mar 2012 13:27:37 -0700
From:	Colin D Bennett <colin AT gibibit DOT com>
To:	geda-user AT delorie DOT com
Subject:	Re: [geda-user] Very confused...possible PCB bug? Need help.
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On Mon, 12 Mar 2012 16:08:28 -0400
Dave McGuire <mcguire AT neurotica DOT com> wrote:

> On 03/12/2012 07:33 AM, Stefan Salewski wrote:
> > The 'divide and conquer' method suggested by gene glick (or
> > going back to a saved backup) is unknown for most windows kids
> > -- I know this when they ask in forums about programming or
> > other problems... The are not able to isolate problems.
> 
>    I like that method, but I was trying to avoid it because this
> board is very nearly done and I need to get a prototype built
> ASAP.

Actually, divide and conquer is often very fast.  It should be
performed like a binary search:

1. Divide in half by deleting everything on the left half of the
board.
2. If the problem remains, recurse into the right half and repeat
by dividing again.
3. Else, if the short has vanished, then undo the delete, delete
the right half instead, and recurse into the left half.
...and so on...

You should find the short in fewer than 10 steps.  Just thank
log2(N) and all the computer science of binary search.

Regards,
Colin

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