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Subject: Re: The Brick Wall

Author: Andrew Williams

Date: 00:40:05 09/20/04

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On September 19, 2004 at 19:32:26, Stuart Cracraft wrote:

>On September 19, 2004 at 17:49:09, Andrew Williams wrote:
>
>>On September 19, 2004 at 17:28:47, Jon Dart wrote:
>>
>>>On September 19, 2004 at 15:18:47, Andrew Williams wrote:
>>>
>>>>That may be true, but I would reiterate that looking at its performance in WAC
>>>>is not going to help Stuart much in improving it. I don't even think it will
>>>>help much in improving its performance on other tactical tests, but that is just
>>>>a guess. I would strongly re-state my point: to learn what is wrong with a chess
>>>>program, it is better to play games than to test over and over on a test suite.
>>>>Even testing over and over on several test suites is not a good idea, in my
>>>>opinion.
>>>
>>>Test suites have some value. I'd add, that few programs are bug free. Finding
>>>and fixing bugs is beneficial over the long run, even if in the short run such
>>>fixes sometimes actually hurt performance. It is easy to have code that plays
>>>legal chess and even wins games and still have it do horrible wrong things
>>>internally--buffer overruns, memory corruption, you name it. That's why Arasan
>>>has ridiculous amounts of optional debugging and assert checking code. I also
>>>use Bounds Checker.
>>>
>>
>>I'd certainly agree about the use of asserts (PM should have more and I should
>>enable them more often in testing) and Bounds checking (I use valgrind, which is
>>fantastic). I think of those things as finding bugs, rather than improving my
>>program as such. So I wouldn't be looking at how many solutions I got, so much
>>as whether any asserts failed or valgrind saw some problem.
>>
>>I *do* use test sets sometimes (and I like your Arasan suites a lot), but it's
>>more for my amusement than because I think I'm going to learn anything
>>particularly interesting. Perhaps I'm just using them wrong...
>>
>>Andrew
>
>I have zillions of asserts. I used them to do some heavy debugging about
>1/2 of the time ago to the program inception in June. Those plus this board
>got the jump up from about 160 out of 300 on WAC to 250/300.
>
>One of the exponents of program provability and advocate of asserts was
>Bob Floyd at Stanford. He was my initial introduction to programming and
>I remember the strong feelings he had about the subject. Bob has since
>passed on, regrettably, but he left an enormous legacy.
>
>Here for some details:
>
>  http://www.fact-index.com/r/ro/robert_floyd.html
>
>and here for his primary collaborator, Knuth, with thoughts about Bob:
>
>http://sigact.acm.org/floyd/
>
>

I've just read Knuth's appreciation of Floyd in full. Very interesting. Thanks.

Andrew



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