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Subject: Re: The Brick Wall

Author: Stuart Cracraft

Date: 16:32:26 09/19/04

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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/


Stuart




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