Author: Vincent Diepeveen
Date: 08:29:41 06/05/01
Go up one level in this thread
On June 05, 2001 at 11:14:29, Robert Hyatt wrote:
>>
>>Now see what i get in beowulf. Instead of that in 2001 dudes program
>>better they program things out FOR EVERY PIECE.
>>
>>Even blackpawns and whitepawns are written out.
>>
>>Man such a student i would directly ship back.
>>
>> "Please make the code more general student, if you multiply a 2048 x 2048
>> array you don't write out every multiplication either!".
>>
>>See here below the horror which i found in moves.c from beowulf project.
>>
>>How do you plan to let people learn from this code?
>>
>>They must learn to "write everything out"??
>>
>>Please use a few for loops, even in bitboards you can do that,
>>or have you forgotten how loops work?
>
>Depends on the purpose. "unrolling" is a well-known way to speed up code.
>Compact does not always equal fast. Unrolling also eliminates some tests and
>branches, which is also good.
I know, where did you hear me talk about getting it faster this generator?
Dann Corbitt said this project was setup to let people learn how to write
their own chessprogram and to show how algorithms and implementing
a chessprogram in a nice manner works.
So my comment on this piece of code is that it's not written in a way
where students learn from.
They learn directly how to hack from this: "write everything out".
In this piece of crap code i see everywhere:
if (side == WHITE)
tsq = B->WhiteKnights;
else
tsq = B->BlackKnights;
Note you can eliminate these branches, which speeds code up bigtime.
In a test to generate for white a few million of times a list of moves
the branches will be correctly predicted, but normally spoken you get
a big misprediction there as then you generate for white and next
move for black, that hurts :)
Apart from that it's very ugly to see code like that,
i prefer more compact code to teach students and those who
want to start their own program!
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