On Mon, 12 May 2008 08:38:04 +0100, Martin Brown
wrote:

Patrick Volk wrote:
On Fri, 9 May 2008 09:57:41 -0700 (PDT), Sanny
wrote:
Yes, I will see if that can be corrected. It is very difficult to
modify the code as changing one line of code brings new Bugs and then
a week is wasted in correcting the Bugs.

That statement tells me quite at least 2 things:

1) There's a lot of copy and paste in your code (parts tend to look
alike, with minor modifications... some question as to whether making
a change is the right one).

It would make sense to split the code into clean separate modules (even
if there was initially a slight performance penalty).

It is probably well worth profiling it to see exactly where it spends
all its time. Getting the thing to run faster would help a lot. You will
probably find that it spends all its time in the terminal node eval.

C&P is a consequence generally of wandering design. You find some code
that could work, and instead of re-factoring it to fulfill all cases,
you copy and modify it for each.

One of the levels of programming hell (hell not only to maintain, but
to test)!


2) You're probably not using the benefits of Java. Your display might
be OO, but I doubt that your chess analysis part did. What I know
about some contemporary chess engines (the company I work for built
the boards for Deep Blue) is that they evaluate each space.

That is a hardware accelerator tactic which can consider all the squares
using a local sub processor per square. I don't think it works so well
on a PC.

It used at least one processor per square. A PC could thread it, yeah,
not as fast, but it lends itself to replication.


You can score the piece count, but you also can score position...
Simplistically by how many squares are controlled. You only have 3
different kind of squares.

I get the impression it is already a bit better than that, but that
there is something horribly wrong with its quiessence search. Perhaps
because it thinks that pinned pieces can move or something... see the
game with the mobile phone.

Where A-B pruning comes in. At the level it's at, I don't think you're
going to find a queen sacrifice 4 plies down. Bail!


Also I have to agree with what someone else said. For testing
purposes, you really should work on handling position notation. One of
the beauties of chess is the state of the game can store in so few
bytes (64 and be comfortable). If you have a position that is, say, a
mate in 5, you can try that position against different versions (and
load it against different opponents as well).

Regression testing at least means that you can be sure the program still
gets right all the test cases you have tested and fixed so far as well
as any new ones.

Sanny's idea of regression testing is release, and saying how it's
improved 200%.


Checks and draws should be some sort of function... I forget whether
you play a particular sound when the person is in check, but you can
use it for that, and also to put a '+' in the notation (or '#' for
checkmate).

Human readable output needs a couple more tweaks and it would be OK.
Like for example putting the players and dates in the right sort of
brackets and format for standard engines to read.

Its like when we fly Kites. When the threads messup how difficult it
is to correct the jumbeled threads.

This Program is so large that if I have to read whole program line by
line, it will take me full day. So its very difficult to go through
all the codes and correct them.

Bulk spagetti code is not a viable programming model. It is time to
restructure the code and separate the evaluation, move generation and
alpha-beta search into clearly separate modules. Ultimately the majority
of the changes should be in eval once the other components are stable.

Exactly my point. His comments indicate he may not have painted
himself into the corner just yet, but there's probably no doorways or
windows around.
A program isn't philosophically a journey - it's more like a tour.
You have a list of sights to see.


200K isn't that large, even for a one-person project.

It is large if there is no well defined overall structure.

Very true.



Regards,
Martin Brown
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