Search found 19 matches

by steffan
Fri Apr 05, 2013 8:49 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: How to Shift Left a Negative Number??
Replies: 31
Views: 7740

Re: How to Shift Left a Negative Number??

Rotate the bits rather than shifting them. For 64 bit quantities, a rotation by 8 bits in one direction is the same as rotation by 56 bits in the other direction.

Cheers,
Steffan
by steffan
Sun Mar 20, 2011 10:59 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Possible Board Presentation and Move Generation for GPUs?
Replies: 14
Views: 3947

Re: Possible Board Presentation and Move Generation for GPUs

Dear Chess Programmers, i still try to get a prototype of a chess engine running on a GPU and i am stuck with the first things like Board Presentation and Move Generation. Maybe you got an idea to help me out? Technic background: GPUs act as a SIMD device with many threads/processors and compute da...
by steffan
Thu Nov 05, 2009 4:05 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Problem with functions not inlining
Replies: 31
Views: 4935

Re: Problem with functions not inlining

Are you certain your project settings are set for "release" rather than "debug"? From what I remember of Visual Studio, debug effectively turns off optimisations, including inlining.
by steffan
Tue Aug 11, 2009 7:47 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Bit twiddling question, part 2: arbitrary bitscan order
Replies: 14
Views: 3039

Re: Bit twiddling question, part 2: arbitrary bitscan order

Zach Wegner wrote:... At the end we have the highest existing priority 0<=p<=63 in result, which we use in a reverse lookup table.
Why do the lookup? By the end of your code, isn't the answer in the variable bb? If so, you dont need the 'result' variable at all.

Cheers,
Steffan
by steffan
Mon Jun 22, 2009 7:58 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: On Zobrist keys
Replies: 10
Views: 3697

Re: On Zobrist keys

I wonder whether random base keys or De Bruin sequences work better. I think the ideal keys have on average half their bits set, and all bits are mutually independent. Random keys satisfy both criteria, but de Bruijn keys fail the independence criterion : For example, all de Bruijn sequences have e...
by steffan
Mon Jun 22, 2009 8:37 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: On Zobrist keys
Replies: 10
Views: 3697

Re: On Zobrist keys

I too have had success using rotated Zobrist keys. As an experiment (a long time ago!) I modified Crafty to use rotated keys and had no collisions in the small number of self-play games I tried.

Cheers,
Steffan
by steffan
Mon Jun 08, 2009 8:53 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Need a tool to compare two C-source files
Replies: 20
Views: 4280

Re: Need a tool to compare two C-source files

Eclipse has a 2-way (and 3-way) graphical diff and merge capability for text files. It can also perform recursive directory compares. Comparisons can be performed between any files or directories in the workspace, or any historical versions stored either by Eclipse ("local history") or your choice ...
by steffan
Thu Jun 04, 2009 11:00 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Need a tool to compare two C-source files
Replies: 20
Views: 4280

Re: Need a tool to compare two C-source files

Eclipse has a 2-way (and 3-way) graphical diff and merge capability for text files. It can also perform recursive directory compares. Comparisons can be performed between any files or directories in the workspace, or any historical versions stored either by Eclipse ("local history") or your choice ...
by steffan
Wed Apr 08, 2009 10:37 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Tool to manage programming task, ideas, tests, etc
Replies: 9
Views: 2218

Re: Tool to manage programming task, ideas, tests, etc

For managing ideas and concepts, a mind mapping tool like FreeMind can be useful.

Cheers,
Steffan
by steffan
Fri Mar 13, 2009 11:26 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Simple self test code
Replies: 8
Views: 1733

Re: Simple self test code

Testing the correctness of an implementation can actually speed up the programming process rather than slow it down, as this affords the programmer greater confidence that incorrect changes will be quickly flagged. Writing unit tests is one way (of several) of testing correctness that gives you very...