Pulsar Chess engine

www.adam16mr.org

Pictures of me

From a FICS finger
1: One of my first computer opponents, back in the early 80ties, was a certain Chess Champion MK I. When I accidentally made an illegal move against it, it simply played on, which gave me the idea to start with 1.Rh1xh8 in the next game. Probably seeing its Ng8 was attacked, it played 1...Nf6 - a blunder, as this allowed 2.Ng1xg7 mate. The champion acknowledged the mate; its window said: LOSE. In the next game, I opened with 1.Bc1xe8, hoping to settle the question of the shortest game forever. But Chess Champion MK I did not comply - it played 1...Qd8xe8, somehow leaving me without a plan. (Tim Krabbe)
Many ask what was my programming background prior to writing pulsar. Well i wrote powerout: http://www.adam16mr.org/powerout97.html
Download

Release September 6 2009
http://www.adam16mr.org/pulsar2009-9b.zip This is an executable only (that means download the pulsar2009-9a release package as well, or you will be comming to me saying why does pulsar always play the same i.e. no books) and fixes a stalemate issue in blitz. no changes to wild programs though shatranj is now included in its variants. You can edit the bad files for 2009-9a to refelct the new engine name. this version of pulsar of pulsar is distributed with winboard in one of the packages.
*important note, liscence terms for pulsar2009-9b.exe*
License conditions:
Pulsar 2009-9b comes "as is", without any guarantees, and using it is entirely at your own risk. It can be freely redistributed in unmodified form, alone or in combination with other software,.
additional: pulsar2009-9b is expected to work with the books from pulsar2009-9a-release package. the liscence also applies to any packaging of pulsar2009-9a.exe or pulsar2009-9b.exe with any combination of books that are wanted to be included from the 9a package or bat files ( with teh name changed to 9b for the 9b package). It is understood do to the number of files someone may only want to package it with books of interest, not all books, or bat files for variants of interest, or just package the exe alone. the release is understood to be the executables, 9a or 9b, and any combination of the books or bat files, or none, which are optional. These liscence conditions may in the future move to another web page within adam16mr.org and be clearly linked on this page for presentation purposes.

Release June 21, 2009
http://www.adam16mr.org/pulsar2009-9a-release.zip pulsar2009-9a-release.zip is under the same liscence ( that is everything in the zip, the exe the books) as pulsar2009-9b. i will restate it here ( posted september 6 2009)
liscence pulsar2009-9a
pulsar2009-9a-release.zip ( which includes pulsar2009-9a.exe its books, and the bat files i made) comes "as is", without any guarantees, and using it is entirely at your own risk. It can be freely redistributed in unmodified form, alone or in combination with other software,.
This release plays normal chess, fischer random, shatranj, 3checks, atomic, crazyhouse, losers, 2kings, suicide/giveaway and shuffle chess all in one program. Also added analysis mode in atomic, losers, giveaway/suicide, crazyhouse, 3checks and regular chess.
I have created some bat files to handicap it at the various variants into 5 levels of difficulty. They are:

http://www.adam16mr.org/pulsar09-atomic-batfiles.zip
http://www.adam16mr.org/pulsar09-3check-batfiles.zip
http://www.adam16mr.org/pulsar09-crazyhouse-batfiles.zip
http://www.adam16mr.org/pulsar09-twokings-batfiles.zip
http://www.adam16mr.org/pulsar09-regular-chess-batfiles.zip
Just extract the bat file into the winboard folder and you can click on one of the files to run pulsar at that variant at that difficulty. The regular pulsar download comes with batfiles to run each variant at full strenght.
note the pulsar2009-9a-release.zip package also has bat files with names like pulsar09-3check.bat, use those to play at full strenght or use analysis mode. Once you start at full strenght go to the winboard mode menu and choose analysis mode or analyze file for anaylsis. You must make the first move while in analysis mode to make pulsar start thinking. Switching from analysis to playing or vice versa not supported.

To play fischer random/chess960 or shatranj, you will need the new winboard: google winboard forum, then go to the discussion room on winboard developement and bug fixing, and the download is the top post.

Older releases
Release June 14, 2007 http://www.adam16mr.org/pulsar2007-9a-release.zip This release plays normal chess, 3checks, atomic, crazyhouse, losers, 2kings, suicide/giveaway and shuffle chess all in one program.
Update March 15, 2009 for windows: engine only. http://www.adam16mr.org/pulsar2007-9a-1.zip. This is an update of the 9a program for those interested in running it on an ics. It fixes two bugs that only impact ics play. One is problems resuming games in atomic and the other is not always using its book. This is not the current program i'm working on in 2009 but a recompile of the original 9a code with those two bugs fixed. 9a has proven so popular I wanted to have a version that was more stable. If you dont play it on an ics, these bugs will never appear to you so you dont need this. I still recommend downloading the original package and then get 9a-1 as the original package has books and bat files, while 9a-1 only has an engine.
I have created some bat files to handicap it at the various variants into 5 levels of difficulty. They are:
http://www.adam16mr.org/pulsar-atomic-batfiles.zip
http://www.adam16mr.org/pulsar-3check-batfiles.zip
http://www.adam16mr.org/pulsar-crazyhouse-batfiles.zip
http://www.adam16mr.org/pulsar-twokings-batfiles.zip
Just extract the bat file into the winboard folder and you can click on one of the files to run pulsar at that variant at that difficulty. The regular pulsar download comes with batfiles to run each variant at full strenght.
None of the bat files work if the bat file and the pulsar download are not extracted or downloaded to the winboard directory which is typically c:\program files\winboard\
Note on handicaping: you can handicap pulsar to only search a certain amount of plys in different variants and normal chess. You need to use a program argument. The program arguments are:
mxA-1 through mxA-5 for atomic searching to ply 1 through 5.
mxT-1 through mxT-5 for 3checks searching to ply 1 through 5.
mxC-1 through mxC-5 for crazyhouse searching to ply 1 through 5.
mxS-1 through mxS-5 for suicide ( like icc giveaway exept you cant castle) searching to ply 1 through 5.
mxL-1 through mxL-5 for losers searching to ply 1 through 5.
mxO-1 through mxO-5 for the chess variants ( includes regular chess, shuffle chess and 2kings) searching to ply 1 to through 5.
to enter a program argument ( i've got downloads for most of the variants with the program argumetn set in the bat file above, just download the bat files to winboard directory and click on them) type instead of: -fcp pulsar2007-9a.exe instead type -fcp "pulsar2007-9a.exe mxA-3" for example to handicap it to play atomic to ply 3. If running on the icc you can use multiple handicaps all listed at once ( whats not handicapped will play at full strenght). For example: -fcp "pulsar2007-9a.exe mxA-3 mxO-3 mxT-4 mxC-2"
To get some more info on how to use the new version of pulsar see:
http://www.adam16mr.org/pulsarscoop2.html
http://www.adam16mr.org/pulsarscoop.html
Linux Versions of pulsar
You can download a 32 bit or 64 bit version of the current pulsar at http://www.adam16mr.org/pulsar/pulsar2007-9b-linux-32
http://www.adam16mr.org/pulsar/pulsar2007-9b-linux-64
I havent had a chance to test these much but the compile seemed to go fine. People who have tried it say it works fine. These linux links are just the executable. You can get the books from the windows pulsar zip file download.
to make pulsar use variants you need to use the xboard '-variant' argument when you start it. You can use both -variant and /variant in winboard. examples:
-variant atomic
-variant crazyhouse
-variant losers
-variant suicide
-variant 3checks
-variant twokings

Pulsar Atomic
You can download the atomic version of pulsar (only plays atomic no other variant) by going to my pulsar-atomic download page. The current version of pulsar atomic is no longer a seperate program from pulsar and can be downloaded above. As of November 15 2006 the source code for atomic-pulsar 2006is available as well.www.adam16mr.org/pulsar-atomic.html
Older versions:
You can download pulsarV2.01g at www.adam16mr.org/pulsarV2.01g.zip
New in 2.01g ( released May 3, 2007) is support for 3checks, fully tested, this 3check code has always been in pulsar just not enabled tell the 2006 release, but that release had a bug were some code that was needed was commented out. Also new in 2.01g is support for a fixed depth seach ( explained below) and the modifiable evaluate has had a bug fixed so it should be working all the time. Also if you click on the pulsarV2.01g.exe executable, it should display the evaluate values its using. It uses M1 - M5 for pawn, knight, bishop, rook, and queen. Be sure to type quit to close the program so it can clear its hash table.
You can download pulsarV2.01f at www.adam16mr.org/pulsarV2.01f.zip
New in 2.01f is support for more time controls like 40 moves in 5 minutes, move now, and a modifiable evaluate.
www.adam16mr.org/pulsarV2.01e.zip
The distributable version plays setboard wilds, 2king or wild 9 on icc and regular chess. Its possible to handicap its time usage and control its hash size with flags after you type the executable name.
Pulsar is a winboard protocol 2 compatible engine. It does not implement the full winboard 2 or winboard 1 protocol. Some features such as analyze mode are currently not available. This version has been tested in winboard and chess partner 5.2.
Winboard can be downloaded at

www.tim-mann.org/chess.html
Arena, another free program that runs winboard compatible engines can be downloaded at

www.playwitharena.com/

Using Winboard
To run a winboard program at home to play against it you typically start winboard with a .bat file. A .bat file is just a text file created in notepad or another text editor. In notepad you have to change from type .txt to type all files before you can create a bat extension. Once you have done that save it for for example as runpulsar.bat. In the text file you place your startup line for the program.
You can create a .bat file to play against pulsar at home with winboard assuming you have downloaded and installed it.
The typical installation path of winboard is c:\program files\winboard\.
To run pulsar at home put: winboard.exe -fcp "pulsarV2.01e.exe" in a .bat file.
Click on the .bat file to run it. If winboard, pulsar, and the .bat file are not all saved in the same directory you will need to supply the exact path for winboard.exe and pulsarV2.01e.exe.
Pulsar2007 plays variants so if your running a variant in home play you need the -variant or /variant option and the variant name which is listed above in the linux download section. only -variant works in linux though. Example:
winboard.exe -fcp pulsar2007-9a.exe -variant atomic
For pulsar2007-9a, if you want to use program argmenmts, described on www.adam16mr.org/pulsarscoop2.html then put the program name with its arguments in quotes. example: winboard.exe -fcp "pulsar2007-9a.exe mxA-3" -variant atomic
To run pulsar on an ics you need some additional flags than just -fcp which stands for first chess program. You will need -zp to tell it to be in zippy mode or automated mode, -ics to tell it to be in internet mode as well as -icshelper and -icshost to tell it to use timestamp or timeseal and to tell it what host to connect to.
Example chessclub.com is a host.
Example:
Winboard.exe -zp -ics -icshost chessclub.com -icshelper timestamp.exe -fcp "pulsarV2.01e.exe"
Information on these and other flags can be found in the winboard help index or help contents.

pulsarV2.01e.exe Engine arguments
See www.adam16mr.org/pulsarscoop2.html for arguments to use with pulsar2007.
Additionally pulsar accepts two flags to handicap its time or hash usage. Enter a number from 100-59,999 to handicap it to game in that many milliseconds. There are 1000 ms in a second. And for older versions you can give it a number 2,4 or 8 to tell it to divide the hash by that amount. tell it 22 or 24 to double or times by 4 the hash. With pulsar2007 the default hash multiplier is 8. Use the 4 argument to cut it in half, the 2 argument to cut it into a 1/4, and the 1 argument to cut it into an 1/8 or the lowest number. Use 16 or 32 to doulbe or times 4 the amount of hash. With a hash multiplier of 8 (the default) is uses about 135 megs of hash. with a multiplier of 1 the whole program uses about 20 megs.
Example:
-fcp "pulsarV2.01e.exe 4 1000"
This would launch pulsar at half the normal hash ( in the 2007 version ) and pulsar will play all its moves in 1000ms. Order doesnt matter.
"pulsarV2.01e.exe 1000 4" is equally valid.
Only one argument or no argument can be used. These arguments can also be used in chess partner. just enter them as part of the program path in engine settings ini file.

fixed depth search
pulsarV2.01g now accepts the argument max-1 through max-4 to limit its max depth to depth 1 to 4.
Examples:
"pulsarV2.01g.exe max-1"
"pulsarV2.01g.exe max-2"

Changing evaluate weights
You can create a file named pulsar.rc for older versions of pulsar or pulsar2.rc for pulsar2007 to tell pulsar how to modify its piece weight values. NOte if you want to make sure that a certain version of pulsar never uses the pulsar.rc file (and you have pulsarV2.01g, the current version, add the program argument "norc" to pulsar.
example:
"pulsarV2.01g.exe norc"
The format of using a pulsar.rc file is as follows.
p + 5
That tells pulsar to add 5/10 to the pawns value. A negative sign can be used to tell pulsar to subtract from the pawns value. p + 5, would make the pawn worth roughly 150. p - 5, would make it worth roughly 50.
Pieces are indicated by p, n, b, r, q. a value will affect both black and white equally.
Additionally use 'x' to tell it to modify the pawn advance point table.
Numbers must be between 1 and 9 and can be indicated as + or -.
Here is a sample pulsar.rc file.
p + 5
n - 1
x + 9

Hit enter after each line including the last line. you can modify as few or as many pieces as you want and order doesnt matter.

Some History

I am just going to write briefly here some historical comments. My first real experience with computer chess was the chess board program fidelity excellence which i purchased for my birthday December 1987 [ see thoughts on chess board computers. ]. I was 17. I played that program at level 1 and could beat it with clever rook mates. But I never could beat it at level 6 or higher.
In 1996 i returned to chess, got a bit better, and could finally beat it at all times under a minute per move. I had done some programming in the meantime. As of yet, I hold no degree in programming, but at the time I had made a arkanoid clone for dos called powerout which I distributed as shareware and a text editor. Click here to download a copy of powerout 2.5 , a vbdos 1 game, and be sure to read the readme.txt for a few useful hints.
In 1997 I bought fritz 4 and in April of 1998 I joined the icc. Shortly thereafter I began to run a crafty account. I was new to internet chess and computer chess seemed like an exciting avenue to pursue. About 2 months after I started my crafty account I decided to write a chess program. This was october 1998.
With help from people on icc's channel 64 most notably kiwipete and diepeveen I got pulsar running on the icc in December and January of 1998/99. It was written in c. The early version did not have a qsearch. It had capture extensions. It only ordered moves by captures and killer moves at the start. Eventually hashing and null move were added and pulsar broke 2200 in the fall of 2000.
In the fall of 2002 I added wild capactiy to pulsar including atomic and 3checks. Atomic has evolved into its own independent program. Now in June 2003 pulsar has been released for the first time.

Pulsar plays under the account 'pulsar' on both fics and the icc chess servers

The World's Most Active Chess Club

www.freechess.org - Free Internet Chess Server