scs-ben / pygone Goto Github PK

i just discovered a bug in your code .. here are the concerning lines in pygone.py :

in python (3) the operator '++' (to add one) does NOT exist, in C / CPP it DOES. This is a design decision, see eg. https://www.askpython.com/python/examples/python-increment-operation . However, python3 (or pypy3) gives NO error or warning when using this construct, nothing just happens, the variable will stay the same. Note that played_moves++ WILL give an error.

it seems this little bug does not influence the working of Pygone (v1.5.4) too much, but when you confirm my case, this should be fixed ..

hi, i just discovered your engine .. but i can not compile it on Xubuntu 22.04 :

~/Compiled/pygone/src$ make
pyminifier -o pygone-mini.py pygone.py && bash shrink.sh && python3 combine.py pygone-mini.py > ../bin/pygone && chmod +x ../bin/pygone && gzexe ../bin/pygone && ls -l ../bin/pygone && rm ../bin/pygone~
/bin/sh: 1: pyminifier: not found
make: *** [Makefile:2: pygone] Error 127

i followed your README instructions to build .. it's unclear though : should i edit prepare.sh and THEN do make ?

hi,

didnt know where to post this so sorry for creating an issue..
If you want to prefer shorter mates you can easily change this line

to
return -self.eval_mate_upper + ply

i dont see any ply information yet but this is just the distance from the root, depth might not be accurate because of extensions..

you can then remove this

also this looks very dangerous

while python dictionaries look awesome for a tt, that tt implementation will grow infinitely if im not mistaken...

you can do something like this instead to create a list with a fixed amount of elements

        tt_size = 2**19-1
        transposition_table = [[] for _ in range(tt_size)]

and then you can calculate the index

index = hash % (tt_size - 1)

of course you would need to implement a hashing schema for this first...

additionally I think you are restricting the ttmove too much, you should always search it first if it is a legal move in the position, regardless of pvnode, check or entry depth..

also if the ttmove is < beta you continue to search all other moves but you allow the ttmove to be searched again, just add a continue in your for loop