I have released new version of Scorpio 2.8. The major change is that ScorpioMCTS is now greatly improved thanks to alpha-beta rollouts. From the readme:
MCTS
The montecarlo tree search engine uses alpha-beta rollouts according to Huang paper. This is much stronger than standard MCTS in games like chess which ar full of tactics. ScorpioMCTS storing all the tree in memory has become very close in strength to the standard alpha-beta searcher due to alpha-beta rollouts. It can actually become same strength as the standard if we limit the amount of tree stored in memory via "treeht" parameter in the scorpio.in. When the MCTS search runs out memory, it will spawn standard recursive alpha-beta search at the leaves so setting treeht = 0 stores only root node and its children, effectively becoming same strength as the standard alpha-beta method. If we set treeht = 128 MB, upper parts of the tree will be stored in memory and MCTS used there. Note that 128MB of memory are not allocated immediately at start up; it only specifies the maximum memory to use for storing tree. Don't forget to set montecarlo=1 if you want to experiment with MCTS.
Code: Select all
##################################################################
# montecarlo - Use montecarlo tree search (MCTS) if set to 1
# treeht - Maximum size of tree to store in memory given in MB.
# Note that this memory is not allocated at start up; it only
# specifies the maximum limit the tree could grow to.
# Note: Don't think you are making scorpio weak by not setting
# this memory to high value, infact treeht=0 is the strongest
# MCTS setting.
##################################################################
montecarlo 0
treeht 128
Standard
The standard search is also improved (which btw is still the default) with regard to search parameters tuning with CLOP, fixing ABDADA bug, turning on singular extensions etc. No evaluation changes, but I plan to couple Leela Chess neural nets with ScorpioMCTS if I can find someone to work with me.
regards,
Daniel