Author: Peter Fendrich
Date: 09:46:30 03/23/04
Go up one level in this thread
On March 23, 2004 at 12:04:35, Uri Blass wrote: >On March 23, 2004 at 11:42:44, Uri Blass wrote: > >>On March 23, 2004 at 10:43:05, Peter Fendrich wrote: >> >>>On March 23, 2004 at 09:13:21, martin fierz wrote: >>> >>>>On March 23, 2004 at 08:59:04, Peter Fendrich wrote: >>>> >>>>>On March 23, 2004 at 04:51:18, Uri Blass wrote: >>>>> >>>>>>On March 23, 2004 at 02:24:38, Tony Werten wrote: >>>>>> >>>>>>>On March 22, 2004 at 19:21:42, Dann Corbit wrote: >>>>>>> >>>>>>>>On March 22, 2004 at 18:57:52, Uri Blass wrote: >>>>>>>> >>>>>>>>>On March 22, 2004 at 18:50:15, Dieter Buerssner wrote: >>>>>>>>> >>>>>>>>>>On March 22, 2004 at 18:16:37, martin fierz wrote: >>>>>>>>>> >>>>>>>>>>>of course i would also like to make an incremental update of that table, but i >>>>>>>>>>>decided against such an attempt because i couldn't figure out how to do it - or >>>>>>>>>>>rather, i devised a scheme for incremental updating which was so horribly >>>>>>>>>>>complicated that i decided not to use it - i'd rather have a slow engine with >>>>>>>>>>>little bugs and good maintainability than a fast engine with many bugs and low >>>>>>>>>>>maintainability :-) >>>>>>>>>> >>>>>>>>>>Reminds me of: >>>>>>>>>> >>>>>>>>>>"Debugging is twice as hard as writing the code in the first place. Therefore, >>>>>>>>>>if you write the code as cleverly as possible, you are, by definition, not smart >>>>>>>>>>enough to debug it." Brian W. Kernighan >>>>>>>>>> >>>>>>>>>>At the moment, I don't use attack tables at all. But I want them again. And I >>>>>>>>>>also only have a "build-from-scratch" routine. I also thought about incremental >>>>>>>>>>updates, and it seems like a very hard job. And the bad thing is, they seem to >>>>>>>>>>be especially useful at the leafs or close to the leafs. Perhaps I will start >>>>>>>>>>again with using them only closer to the root, for pruning/extension decisions. >>>>>>>>>> >>>>>>>>>>Regards, >>>>>>>>>>Dieter >>>>>>>>> >>>>>>>>>I update them incrementally. >>>>>>>>>I can only give a hint that I simply have a function to update incrementally >>>>>>>>>when I add a piece or delete a piece. >>>>>>>>> >>>>>>>>>I got this idea when I got the conclusion that having a function to update them >>>>>>>>>based on a move is a very hard task. >>>>>>>> >>>>>>>>I think I have the same idea: >>>>>>> >>>>>>>You left out the interesting part: >>>>>>> >>>>>>>> >>>>>>>>1. Lift the piece off the board, and remove all of its influence >>>>>>> >>>>>>>1b for every slider attacking the fromsquare, extend its influence >>>>>> >>>>>>You miss the idea >>>>>> >>>>>>All the idea is that I consider no from square and no to square in updating the >>>>>>attack table. >>>>>> >>>>>>I look at a move as a sequence of add piece to square and remove the piece from >>>>>>square and I have function to update the attack table when I add piece or remove >>>>>>piece. >>>>>> >>>>>>Uri >>>>> >>>>>That doesn't change anything. >>>>>When you remove the piece (the piece on the from-square) don't you extend the >>>>>attackers to that piece (1b above) then? >>>>>/Peter >>>> >>>>that seemed to be the big problem in incremental attack updating to me. you have >>>>to remember the attacks for all sliders, and if either the from or the to square >>>>of your move coincides with a slider attack, you have to update the attacks of >>>>this slider. what a bother... >>>> >>>>cheers >>>> martin >>> >>>Yes it is... >>>Basically one need 4 functions: >>>Insert_attacks_from(sq) >>>Remove_attacks_from(sq) >>>Extend_attacks_to(sq) >>>Cut_attacks_to(sq) >>>to be used for different moves. >>>Then there are all the optimistaions that can be done! >>>For instance a capture move to e4 doesn't need the Cut_attacks_to(e4). >>>/Peter >> >>I do it only with 2 functions >>I understand your functions but your from functions is for me only one function >>that addpiece and your to function is one function that delete piece. >> >>With your functions it is possible to look at a capture as doing only 2 of the 4 >>functions so maybe it is better. >> >>Uri > >I looked now at my code and I see that there is a reason for the fact that I do >not have 4 functions. > >For example >When I add a bishop to my board I do not like to do Remove_attacks_from >for diagnols of the bishop because it is a waste of time when I know that I plan >later to add attack information and it is better to change the attack >information for the diagnols of the bishop. > >Uri I don't understand. If you add a bishop to the empty square e4 you would need to run: Insert_attacks_from(e4); Cut_attacks_to(e4); If you remove the bishop you would need: Remove_attacks_from(e4); Extend_attacks_to(e4); Right? Of course you can combine them all to 2 functions by merging Cut... with Remove... and Insert... with Extend.... /Peter
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