Author: Robert Hyatt
Date: 08:48:46 10/02/00
Go up one level in this thread
On October 01, 2000 at 05:14:42, Mike Adams wrote: >On October 01, 2000 at 04:48:41, Uri Blass wrote: > >>On October 01, 2000 at 04:20:46, Mike Adams wrote: >> >>> I've noticed that pulsar thinks the doubled pawns are worth more than the >>>danger of exposing its castle. When its white and castles kingside this is >>>particular dangerous when it opens the H file especially if the rook is sitting >>>right there on H8. I'm not as concerned about the F and G files because I think >>>it can better defend these files but it can be very difficult to moblize the >>>pieces to defend the H file. Should i put a penalty in at 1.5 times the doubled >>>pawn bonus? >> >>Chess is not a simple game. >>There are cases when open h file is not dangerous inspite of castling in the >>king side and there are cases when open f file is dangerous. >> >>I think that it is impossible to answer your question because the right panelty >>for open file should be dependent in the rest of the evaluation. >> >>Uri > >yes but take a look at this position. pulsar is black and it plays Nxg3. > >[D] r1bq1rk1/ppp2p2/2n4p/3pP1pn/3P4/2P2NB1/P1P1B1PP/R2QK2R b KQ - 0 14 There is more here than worrying about the h-file. Why have you played h6 and g5 when the opponent hasn't castled king-side yet? If he goes the other way, you have self-crucified your position. You have to first teach your program to not advance kingside pawns unless (at least) your opponent has his king on that side as well. In this case, it looks like maybe you chased a bishop and traded a knight for it, while wrecking your kingside totally. So don't worry about Nxg3. Stop the other weakening moves first. > > >I think there are some general rules that you dont open the H file with the >opponents rook on H8. Pulsar does have a king saftey function that tells it not >to advance its castle side pawns but in some positions it seems to like doing >that. Maybe i'm not doing it right i gave it penalties similar to what the >simple chess program does for advancing castled pawns but sometimes when it >advances one pawn I think it gets easier for it to advance another if it thinks >it messes with the opponents postion. That is another area i'll have to look >at. With a check extension and deeper search pulsar, now over 2250 icc blitz, >can get itself out of a lot of diffictulties but some things are just stupid and >in this case i need to build into the evaluate that NxG3 followed by G4 are >really bad. The question is how to do that in a narrow sense that does not give >it rules that are bad half the time. >The move sequence of the game was: .. NxG3 HxG3 G4 Qg2 Gxf3 Qxh6 and of course >its over. Getting it to see Gxf3 is bad is not easy to do. the material value >of the Knight distorts the search and particulary with nullmove its hard to see >at shallower depths like 5 or 6 even with check extensions. I'm trying the >positon at Gxf3 on different versions of pulsar to see how much depth it takes >to see that. So far with NUll move off it does the best and sees it at depth 6. >A freind said he tried it with crafty and crafty had a hard time seeing that >Gxf3 is bad but I did not get to see that for myself. So assuming search is >working which is hard to tell the answer seems to lie in changing the evaluate >in some way that is not to broad but will capture some of the danger of opening >a file as opposed to the double pawn penalty.
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