Author: blass uri
Date: 11:16:27 06/30/98
Go up one level in this thread
On June 30, 1998 at 12:13:50, Komputer Korner wrote: >On June 29, 1998 at 14:17:55, blass uri wrote: > >>On June 29, 1998 at 13:55:30, Komputer Korner wrote: >> >>>On June 29, 1998 at 11:07:13, blass uri wrote: >>> >>>>Fritz5 has a function of correspondence analysis. >>>>with this function Fritz5 generates a detailed analysis tree for a position. >>>>I can decide how deep and broad the resulting tree should get and what >>>>moves should be included or excluded from the analysis. >>>> >>>>in order to use the fritz5 correspondence analysis I give fritz5 some numbers: >>>>1)time per move(it is time per node in the tree and it is not a good idea >>>>because I want to give the computer more time to analyze the nodes near the root >>>>because it is more important not to do a mistake in analysis near the root I >>>>think the possibility to choose time per ply 1,time per ply 2,... is a better >>>>idea) >>>> >>>>2)Branching:The branching factors for the 1st,2nd and 3rd moves define >>>>how many alternative moves are given in the first ply,second ply and third ply >>>> >>>>3)Length of variation:This sets the length of analysed variations >>>> >>>>4)Evaluation window:This value ,given in 100ths of pawns,determine when >>>>Fritz will discard a variation. If you set the value to 80, for instance, >>>>then moves which are 0.8 pawns worse than the best move will not be investigated >>>>any further-even if the branching factor would allow it. >>>> >>>>The main problem with the tree fritz5 generates is the fact fritz5 >>>>analyses illogical lines >>>> >>>>for example suppose the branching factors are 2 for the 1st ply 2 for the >>>>second ply and 1 for the third ply >>>>and the length of variation is 3 >>>>and the time number is 60 seconds per move >>>> >>>>Fritz5 can do the following tree >>>>it is only an example(fritz5 did not generate this tree but generates trees >>>>with the same mistake) >>>> >>>>line 1:1.e4 e5 Nf3 0.1 pawns for white >>>>line 2:1.e4 c5 Nf3 0.2 pawns for white >>>>line 3:1.d4 Nf6 c4 0.08 pawns for white >>>>line 4:1.d4 d5 2.Nf3 0.04 pawns for white. >>>> >>>>near 1 minute for finding 1.e4 and 1.d4 the two best moves. >>>>near 1 minute for finding 1...e5 and 1...c5(2 best replies to 1.e4) >>>>near 1 minute for finding 1...Nf6 and 1...d5(2 best replies to 1.d4) >>>>near 4 minute for finding the third ply in lines 1,2,3,4(1 minute for a line) >>>> >>>>I do not need the last line to understand 1.e4 is better than 1.d4 >>>>because I know the value of 1.e4 is 0.1 pawns for white >>>>and I know the value of 1.d4 is at most 0.08 pawns for white but fritz5 >>>>analyse the position after 1...d5 and waste time about it. >>>> >>>>fritz5 does not use the alpha beta for the tree it shows me and I do not >>>>understand why. >>> >>>When you are in k variation mode which is essentially what the correspondence >>>feature is, alpha beta only applies within each variation, not across >>>variations. >> >>I think it should be simple to use the alpha beta across variations. >>fritz5 uses the alpha beta for a very large tree I cannot see >>and it should be simple to use the alpha beta for the tree I see >>when the computer computes near 1 node per minute in this tree >>instead of 200000 nodes per second. >> >>Uri > > >Just how do you propose to do this? Alpha beta doesn't find an exact score >except for the best move. Forcing the program to find an exact score for every >candidate move slows the program down immensely. Using mini maxing across >variations is only possible if the variations are part of one big search and >then you are back to having an exact score for each candidate move which is too >slow in practice. > >-- >Komputer Korner I do not want the computer to find an exact score to every move in the tree in the example I gave I do not want the computer to find an exact score for 1.d4 based on the tree the computer calculates if I know: 1) the score of 1.e4 based on the tree the computer shows me (based on k variation mode) is 0.1 pawn for white 2)the score of 1.d4 Nf6 based on the tree the computer shows me is 0.08 in this case I do not want the computer to analyze the line after 1.d4 d5 but if 1.e4 1.d4 are the 2 best moves on the 2 variation mode the correspondence analysis calculates the exact value of 1.e4 and 1.d4 Uri
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