Author: Martin Giepmans
Date: 05:29:32 12/30/01
Go up one level in this thread
On December 29, 2001 at 21:57:44, Tom Kerrigan wrote: >On December 29, 2001 at 20:42:18, Martin Giepmans wrote: > >>On December 29, 2001 at 17:14:45, Tom Kerrigan wrote: >> >>>On December 29, 2001 at 09:37:55, Martin Giepmans wrote: >>> >>>>On December 29, 2001 at 05:11:26, Tom Kerrigan wrote: >>>> >>>>>Here's my idea. >>>>> >>>>>You have a position and you want your program to play a certain move (which it >>>>>presumably isn't playing). You run this algorithm: >>>>> >>>>>1. Search the position, get a PV. The evaluation of the last position of the PV >>>>>is eval(1). >>>>>2. Search only the move that you want your program to make, get a PV. This >>>>>end-point evaluation is eval(2). >>>>>3. Figure out which eval terms are different between eval(1) and eval(2). >>>>>Decrease the weights of all the different eval(1) terms slightly. Increase the >>>>>eval(2) terms slightly. >>>>>4. Repeat until the program plays the move you want. >>>>> >>>>>You could run this on lots of positions from GM games, to get your program to >>>>>play like a GM. (At least in some positions, heh.) >>>>> >>>>>Has this been done before? Are there any glaring problems with this idea? Does >>>>>anybody want to try this? If so, I'd like some credit for it. If not, I'll >>>>>probably get around to trying it sometime... >>>>> >>>>>-Tom >>>> >>>> >>>>I think one of the bigger problems with this idea is that the minimax-eval >>>>at the root does not only depend on the eval of the last position of the PV. >>>>It usually also depends on the eval of many other positions in the search-tree. >>> >>>Hence iterating the searches. >>> >>>-Tom >> >> >>Hi Tom, >> >>I'm afraid iterating doesn't solve this, because many positions >>that influence the search (and ultimately the move that is chosen >>at the root) will never appear at the end of a PV. >>So I guess that looking at endpoints is simply not enough. > >I'm not sure what you mean. The only "influence" that other positions have on >the root node is that they're not good enough to end up at the end of the PV... > >-Tom Well, how do you discover that a position is good enough or not good enough? "good enough" is relative. So somehow you will have to compare the position with other positions, right? Where are those other positions? It's not so easy to explain, but I think you will understand what I mean if you construct an example of a searchtree and see for yourself what happens. Martin
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