Author: Mridul Muralidharan
Date: 13:26:05 03/23/04
Go up one level in this thread
On March 23, 2004 at 15:55:36, martin fierz wrote: >On March 23, 2004 at 14:56:04, Mridul Muralidharan wrote: > >>On March 23, 2004 at 11:31:18, martin fierz wrote: >> >>>On March 23, 2004 at 10:14:05, Tord Romstad wrote: >>> >>>>On March 23, 2004 at 09:11:14, martin fierz wrote: >>>> >>>>>On March 23, 2004 at 04:35:49, Tord Romstad wrote: >>>>>> >>>>>>How do other engines evaluate this position? >>>>> >>>>>IMO this question is not the right question to ask. i think gothmog is rather >>>>>good at giving up the exchange compared to other programs. >>>> >>>>That's a kind way to put it. :-) >>> >>>no, no. the exchange is valued too highly by most programs! >>> >>>>I would rather say that Gothmog values the exchange too little, and gives >>>>it up too often. It sacrifices the exchange more often than any other engine >>>>I have seen, and I am fairly sure it loses more games than it wins because >>>>of this. >>>> >>>>>it's static eval for >>>>>this position would be quite ok if the white bishop was on c1 for example, where >>>>>it's mobility is apparantly only very little bigger (one more square to go to). >>>>>therefore you have to ask not only what the static eval for the position is that >>>>>you gave, but also for the one with the bishop on c1. many engines will give >>>>>black a clear edge here because they are (too) materialistic. they will do this >>>>>in both positions. the really interesting question is whether any engine can >>>>>detect the HUGE difference between having the bishop on c1 or g1... >>>> >>>>One of the really embarassing things about Gothmog's eval of this position >>>>is that it doesn't even consider the bishop on g1 to be a bad biship. My >>>>bad bishop eval is based on the number of *blocked* pawns on squares of the >>>>bishop's colour. In the position we discuss, there are only two such pawns >>>>(on e3 and g3). Therefore Gothmog thinks that the g1 bishop isn't really >>>>that bad. It has limited mobility, but it should be easy to relocate it >>>>to a better square. >>> >>>perhaps you should change your definition a bit. the pawn on f2 is virtually >>>blocked too, and the pawn on c4 is rather blocked and with it the one on c3. in >>>any case, the f2-pawn should be recognizable as blocked. >>>to evaluate my bishops, i use a sum of c1*(blocked pawns on that color) + >>>c2*(unblocked pawns on that color). i think that is a better way of doing it. >>>still it's not good, because as said, the g1-bishop would be just fine on a3 or >>>on f4. >>> >>>>As so often, Gothmog's eval proves to be the worst of them all. >>>no!!! as i said you asked the wrong question! you didn't even answer the right >>>question yourself, and all others won't answer it either as i know them... the >>>right question is: >>> >>>*************************************************************** >>>"please give me your static eval with bishop on g1, c1 and a3". >>>*************************************************************** >>> >>>my answer is "-0.49 (g1), -0.51(c1), -0.35(a3)." >>> >>>as you can see, my answer is always about the same, and for example ridiculous >>>in that g1 is preferred over c1 (reason: the rook's mobility is smaller for >>>Bc1). >>> >>>i will bet another beer (you owe me one IIRC) that most of the people who >>>answered your post (and of who you think they are evaluating this better) have >>>similar problems. e.g. the position with the bishop on c1/a3 is roughly equal >>>(well, with the Ba3 you in fact immediately win a pawn, but just philosophically >>>speaking, white has little to fear with a pawn for the exchange and the bishop >>>pair) and all those guys who gave a big negative score for white will still be >>>giving a big negative score for white (because nobody is realizing that the >>>g1-bishop is the big problem, they just think exchange=2 pawns), and gothmog's >>>eval will be the superior one. >>> >>>let's see whether somebody answers my question above. if they do, you will be >>>very much happier about gothmog's eval again. >>> >>>cheers >>> martin >> >> >>Hmm , I think you lost a beer ;) > >not at all :-) >the bet would have been "most of those who answered tord's post". of these, only >richard has given the baron's eval for Bc1 / Bg1 - no real difference there. so >up to now it's 1 who doesn't understand to 0 who understand. you came later and >don't count :-) >anyway, tord didn't accept the bet i think... > Yes , as soon as I posted - I understood the logical flaw in my statement ! I completely overlooked the critical section "most of the people who answered your post" :) And nice of you to catch it too ;) A logically challenged Mridul >>My engine evaluates the positions as follows : >> >>Bishop on g1 -> -1318 >>Bishop on c1 -> -874 >>Bishop on a3 -> -500 > >nice! > >cheers > martin
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