Author: Bas Hamstra
Date: 12:58:33 11/12/01
Go up one level in this thread
On November 12, 2001 at 15:22:39, Heiner Marxen wrote:
>On November 12, 2001 at 08:14:32, Gian-Carlo Pascutto wrote:
>
>>On November 12, 2001 at 06:59:51, Bas Hamstra wrote:
>>
>>>On November 12, 2001 at 04:46:19, Gian-Carlo Pascutto wrote:
>>>
>>>>On November 11, 2001 at 19:42:29, Bas Hamstra wrote:
>>>>
>>>>>Is there any documentation about linking Nalimov?
>>>>
>>>>probe.txt, which comes with the generator
>>>>
>>>>>I am not sure what score a probe() should return. I set up a FINE that is a mate
>>>>>in 23 (verified on nalimov's online TB site). However, when my probing function
>>>>>returns 32756. Some debugging in TBIndex.cpp learns that initially it found 113
>>>>>that is then converted to 32756 by macro S_to_L. Doesn't seem right. Shouldn't
>>>>>it just return the number of moves to mate eventually? Peeking in Crafty seems
>>>>>to indicate so.
>>>>
>>>>I figured out the conversion formula by setting up some positions
>>>>and looking at the values I got back until I figured it out.
>>>>
>>>>In Sjeng, it looks like this:
>>>>
>>>>if (tbScore == bev_broken) return KINGCAP;
>>>>
>>>> EGTBHits++;
>>>>
>>>> if (tbScore > 0)
>>>> {
>>>> return ((tbScore-bev_mi1)*2+INF-ply-1);
>>>> }
>>>> else if (tbScore < 0)
>>>> {
>>>> return ((tbScore+bev_mi1)*2-INF+ply);
>>>> }
>>>> return 0;
>>>
>>>Hi GianCarlo,
>>>
>>>I saw this in Crafty too. But that doesn't give me a realistic value at all.
>>>However if I use L_bev_mi1 (like in ExChess) in stead it comes more in the right
>>>direction. But that gives me a M13 in stead of the M23.
>>>
>>>(I checked in TBIndex.cpp the right squares are found)
>>>
>>
>>M23 = ((M13-1)*2)-1
>>
>>If you compare this to the formula above you will see it is similar.
>>
>>I'm sorry I cannot be of more help, but I think the best thing
>>to do is not to try to figure out how other formulas work (depends
>>too much on how you represent mate scores in your program), but
>>to set up a few positions where you know what the score should be,
>>and look at what the probing function gives you back.
>>
>>By comparing the two, it should not be hard to arrive at the correct
>>formula for your program. At least, thats how I did it :)
>>
>>--
>>GCP
>
>Here is the relevant part from Chest:
>
> v = L_TbtProbeTable(iTb, side, ind);
> XDB(1, printf("= eg_probe v=%d\n", (int)v); )
> /*
> * Now, we must translate back that value into a value,
> * which we understand...
> */
> if( v == L_bev_broken ) {
> scinc(egsc.prob_broken);
> q = EGQ_DUNNO;
> }else if( v == L_bev_draw ) {
> scinc(egsc.prob_draw);
> q = EGQ_DRAW;
> }else if( v > 0 ) { /* wins */
> /*
> * Deeper wins have smaller values.
> */
> scinc(egsc.prob_wins);
> q = EGQ_WINS_Q(1 + (L_bev_mi1 - v));
> }else { /* lost */
> /*
> * Deeper losses have larger values (less negative).
> */
> scinc(egsc.prob_loss);
> q = EGQ_LOST_Q(v - L_bev_li0);
> }
> XDB(1, printf("< eg_probe q=%d\n", (int)q); )
> return q;
>
>EGQ_WINS_Q(N) codes "mate in N"
>EGQ_LOST_Q(N) codes "is followed by mate in N"
>
>L_bev_mi1 == "mate in 1"
>L_bev_li0 == "lost in 0"
>
>That should be a usable starting point.
>
>Heiner
Thanks guys, figured it out. As always, it was something stupid.
Bas.
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