After a soul-destroying experience this afternoon, I have released my latest build of Francesca, named 0.16. You can download it from my website, http://www.silentshark.co.uk

The soul-destroying experience was in Olivier's brilliant Openwar 8 tournament (see http://www.open-aurec.com/chesswar ...

mcostalba wrote: Anyhow I found that search parameters (LMR, futility, null search reductions, etc) are very insensible to variations: you need to kick them hard to see a change (good or bad).

Yeah, it's interesting how seemingly significant tweaks (or bugs) in this area have so little effect on strength..

when null move was established, this asymmetric search was outsearched by symmetric null move programs

Perhaps could be interesting to note that null move is not symmetric, is applied only to the nodes above beta (although there are variations here, some engine uses a margin subtracted from beta ...

in those days you could test the asymmetry in richard langs programs with test positions.
e.g. karpov-topalov
rqr3k1/3Qbp2/p1n1p1p1/1pp5/2P2P2/2N3P1/PP3PB1/R3R1K1 w - - 0 1



It would be interesting to understand if any of these "old" asymmetric algorithms would work in the frameworks in use ...

Ovyron wrote:I don't think it will measure correctly with engines so far apart in strength.

Maybe.. Perhaps I'll try another test.

I bet it comes out reasonably similar though.

So the big question is why LMR only gives 65 Elo for SF, but is worth closer to 200 elo to crafty..

Any theories on this?

- better lmr implementation in crafty?
- other fwd pruning in SF means lmr benefit is reduced?
- some unexpected, emergent behaviour, e.g. unexpectedly good interaction ...

So the big question is why LMR only gives 65 Elo for SF, but is worth closer to 200 elo to crafty..

Any theories on this?

- better lmr implementation in crafty?
- other fwd pruning in SF means lmr benefit is reduced?
- some unexpected, emergent behaviour, e.g. unexpectedly good interaction ...

So the big question is why LMR only gives 65 Elo for SF, but is worth closer to 200 elo to crafty..

Any theories on this?

- better lmr implementation in crafty?
- other fwd pruning in SF means lmr benefit is reduced?
- some unexpected, emergent behaviour, e.g. unexpectedly good interaction between ...