Author: Jeremiah Penery
Date: 22:01:36 09/27/00
Go up one level in this thread
On September 27, 2000 at 04:45:38, Eduard Nemeth wrote:
>[D]8/8/p3R3/1p5p/1P5p/6rp/5K1p/7k w - - 0 1
>
>Shredder 4 and Fritz 6a this don't find !
I have a modified Crafty that solves this well enough:
7-> 0.33 -0.04 1. Re1+ Rg1 2. Rf1 Rxf1+ 3. Kxf1 a5
4. bxa5 b4 5. a6 b3
8 0.34 -- 1. Re1+
8 1.85 ++ 1. Re1+!!
8 1.86 0.61 1. Re1+ Rg1 2. Rf1 Rxf1+ 3. Kxf1 a5
4. bxa5 b4 5. a6 b3 6. a7 b2 7. a8=Q#
8-> 1.88 0.61 1. Re1+ Rg1 2. Rf1 Rxf1+ 3. Kxf1 a5
4. bxa5 b4 5. a6 b3 6. a7 b2 7. a8=Q#
9 1.89 -- 1. Re1+
9 5.86 ++ 1. Re1+!!
9 5.87 Mat07 1. Re1+ Rg1 2. Rf1 Rxf1+ 3. Kxf1 a5
4. bxa5 b4 5. a6 b3 6. a7 b2 7. a8=Q#
9-> 5.89 Mat07 1. Re1+ Rg1 2. Rf1 Rxf1+ 3. Kxf1 a5
4. bxa5 b4 5. a6 b3 6. a7 b2 7. a8=Q#
Part of the modifications I did was to not do a nullmove at all when the total
depth is 5 or less, and it also doesn't use nullmove when depth_remaining is 2
or less. The normal "adaptive null-move reduction" has also been changed, to
only use r=3 when depth is more than 12 instead of the normal 6. Here's the
modified parts of the nullmove code from Crafty's search.c
if (iteration_depth > 5 && depth > 2) {
# if defined(NULL_MOVE_DEPTH)
....
null_depth=(depth > 12*INCPLY) ? 2*INCPLY : 3*INCPLY;
....
# endif
}
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