Author: Volker Böhm
Date: 21:53:31 09/21/04
Go up one level in this thread
On September 21, 2004 at 22:42:59, Stuart Cracraft wrote:
>Hi -- trying to avoid doing a null move based on draft from the
>hash table and R based on something some postings here from 1998.
>
>Have a look and see if this is accurate. I tried the same flag ==
>UBOUND code from the first block at (1) over at (2). Both separately showed
>worse results in testing than having neither.
Hi,
I do not understand your hashing code, comments following:
>
>#ifdef TT
> // Probe hash table. If seen before with equal or greater draft, return.
> // Otherwise, set alpha and beta bounds if available.
> // Last, if alpha exceeds or equals beta, return.
> if (retrieve(&length, &score, &flag, &hashmv)) {
>(1) if (flag == UBOUND && depth-R <= length && score < beta) donull = 0;
// What is "depth", why not using "sdepth"
// depth should be the REMAINING search depth
> if (length >= sdepth) {
// What is "length"? the stored remaining search depth?
// Name it hdepth then or something like this
// What is sdepth? the REMAINING search depth?
> if (flag == VALID) {
// The Exact score! Why naming it VALID but not EXACT?
> if (!(flags&NOTHING)) {
// What is "flags & NOTING" for?
// Hope it tests the presence of a hashmv
> savemove(&npv[ply][ply],hashmv);
> for (j=ply+1;j<pvl[ply+1];++j) {
> savemove(&npv[ply][j],npv[ply+1][j]);
> }
> pvl[ply]=pvl[ply+1];
> }
> return(score);
> }
> if (flag == LBOUND) alpha = MAX(alpha, score);
> if (flag == UBOUND) {
>(2) if (depth-R <= length && score < beta) donull = 0;
> beta = MIN(beta, score);
> }
> if (alpha >= beta) return(score);
// why not applying the "savemove-stuff" here ?
> if (legalmove2(bd,hashmv)) hashed = 1;
> }
> }
>#endif
The donull flag is set correctly. Hope the donull = 0 will result in not doing
donull. Do you make sure that donull != 0 otherwise?
I had the problem myself that with depth - R I´ve got some more nodes in the
search tree. Try depth instead of depth - R
Greetings Volker
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