Author: George Tsavdaris
Date: 14:14:23 02/05/04
Go up one level in this thread
On February 05, 2004 at 16:57:30, Matthew Broderbund wrote:
>Hello,
>
>What do these parameters of the Fritz8 engine mean?
>
>Contempt value
>Selectivity
>Futility prunning
>Pawn levers
>Scale evaluation
>
>What do these parameters of the Shredder7 engine mean?
>Forward prunning
>Threads
From the chessbase help:
Contempt value: This tells the program whether to accept or avoid a draw. If the
value is positive, then it will avoid lines that lead to a forced draw. If it is
negative, then the program will try to force such lines itself. The value is
given in "centi-pawns" (100ths of a pawn). +100 means Fritz would be willing to
sacrifice a pawn for the draw, –100 that it will accept a draw even if it is a
pawn up.
Selectivity: Fritz uses a search technique that is highly "selective". This
means that instead of looking at every single line of play, however stupid, it
tries to narrow things down to meaningful variations. This allows it to go much
deeper, but it can occasionally miss a highly unusual continuation. This is the
case in positions involving "zugzwang" (i.e., positions in which one side faces
disaster because he is forced to make a move). This can be corrected by reducing
the selectivity value – when solving studies you may want to set it to zero,
since here zugzwang is very often involved. However, remember to set it back to
a higher value for normal games. Otherwise, the search depth will be decreased,
and the program will not be as strong.
Futility pruning: This is an aggressive method of narrowing down the search.
It allows the program to go much deeper, but it also increases the possibility
that it will oversee something.
Scale evaluations: This determines how much weight the program will give to
material as opposed to positional considerations. The value is given in percent,
a positive number increases the weight of positional criteria, negative values,
that of material.
Pawn levers: The program prefers positions with pawn levers.
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Forward Pruning :This activates an additional selection within the search
tree, allowing the program to find deeper combinations. The general search speed
is increased noticeable. The value given determines the depth (in ply) at which
Shredder will stop checking all lines and only continue with those it considers
meaningful.
Threads: Shredder can run on multi-processor systems. Here you tell it how
many of the available processors it should use. The engine can handle a maximum
of eight processors.
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