Manual de Fritz 15 2015 | Page 53

General operation

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Moves: (Tree icon) Sometimes a move will appear in grey, which means that it
was never played, but leads to a position that results from some other line.
N: (N) The header displays the total number of games which led to the current
board position. The N column displays the number of games in which each move was
executed.
%: Percentage score achieved by the move, always from the point of view of the
colour to play. If the number of games is low, the percentage is given in grey because
it does not have great statistical significance.
Av: Elo average of the players of the move. If only a small percentage of the
players had a rating, then the number is given in grey.
Perf : Elo performance of the move. This is the rating a player would have
achieved in a fictitious tournament, playing the move in all his games.
Fact: The factor or "weights" allocated to each move control the probability with
which it will choose the move in a game. The value can range between –125 to +125.
The values are initially set to zero, but may change when the program actually plays
games in the individual variations. You could say that the program is learning from
experience. The weights can be manually modified by right-clicking a move and
selecting “Change weight”. To reset all weights click Edit – Openings book – Reset
weights. After that, the program will use only the purely statistical information to
select its moves.
Prob and [%]: The first value is the purely statistical probability of the move,
based on the number of times it was played and the results achieved in the games
that went into the book. This is the probability of the move being played by the
program as long as the weights have not been changed – either manually or by
automatic learning. The value on the right [%] is the practical probability of the
program playing the move. This is a product of the statistical evaluation and the
weights. If you change the latter you can see how the [%] value (but not the “Prob”)
changes. In Book options you can determine how much the weights influence the
probability of play.

At the bottom of the Openings Book window there is a graphic display of the
percentage wins, losses and draws that were achieved with the highlighted move.
How to navigate the tree
Use the up/down cursor keys to move the headlight bar up and down.
Use the right/left keys to move forward and backwards in the variations.
Click a move with the mouse to move forwards in a variation.

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