Author: Jeroen van Dorp
Date: 19:40:17 03/01/04
Go up one level in this thread
On March 01, 2004 at 16:31:27, Darren Rushton wrote:
>It's probably in the manual, but I've always wondered what the significance of
>the colour coding of the text is in the thinking lines.
>
>What do red text, green text and black text actually mean. (I guess red means
>someones made a mistake!)
>
>Also, what does that little "light" in the analysis window signify (it can be
>grey, red, yellow or green)??
<quote>
Engine window
--------------------------------------------------------------------------------
This program provides you a wealth of information on the engine thought
processes during the course of a game. This is the “search information” and
reflects what the computer has found while calculating its next move.
On the top left you can see which chess engine is currently calculating the
moves (the actual name will be displayed).
The move it is calculating is 22...Rxf6, and this is the first of 49 legal
moves.
The “Stop/Go” button allows you to stop and then restart the calculation, or
force a move.
With the “+” and “–” buttons you can increase or decrease the number of
lines that are calculated in parallel (these buttons disappear during a regular
game and are only available in analysis mode).
In the second line there is a lamp which turns red when the engine finds
something dramatic (i.e. when the value suddenly rises or falls dramatically).
An arrow pointing up or down denotes a “fail high” or “fail low”, which simply
means that the computer has discovered something good or bad in the position but
doesn't yet know what it is.
The number to the right of the lamp gives the position value, above 2.91.
The evaluation is expressed in pawn units, always from the point of view of
White. In the example the program considers the white position to be better by
the equivalent of 2.91 pawns. This means that White is a piece down – either a
bishop or a knight, which are both equivalent to about three pawns. Rooks are
worth five and the queen about nine pawns. If the values deviate from whole
numbers this is the result of additional positional considerations (mobility,
deployment of pieces, king safety, pawn structure, etc.). In addition to the
precise pawn values, the evaluation is also given in standard chess symbols: +–
means White is winning, –+ means Black is winning, = means the position is
drawish.
The search depth tells you how many moves deep the search has progressed.
The value is in “ply” or half-moves. The first number gives you the “brute
force” depth, the second is the depth to which certain critical lines have been
investigated. The value is in “ply” or half-moves. For instance a display of
“depth = 12/29” means that the program has looked at every continuation to a
depth of 12 ply (six moves), while some promising or dangerous continuations are
being examined up to a depth of 29 ply.
After it has played a move, Fritz shows you which move it expects you to
choose (in the field after the depth field).
Finally you can see the speed at which it is running: “292kN/s” means the
engine is generating and evaluating 292,000 positions per second (“kilo nodes
per second”). Right-click this display if you want to see the total number of
positions instead.
In the section below the search information you see the “principle
variation”, i.e. the best continuation the program has found so far. Together
with the search information the total number of positions is also given. In the
above example the engine has looked at 371 million positions to come up with the
third line. You can right-click the display and select more or less information,
and decide whether the history of the search should be scrolled. You can also
insert a small “variation board” on which you can play through the main line the
program is considering.
</quote>
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