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As a result, the forced moves led to:
Strangely, Fritz evaluates this position at -5.37! This is better than the initial evaluation!
I thought I blundered and to my surprise, the following evaluation is actually better than the initial after the forced moves. It also doesn't seem to be a fluke as I have left it to analyze each position for about 30 minutes.
So going from being up a knight and a pawn (~+4 total pawn points) to losing a rook for a bishop (~+2 total pawn points), yields almost the same result? That's odd, I would have thought that the evaluation would have gone down at least a pawn and a half.
Someone please explain this to me....
In the first position 1. ... Nc5 is the second best move at a depth of 16 ply according to Fritz 8.
What you may be seeing is a horizon effect, in the first position Fritz can't see far enough to see just how bad white's position is. By the time it reaches the final position you posted it can see further and give a score based on a deeper look.
Originally posted by XanthosNZThat seems to make sense, but I left it for 30 minutes on each position using Fritz 9 on a single 2.4 Ghz AMD processor. I thought Fritz could calculate millions of positions in just a second, shouldn't it see far enough at with such specs?
In the first position 1. ... Nc5 is the second best move at a depth of 16 ply according to Fritz 8.
What you may be seeing is a horizon effect, in the first position Fritz can't see far enough to see just how bad white's position is. By the time it reaches the final position you posted it can see further and give a score based on a deeper look.
Originally posted by exigentskyNo. If you watch the depth to which Fritz has searched it gets to 9 ply even on a slow computer within seconds. Then each successive ply takes longer.
That seems to make sense, but I left it for 30 minutes on each position using Fritz 9 on a single 2.4 Ghz AMD processor. I thought Fritz could calculate millions of positions in just a second, shouldn't it see far enough at with such specs?
The number of positions that must be checked for a given ply depth increases exponentially (i.e. in the order of 2^n). From this it's easy to see that no matter how long you leave it you won't get far enough to see everything in a position (unless you manage to reach tablebase positions in your search).
Since I first checked the starting position you gave I haven't stopped Fritz from analysing, it's currently approaching 18 ply after 22 minutes on a very fast computer.
Originally posted by XanthosNZHiarcs 9 was at 13 ply almost instantly, but after four hours has extended it to 17 ply. It has examined just under 3 billion nodes.
To further illustrate my point after nearly 5 hours Fritz has reached a depth of 20 ply looking at the best two moves (this changes speed to a degree).
In doing so Fritz has looked at 12.5 billion nodes (individual positions).
current evaluation: -5.63
I have it examining only the best move.
Originally posted by exigentskyOnce again, I'm missing something.....exig, you said fritz scored the game at -5.3 or so...that is white's score. Fritz rates the white pieces, whether it's you or Fritz that is white.
Well, I only expected Fritz to give White a lower score when it lost two pawns , rather than a higher one.
So what's the problem?