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Subject: Re: No explosions

Author: Sune Fischer

Date: 04:11:31 01/13/02

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On January 13, 2002 at 06:55:14, Uri Blass wrote:

>On January 13, 2002 at 06:48:22, Sune Fischer wrote:
>
>>On January 13, 2002 at 05:14:44, Uri Blass wrote:
>>
>>>>>If you find the legal moves incrementally, how can you check for
>>>>>numberofmoves==1 at the first move, or do you simply forget about it then?
>>>>>
>>>>
>>>>In the case of check, I create only check evasions, that is, _real_ legal moves.
>>>>Partly because it is faster for move generation, and partly because it makes the
>>>>check for this extension a lot faster.
>>>>
>>>>>And why the inCheck and numberOfMoves==1, can't you forget about the inCheck and
>>>>>just extend +1 if there is only one legal move?
>>>>
>>>>No because I only do it of there's a check also. I don't generate real legal
>>>>moves at all nodes, only check nodes.
>>>
>>>If I understand correctly numberofMoves means number of legal moves when you are
>>>in check
>>
>>Yes
>>
>>>and number of pseudo legal moves when you are not in check.
>>
>>I'm not sure how he does that, I think he finds the moves incrementally which is
>>faster than generating all the moves. It would be a problem then to know how
>>many possible moves there are, which is why he needs the inCheck condition.
>>
>>I do it differently, I almost never generate only legal moves. I simply do not
>>know when the king is in check (I don't use bitboards for movegen), so I have to
>>go one ply deeper to see if the king is captured. This will lead to trouble at
>>some point, so I'm thinking of changing it.
>>
>>>In this case you still can extend +1 only if NumberofMoves=1 because the only
>>>case when Numberofmoves=1 the number of legal moves is always at most 1(it can
>>>be also 0 in some stalemate situations when there is only 1 pseudo legal move)
>>
>>There will be more than 1 pseudo legal move if there are more than one attacked
>>square around the king.
>
>I understand it but my point is that numberofmoves=1 when the king is not in
>check means exactly one pseudolegal move and it means at most 1 legal move.

But how will he now that numberofmoves=1 if he finds them incrementally?
If king not inCheck -> first try the hashmove, then......
When he is about to try the hashmove, he has no idea about the number of pseudo
moves.


>Uri



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