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Subject: Re: How to detect combinations?

Author: Tony Werten

Date: 00:35:42 08/03/01

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On August 03, 2001 at 03:27:33, Tony Werten wrote:

>On August 03, 2001 at 01:08:22, Pham Minh Tri wrote:
>
>>Hi all,
>>
>>I saw that my weak engine quickly lost some games or missed some other victories
>>by not recognising many common combinations. I have written codes for detecting
>>them and tried many extensions. Unfortunately, they made the search tree grew
>>exponentially (2-6 times slower) but did not help much, many combinations were
>>still 4 or 5 plies deeper than the full search deep (8-9, some branches are
>>extended to 13-15). The situation was even worse when a combination did not make
>>any check or capture before mate.
>>
>>Could someone give me some suggestions/comments?
>
>Well, at least a useless one: You have to search deeper.
>
>Be carefull with extensions though. You have to limit them. The idea behind most
>extensions is to find something that otherwise would be hidden behind the
>horizon.
>
>A threat extension is a clear example of this (after heavy fail low on nullmove
>). If you do nothing you'll be checkmated, so extend. But do you really want to
>do that when there are still 8 plies of search left ? Those 8 ply should find
>the correct continuation, not your extension.
>
>Tony

BTW, you do have a quiescence search do you ?


>
>
>>Thanks in advance.
>>Pham



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