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Subject: Re: For the Record .. Deeper search & Eval Mate in 14

Author: Roger Brown

Date: 03:31:51 12/04/05

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>How often have you seen a PV show Mate in 150? Deep Search maybe 18/45 Ply.
>It doesn't show a forcing line of course.


Obviously such a display was nonsense then - unless it was Chest UCI...  The
program sees a decisive advantage for itself but is unable to properly resolve
it.


>With time the PV evtually finds Mate in lesser moves,and then with a Fail High
>it changes rapidly, and maybe at Ply 35/65 can demonstrate the Mate.
>Because the Program sees a Mate after a 1/2 move is made from the Mate in 14,
>means that the line being evaluated changed slightly allowing a Mate in 11.


I am not following you here *but* clearly, going from mate in 14 to 11 is
allowable...


>The next 1/2 move = 1 Ply the best line again shows Mate in 14.

No!  Chandler, if there is a mate in one according to the computer then it must
have already considered the defences that were possible.  To go to mate in ten
on the same position indicates an error in the mate in one evaluation.


>No one expects the Program to show the forcing line at the time it finds the
>Mate in 14.



Then how did it arrive at the mate in one then go up to mate in ten?  Isn't a
mate in one forcing?  Or a mate in five?  I admit that my "mate in five" may
easily be a mate in ten but that would support my argument that any program that
behaved similarly would have a bug somewhere.



>The Engine would have to search to 28 Ply to do that.
>Programs evaluate 1 Ply at a time.
>Hash Tables are not perfect, if so, Computers would 'never' make blunders,
>yet in games, we see it all the time. They just plain make 'bad' moves
>at critical times. Why is that? Because they make the best move found..
>at the time the software tells it to move.


Why are you discussing hash tables and perfect play?  How is a hash table made
imperfect or perfect?


>How often have you seen a Program announce Mate in 12 for example, but when you
>force the play it turns out to be 15 or more?
>Top Programs are not the best Mate Finders!


We agree here...


>Simple as that..
>OK?


No.  I suspect though that we have to agree to disagree.  I am not sure that I
possess the rquisite gifts to proceed any further.


Later.



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