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Subject: question about smarthink extension

Author: Daniel Shawul

Date: 02:28:28 06/09/04


Hi

I read about the  botvinnik-markoff extension in ccc archieve
I have two questions concerning the method

here is how i understood it

  do_null
  search(-beta+1,-beta,d-R-1)
  undo_null
  if(score > beta)
    return score
  else
  {
    if(score==-MATESCORE+ply+1)
        matethreat extension
    else if ( score < MARGIN)
    {
       threatmove = bestmove of ply+1
       if(to(threatmove) == to(threatmove of ply-2)
          bm extension
    }
  }

  qn1. What is the value of margin. -2,-5 pawns?
       Or should it be something like score < alpha - 2pawns
       or   score < material balance - 2pawns

  qn2. Should i trigger the extension also when the piece being threatened
       at ply-2 moves and the to square is now threatened?

best
daniel




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