Author: Severi Salminen
Date: 13:43:10 11/22/00
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>Be careful. It is possible to back up a value of "alpha" after searching every >move and finding that the successive ply fails high each time. You now have >a score you are backing up, but you have _no_ PV to go along with it. If your >test is wrong, you can break. Same thing happens on a fail high. You can back >up the current move as a best move for the 'fail-high PV', but you will have >_no_ moves below that node in the PV array. It will probably contain old >moves that were not overwritten. This will wreck you. Yes, this seems to be the problem. I found a position (mate in one for black) and after performing a 2 ply search my program thinks that the PV has two moves (which is obviously false). So when it tries all replies for white it sees that there are no legal replies and fails low, but doesn't know how to inform that the PV is not right. Now, how could I get rid of this annoying problem, so what are all the "exceptions"? I just can't figure it out... Severi
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