Author: James Swafford
Date: 09:50:57 05/29/04
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On May 29, 2004 at 12:50:12, Bas Hamstra wrote: > > >On May 29, 2004 at 11:10:47, James Swafford wrote: > >>In a recent post, Tord suggested setting a flag in >>the search when the hash table suggests a fail high, and >>testing whether the search would indeed fail high. >> >>The idea seems so simple I'm embarassed I haven't thought >>of it before. :) >> >>I've been 'pretty sure' for a long time that I've got some >>nasty hash bugs. I'm in the mood to exterminate them. >> >>Last night I implemented Tord's idea and, to my dismay >>(but not to my surprise) my hash table is saying 'fail >>high' when the search wouldn't have failed high. And- >>it doesn't take very long. :) >> >>This seems like a nasty thing to debug. I'm comtemplating >>how I might go about it. I'm hoping some of you can >>provide some suggestions... >> >>-- >>James > >What you describe is not a good way of finding HT bugs, IMO. To start with, hash >can cause inconsistent search results, even with completely bugfree code. Want >to track hash bugs? Do this: write code to completely recalculate hashkey from >scratch. Compare this key with the incremental key at every node. Analyze and >fix differences until they are all gone. I already do this... my keys are fine. > > >Bas.
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