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how to measure frequency of hash collisions.
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Don Dailey



Joined: 29 Apr 2008
Posts: 4323
PostPost subject: Re: how to measure frequency of hash collisions.    Posted: Sun Jun 17, 2012 12:23 am Reply to topic Reply with quote
Daniel Shawul wrote:
Quote:

No, you miss the point. With zobrist hashing using xor you really have 64 1 bit keys, not 1 64 bit key. The random number tables are not 64 bit random numbers, they each are arrays of 64 random bits. There is no interaction across bits. So the 60 bit key and the 4 bit key can be thought of as totally separate.

I didn't miss a point. Like I said the 4 bit keys have to be generated from a different hash function. Now after I explained it to you ,you start start changing your words. You were saying taking the lower 60 bits of the 64 key will suffice...
Quote:

So if you have an issue with this, then generate the 60 bits, then generated the 4 bits separately and combine them in a single 64 bit random number for each entry. It's exactly what you think will "fix" the problem. Semantically there is no difference between combining them or storing them in a separate table.

It is not an "me having an issue", it is a _must_ that you generate them using different hash functions. Storing them in a separate table is the same thing so why you want to make that an issue is beyound me. I suggest you read your first post again and check if you have said anything about generating them with different hash function. Look at Ed's post point number (3) to see how you should sayed it. it is clear I agree with him.
Quote:

Honestly, when I saw the problem posed I was suggesting a good way to accurately estimate the hash collision rate, none of the suggestions posted on this thread can judge the quality of the Zobrist hashing because they all require separate verification bits and the method falls apart no matter what unless those verification bit's are properly generated. If you can do that then you might as well generate all the random bits that way.

Man the way you change your words borders to being a lair... Read your first post again. You made no mention of separately the 60 bit and 4 bit key to be generated separately !!


Can someone please arbitrate this for us? Not a moderator but just someone who understand what I am saying, what he is saying and can figure out who is misunderstanding what? If I am wrong I will admit it. If I lied I didn't know it but if I can see it I will apologize.
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Subject Author Date/Time
how to measure frequency of hash collisions. Daniel Shawul Sat Jun 16, 2012 4:45 pm
      Re: how to measure frequency of hash collisions. Marcel van Kervinck Sat Jun 16, 2012 5:25 pm
            Some tests: Attn Don Daniel Shawul Sat Jun 16, 2012 6:25 pm
                  Re: Some tests: Attn Don Daniel Shawul Sat Jun 16, 2012 7:15 pm
      Re: how to measure frequency of hash collisions. Don Dailey Sat Jun 16, 2012 9:17 pm
            Re: how to measure frequency of hash collisions. Daniel Shawul Sat Jun 16, 2012 10:05 pm
                  Re: how to measure frequency of hash collisions. Don Dailey Sat Jun 16, 2012 10:23 pm
                        Re: how to measure frequency of hash collisions. Don Dailey Sat Jun 16, 2012 10:29 pm
                        Re: how to measure frequency of hash collisions. Daniel Shawul Sat Jun 16, 2012 11:06 pm
                              Re: how to measure frequency of hash collisions. Don Dailey Sat Jun 16, 2012 11:39 pm
                                    Re: how to measure frequency of hash collisions. Kevin Hearn Sat Jun 16, 2012 11:50 pm
                                          Re: how to measure frequency of hash collisions. Don Dailey Sun Jun 17, 2012 12:08 am
                                          Re: how to measure frequency of hash collisions. Daniel Shawul Sun Jun 17, 2012 12:40 am
                                    Re: how to measure frequency of hash collisions. Daniel Shawul Sat Jun 16, 2012 11:54 pm
                                          Re: how to measure frequency of hash collisions. Don Dailey Sun Jun 17, 2012 12:23 am
                                    Re: how to measure frequency of hash collisions. Marcel van Kervinck Sun Jun 17, 2012 7:55 am
                  Re: how to measure frequency of hash collisions. Don Dailey Sun Jun 17, 2012 1:26 am
      Re: how to measure frequency of hash collisions. Ed Schroder Sat Jun 16, 2012 9:36 pm
            Re: how to measure frequency of hash collisions. Daniel Shawul Sat Jun 16, 2012 10:01 pm
      Re: how to measure frequency of hash collisions. H.G.Muller Sat Jun 16, 2012 10:12 pm
            Re: how to measure frequency of hash collisions. Daniel Shawul Sat Jun 16, 2012 10:31 pm
            Re: how to measure frequency of hash collisions. Daniel Shawul Sun Jun 17, 2012 2:00 am
                  Re: how to measure frequency of hash collisions. Rémi Coulom Sun Jun 17, 2012 8:30 am
                        Re: how to measure frequency of hash collisions. Daniel Shawul Sun Jun 17, 2012 10:49 am
                        Re: how to measure frequency of hash collisions. Daniel Shawul Sun Jun 17, 2012 2:58 pm
                              Re: how to measure frequency of hash collisions. Ronald de Man Sun Jun 17, 2012 3:41 pm
                                    Re: how to measure frequency of hash collisions. Daniel Shawul Sun Jun 17, 2012 5:58 pm
                                          Re: how to measure frequency of hash collisions. Ronald de Man Sun Jun 17, 2012 9:06 pm
                                                Re: how to measure frequency of hash collisions. Daniel Shawul Sun Jun 17, 2012 9:57 pm
      Re: how to measure frequency of hash collisions. Lucas Braesch Sun Jun 17, 2012 3:02 am
            Re: how to measure frequency of hash collisions. Ronald de Man Sun Jun 17, 2012 3:08 pm
            Re: how to measure frequency of hash collisions. Daniel Shawul Sun Jun 17, 2012 6:12 pm
                  Re: how to measure frequency of hash collisions. Ronald de Man Sun Jun 17, 2012 9:14 pm
                        Re: how to measure frequency of hash collisions. Daniel Shawul Sun Jun 17, 2012 10:01 pm
      Re: how to measure frequency of hash collisions. Joshua Shriver Wed Jun 20, 2012 8:45 pm
            Re: how to measure frequency of hash collisions. Ronald de Man Wed Jun 20, 2012 10:44 pm
                  Re: how to measure frequency of hash collisions. Joshua Shriver Thu Jun 21, 2012 1:51 am
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