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Subject: Re: Proving something is better

Author: Bruce Moreland

Date: 15:23:28 12/18/02

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On December 18, 2002 at 16:15:52, Sune Fischer wrote:

>By beef was with those claiming time to solution is all that makes sense.
>Your original example was to add a bunch of eval and then not count it as nodes,
>my point was that you then change more than just the search. You alter the whole
>test bench, there is no base for comparison at all when it's basicly a different
>program.

My example was extreme, and I was hoping to reduce the whole thing to a black
box.

If all you get to see is what comes out of the box, you draw conclusions about
what is better or worse based upon what comes out of the box.

If you have religion about what you *think* is in the box, the conclusions you
draw are different.

These algorithms are all processes that take input, consume processor time, and
produce an output.  You cannot compare their efficiency without factoring in
differences in processor time.

If one of them consumes more time, you *expect* it to produce a better result,
even if it is marginally inferior.  You certainly don't assume it's *superior*.

I was trying to point out that it was easy to redefine a node in order to cause
one program to take markedly more time.

I see this as being approximately as honest as changing the search algorithm so
the program consumes more time.

>>R=3 finds 65 solutions in one unit of time.  R=2 finds 66 solutions in 2.2 units
>>of time.  Does this support the conventional logic that R=2 is better than R=3?
>>That would be a very poor leap of faith.
>
>No that is not conventional logic. As I said, two parameters going off in
>opposite directions and you are lost. You need both to point in the same
>direction to make a safe conclusion.

I agree with this fully.

>This is why I suggested using a single parameter (nodes to solution), so that
>you could always conclude something from the experiment. But even that has
>certain problems.

Nodes to solution is fine as long as each node takes the same amount of time,
otherwise this differs from time to solution, which is what you really want.

>However Omid argues that VR is improving stability by design, and it is faster
>than R=2. Score 2-0 for VR=3 over R=2.
>
>Whether the nodes to ply and R=3 comparisons are valid I don't know, I would
>have to re-read the article. I use R=2/3 so I definitely would need to do the
>experiment anyhow.

I argue that:

1) Omid's argument that VR=3 is better than R=2 is consistent.
2) It is important to show this is not because in the reality of Omid's program,
R=3 is better than R=2.

bruce



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