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Subject: Re: a number and two questions for bob

Author: Vincent Diepeveen

Date: 04:23:40 05/05/04

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On May 05, 2004 at 05:10:36, martin fierz wrote:

>hi bob,
>
>rereading your DTS paper (you sent me a copy once), you reported 24 speedup
>numbers for 4 processors (given in the end, for anybody interested).
>
>i get (using a black box):
>
>av. speedup: 3.65
>standard deviation of sample: 0.31
>standard error of average 0.064
>
>so: average speedup(N=4) = 3.65 +- 0.07 would be a nice way to put this.

i have all dts numbers in an excel sheet with search times and node counts.

that's easier to do statistics with.

>for those who don't have the paper, this was done on a cray, so it's not
>comparable to crafty on an average N-way box you might have (and methinks this
>experiment was done with cray blitz).
>
>this leads to two follow-up questions:
>1) where does the 3.1 for crafty come from you usually quote? did you ever
>publish a similar set of numbers for crafty? any .pdf / .ps to download for
>that? where do the numbers 2.8 / 3.0 of vincent+GCP come from? how many
>positions were in that test?

30 positions tested by GCP. I still have the outputs if you want them

>2) can you give a similar error estimate for the 3.1 number (both std. dev and
>std. error)? or even better, a full set of numbers so that i can do with them
>whatever i want, since you seem so reluctant to compute std/ste? :-)
>3) right, question 3 of 2 :-): you claimed somewhere deep down in the other
>thread that it matters whether you look at related or unrelated positions. you
>could prove/disprove this experimentally with a set of related positions (eg
>from games of crafty on ICC) vs. a large test set (e.g. WAC).
>
>why is this important? without error estimates, you can discuss forever whether
>2.8/3.0 are the same as 3.1. without hard data on 3) you can also discuss
>forever whether the issue in 3) matters or not, and if it does, in what way and
>how important it is.
>
>this is a simple experiment to do, and since my profession is about measuring
>numbers i don't understand that you don't do it ;-)
>
>cheers
>  martin
>
>
>results in table 4 for 4 processors:
>3.4
>3.6
>3.7
>3.9
>3.6
>3.7
>3.6
>3.7
>3.6
>3.8
>3.7
>3.8
>3.8
>3.5
>3.7
>3.9
>2.6
>2.9
>3.8
>3.9
>4.0
>3.7
>3.8
>3.9



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