On Wed, Jul 04, 2007 at 11:08:21AM +0200, hubert depesz lubaczewski wrote: > On 7/4/07, Joshua N Pritikin <[EMAIL PROTECTED]> wrote: > >From where are you quoting? I was quoting from: > > > >http://www.sai.msu.su/~megera/postgres/gist/tsearch/V2/docs/tsearch2-ref.html > > i was quoting file > http://www.sai.msu.su/~megera/postgres/gist/tsearch/V2/docs/tsearch-V2-intro.html
So that one is fine. Only the reference could use some clarification. > >actually oleg supposed not to use best rank, but just use the formula as > >> given - rank/(rank+1) to get rank in range of 0 to 1. > >OK, then what does the +1 mean in your formulae? Consider these results > >from [1]. rank/(rank+1): 0.19/.1 = 1.9, .1/.1 = 1, etc. That doesn't > >make sense. The reciprocal also doesn't make sense. So what does Oleg > >mean? I was guessing that Oleg meant to divide the rank column by the > >first rank, that is, by 0.19 so you would get 1, .52, .52, etc. > > +1 means: add one to. > for example: for rank = 0.1 you get: 0.1/(0.1+1) = 0.1/1.1 = 0.0909 > for rank = 0.5 you get: 0.5/(0.5+1) = 0.5/1.5 = 0.3333 D'oh! I see. > i think that notation: rank+1 is pretty readable. > > additionally - sorry but i dont understand your calculations. what is > 0.19/.1 > ? how did you get the .1? I was imagining that "rank+1" was the second row of the rank column. Sorry for the confusion. -- Make April 15 just another day, visit http://fairtax.org ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
