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 or actually - it's copy provided with sources of postgresql in contrib/tsearch2/docs directory.
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 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? depesz