Re: ts_rank

I'm sorry, my plane to Nepal is waiting me :) I'll be back in the
midst of November. In short, ts_rank is based only on frequencies of lexems
and doesn't count distance between query lexems. Also, it supports only
primitive queries.

Oleg
On Wed, 12 Oct 2011, Bruce Momjian wrote:

> Bruce Momjian wrote:
>> Mark wrote:
>>>> There's some potentially useful information here:
>>>> http://www.postgresql.org/docs/9.0/interactive/textsearch-controls.html#TEXTSEARCH-RANKING
>>>
>>> Thanks for reply. I was reading the documentation of PostgreSQL, but there
>>> it is not written the name of the used methods. Everywhere there is written,
>>> that ts_rank use standard ranking function. But it is difficult to say which
>>> is the standard function.
>>> Somewhere I found that it is maybe based on Vector space model and it seems
>>> to be truth, because in the code of tsrank.c is counted the frequency of
>>> words, but I am not sure of that :-(
>>
>> Oleg, Teodor, can you give me a description of how ts_rank decided how
>> to rank items? Thanks.
>
> Any news on this question?
>
>

Regards,
Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg(at)sai(dot)msu(dot)su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83