Possible error in FTS5 docs

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Possible error in FTS5 docs

Philip Bennefall
Hi all,

While reading through the draft documentation for FTS5, I noticed the
following in section 4.1.1:

"The built-in auxiliary function bm25() returns a real value indicating
how well the current row matches the full-text query. The better the
match, the
larger the value returned."

Then, a little further down it says:

"In order to avoid this pitfall, the FTS5 implementation of BM25
multiplies the result by -1 before returning it, ensuring that better
matches are assigned
numerically lower scores."

Is this a mistake, or did I misunderstand something?

Also, I am curious to know whether the developers are able to estimate
roughly when the FTS5 extension might appear in an official release of
SqLite?

Kind regards,

Philip Bennefall
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Re: Possible error in FTS5 docs

Dan Kennedy-4
On 06/19/2015 08:34 PM, Philip Bennefall wrote:

> Hi all,
>
> While reading through the draft documentation for FTS5, I noticed the
> following in section 4.1.1:
>
> "The built-in auxiliary function bm25() returns a real value
> indicating how well the current row matches the full-text query. The
> better the match, the
> larger the value returned."
>
> Then, a little further down it says:
>
> "In order to avoid this pitfall, the FTS5 implementation of BM25
> multiplies the result by -1 before returning it, ensuring that better
> matches are assigned
> numerically lower scores."
>
> Is this a mistake, or did I misunderstand something?

It's a mistake. Should be "The better the match, the numerically lower
the value returned" or similar.

Thanks for pointing this out.

Dan.

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Re: Possible error in FTS5 docs

Philip Bennefall
Thanks, Dan. Do you have any idea when FTS5 will be merged into the
amalgamation, if at all?

Kind regards,

Philip Bennefall

On 6/19/2015 8:54 PM, Dan Kennedy wrote:

> On 06/19/2015 08:34 PM, Philip Bennefall wrote:
>> Hi all,
>>
>> While reading through the draft documentation for FTS5, I noticed the
>> following in section 4.1.1:
>>
>> "The built-in auxiliary function bm25() returns a real value
>> indicating how well the current row matches the full-text query. The
>> better the match, the
>> larger the value returned."
>>
>> Then, a little further down it says:
>>
>> "In order to avoid this pitfall, the FTS5 implementation of BM25
>> multiplies the result by -1 before returning it, ensuring that better
>> matches are assigned
>> numerically lower scores."
>>
>> Is this a mistake, or did I misunderstand something?
>
> It's a mistake. Should be "The better the match, the numerically lower
> the value returned" or similar.
>
> Thanks for pointing this out.
>
> Dan.
>
> _______________________________________________
> sqlite-users mailing list
> [hidden email]
> http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
> .
>

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