Yes, surely you can boost the inverted "distance", it is the simplest
formula for such a boost. My formula does almost the same thing, only with
configurable coefficient, plus it treats items with large "distance" almost
the same (so, it heavily boosts only items, created within a few recent
days).
As for incremental indexing, I use it as well, and it's not so easy to deal
with it. I use the following method:
During incremental indexing, I take the date of latest full indexing as a
basis and boost all newly created items in a way that all of them have
higher date boost than those already indexed (the greater is the "distance"
between last indexing date and now, the bigger is the boost value). So,
date boost value increases and increases until I run full indexing again,
which normalizes the date boost of all items. This method works only if you
run full indexing rather frequently, once a few days or at least once a
week. Otherwise, date boost would quickly become too big and thus will
overshadow other boosts, that might decrease overall search relevance.
Regards,
Pavlo Zahozhenko
On Tue, Dec 22, 2009 at 1:58 PM, Robert Pohl <[email protected]> wrote:
> Thanks Pavlo!
>
> And yes, I use incremental indexing =)
> I have a create date, but can I boost the (inverted) "distance" between
> DateTime.Now and CreateDate?
>
> That is, boost the most with dates that have the lowest distance.
>
> Thanks,
> Rob
>
>
>
> Pavlo Zahozhenko wrote:
>
>> You can analyze creation date of each indexed item and boost the resulting
>> Lucene documents accordingly. For example, I'm using the following
>> formula:
>> " dateBoost = 1 + (DateBoostCoeff - 1)/(distance.TotalDays + 1) ", where
>> distance.TotalDays is the difference in days between DateTime.Today and
>> item
>> creation date. Then simply " doc.SetBoost(dateBoost) ". This formula fits
>> my
>> needs, but you'll probably have to experiment with different formulas a
>> bit
>> to find out what fits your model.
>>
>> Now all this gets much more complex if you're using incremental indexing,
>> but there's a solution for it as well.
>>
>> Regards,
>> Pavlo Zahozhenko
>>
>> On Tue, Dec 22, 2009 at 1:18 PM, Robert Pohl <[email protected]> wrote:
>>
>>
>>
>>> Hi all,
>>>
>>> Is there a way to boost index position?
>>> I want to achieve a result that is basically sorted by the latest (added
>>> to
>>> the index) on top, as well as text relevance.
>>> For example I search for tiger woods, and don't want articles from last
>>> year (in the first places).
>>>
>>> Thanks,
>>> Rob
>>>
>>>
>>>
>>>
>>
>>
>>
>
>
