Ahhh it all makes sense to me now :-)
-----Original Message-----
From: Erik Hatcher [mailto:[EMAIL PROTECTED]
Sent: 09 February 2007 12:01
To: [email protected]
Subject: Re: categorisation
On Feb 9, 2007, at 5:40 AM, Kainth, Sachin wrote:
> It makes sense to me only if you tell me that all the bits in the
> BitSet "all" will be 1.
well, ok, so the "all" may be misleading. call it queryBits instead
then :)
"all" means *all documents that match the query*, though.
it wouldn't make sense to AND a bitset with one that is all 1's always.
Erik
>
> -----Original Message-----
> From: Erik Hatcher [mailto:[EMAIL PROTECTED]
> Sent: 08 February 2007 18:37
> To: [email protected]
> Subject: Re: categorisation
>
>
> On Feb 8, 2007, at 12:36 PM, Kainth, Sachin wrote:
>
>> Chris has given an example of how to perform categorisation of lucene
>> searches:
>>
>> String[] mfgs = ...;
>> String query = "+category:cameras +price:[0 to 10]";
>> Query q = QueryParser.parse(query);
>> Hits results = searcher.search(q, mySort)
>> BitSet all = (new QueryFilter(q)).bits(reader)
>> int[] mfg_counts = new int[mfgs.length];
>> for i in (0 to mfgs.length) {
>> BitSet these = (new QueryFilter(new TermQuery("mfg",mfgs
>> [i]))).bits(reader);
>> these.and(all)
>> mfg_counts[i] = these.cardinality();
>> }
>>
>> What I don't understand though is what this line does:
>>
>> BitSet all = (new QueryFilter(q)).bits(reader)
>>
>> Anyone have any ideas?
>
> "all" is a BitSet lit up for the documents that matched "query".
> "these" (the BitSet for a particular category) is .anded with "all"
> to get the counts _left over_ for each category given "query".
>
> Make sense?
>
> Erik
>
>
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