Hi Aleksander, With all the help of you and the other comments, we're now at a point where a MoreLikeThis list is returned, and shows 10 related records. However on the query executed there are no keywords whatsoever being returned. Is the querystring still wrong or is something else required?
The querystring we're currently executing is: http://suempnr3:8080/solr/select/?q=amsterdam&mlt.fl=text&mlt.displayTerms=list&mlt=true Best, Patrick -----Original Message----- From: Aleksander M. Stensby [mailto:[EMAIL PROTECTED] Sent: woensdag 26 november 2008 15:07 To: solr-user@lucene.apache.org Subject: Re: Keyword extraction Ah, yes, That is important. In lucene, the MLT will see if the term vector is stored, and if it is not it will still be able to perform the querying, but in a much much much less efficient way.. Lucene will analyze the document (and the variable DEFAULT_MAX_NUM_TOKENS_PARSED will be used to limit the number of tokens that will be parsed). (don't want to go into details on this since I haven't really dug through the code:p) But when the field isn't stored either, it is rather difficult to re-analyze the document;) On a general note, if you want to "really" understand how the MLT works, take a look at the wiki or read this thorough blog post: http://cephas.net/blog/2008/03/30/how-morelikethis-works-in-lucene/ Regards, Aleksander On Wed, 26 Nov 2008 14:41:52 +0100, Plaatje, Patrick <[EMAIL PROTECTED]> wrote: > Hi Aleksander, > > This was a typo on my end, the original query included a semicolon > instead of an equal sign. But I think it has to do with my field not > being stored and not being identified as termVectors="true". I'm > recreating the index now, and see if this fixes the problem. > > Best, > > patrick > > -----Original Message----- > From: Aleksander M. Stensby [mailto:[EMAIL PROTECTED] > Sent: woensdag 26 november 2008 14:37 > To: solr-user@lucene.apache.org > Subject: Re: Keyword extraction > > Hi there! > Well, first of all i think you have an error in your query, if I'm not > mistaken. > You say http://localhost:8080/solr/select/?q=id=18477975... > but since you are referring to the field called "id", you must say: > http://localhost:8080/solr/select/?q=id:18477975... > (use colon instead of the equals sign). > I think that will do the trick. > If not, try adding the &debugQuery=on at the end of your request url, > to see debug output on how the query is parsed and if/how any > documents are matched against your query. > Hope this helps. > > Cheers, > Aleksander > > > > On Wed, 26 Nov 2008 13:08:30 +0100, Plaatje, Patrick > <[EMAIL PROTECTED]> wrote: > >> Hi Aleksander, >> >> Thanx for clearing this up. I am confident that this is a way to >> explore for me as I'm just starting to grasp the matter. Do you know >> why I'm not getting any results with the query posted earlier then? >> It gives me the folowing only: >> >> <lst name="moreLikeThis"> >> <result name="18477975" numFound="0" start="0"/> </lst> >> >> Instead of delivering details of the interestingTerms. >> >> Thanks in advance >> >> Patrick >> >> >> -----Original Message----- >> From: Aleksander M. Stensby [mailto:[EMAIL PROTECTED] >> Sent: woensdag 26 november 2008 13:03 >> To: solr-user@lucene.apache.org >> Subject: Re: Keyword extraction >> >> I do not agree with you at all. The concept of MoreLikeThis is based >> on the fundamental idea of TF-IDF weighting, and not term frequency >> alone. >> Please take a look at: >> http://lucene.apache.org/java/2_4_0/api/org/apache/lucene/search/simi >> l ar/MoreLikeThis.html As you can see, it is possible to use cut-off >> thresholds to significantly reduce the number of unimportant terms, >> and generate highly suitable queries based on the tf-idf frequency of >> the term, since as you point out, high frequency terms alone tends to >> be useless for querying, but taking the document frequency into >> account drastically increases the importance of the term! >> >> In solr, use parameters to manipulate your desired results: >> http://wiki.apache.org/solr/MoreLikeThis#head-6460069f297626f2a982f1e >> 2 >> 2ec5d1519c456b2c >> For instance: >> mlt.mintf - Minimum Term Frequency - the frequency below which terms >> will be ignored in the source doc. >> mlt.mindf - Minimum Document Frequency - the frequency at which words >> will be ignored which do not occur in at least this many docs. >> You can also set thresholds for term length etc. >> >> Hope this gives you a better idea of things. >> - Aleks >> >> On Wed, 26 Nov 2008 12:38:38 +0100, Scurtu Vitalie >> <[EMAIL PROTECTED]> >> wrote: >> >>> Dear Partick, I had the same problem with MoreLikeThis function. >>> >>> After briefly reading and analyzing the source code of moreLikeThis >>> function in solr, I conducted: >>> >>> MoreLikeThis uses term vectors to ranks all the terms from a >>> document by its frequency. According to its ranking, it will start >>> to generate queries, artificially, and search for documents. >>> >>> So, moreLikeThis will retrieve related documents by artificially >>> generating queries based on most frequent terms. >>> >>> There's a big problem with "most frequent terms" from documents. >>> Most frequent words are usually meaningless, or so called function >>> words, or, people from Information Retrieval like to call them >>> stopwords. >>> However, ignoring technical problems of implementation of >>> moreLikeThis function, this approach is very dangerous, since >>> queries are generated artificially based on a given document. >>> Writting queries for retrieving a document is a human task, and it >>> assumes some knowledge (user knows what document he wants). >>> >>> I advice to use others approaches, depending on your expectation. >>> For example, you can extract similar documents just by searching for >>> documents with similar title (more like this doesn't work in this >>> case). >>> >>> I hope it helps, >>> Best Regards, >>> Vitalie Scurtu >>> --- On Wed, 11/26/08, Plaatje, Patrick >>> <[EMAIL PROTECTED]> >>> wrote: >>> From: Plaatje, Patrick <[EMAIL PROTECTED]> >>> Subject: RE: Keyword extraction >>> To: solr-user@lucene.apache.org >>> Date: Wednesday, November 26, 2008, 10:52 AM >>> >>> Hi All, >>> as an addition to my previous post, no interestingTerms are returned >>> when i execute the folowing url: >>> http://localhost:8080/solr/select/?q=id=18477975&mlt.fl=text&mlt.int >>> e r es tingTerms=list&mlt=true&mlt.match.include=true >>> I get a moreLikeThis list though, any thoughts? >>> Best, >>> Patrick >>> >>> >>> >>> >>
