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From Mark <static.void....@gmail.com>
Subject Re: Percolate feature?
Date Sat, 10 Aug 2013 22:24:08 GMT
> So to reiteratve your examples from before, but change the "labels" a 
> bit and add some more converse examples (and ignore the "highlighting" 
> aspect for a moment...
> 
> doc1 = "Sony"
> doc2 = "Samsung Galaxy"
> doc3 = "Sony Playstation"
> 
> queryA = "Sony Experia"       ... matches only doc1
> queryB = "Sony Playstation 3" ... matches doc3 and doc1
> queryC = "Samsung 52inch LC"  ... doesn't match anything
> queryD = "Samsung Galaxy S4"  ... matches doc2
> queryE = "Galaxy Samsung S4"  ... matches doc2
> 
> 
> ...do i still have that correct?

Yes

> 2) if you *do* care about using non-trivial analysis, then you can't use 
> the simple "termfreq()" function, which deals with raw terms -- in stead 
> you have to use the "query()" function to ensure that the input is parsed 
> appropriately -- but then you have to wrap that function in something that 
> will normalize the scores - so in place of termfreq('words','Galaxy') 
> you'd want something like...


Yes we will be using non-trivial analysis. Now heres another twist… what if we don't care
about scoring?


Let's talk about the real use case. We are marketplace that sells products that users have
listed. For certain popular, high risk or restricted keywords we charge the seller an extra
fee/ban the listing. We now have sellers purposely misspelling their listings to circumvent
this fee. They will start adding suffixes to their product listings such as "Sonies" knowing
that it gets indexed down to "Sony" and thus matching a users query for Sony. Or they will
munge together numbers and products… "2013Sony". Same thing goes for adding crazy non-ascii
characters to the front of the keyword "Î’Sony". This is obviously a problem because we
aren't charging for these keywords and more importantly it makes our search results look like
shit. 

We would like to:

1) Detect when a certain keyword is in a product title at listing time so we may charge the
seller. This was my idea of a "reverse search" although sounds like I may have caused to much
confusion with that term.
2) Attempt to autocorrect these titles hence the need for highlighting so we can try and replace
the terms… this of course done outside of Solr via an external service.

Since we do some stemming (KStemmer) and filtering (WordDelimiterFilterFactory) this makes
conventional approaches such as regex quite troublesome. Regex is also quite slow and scales
horribly and always needs to be in lockstep with schema changes.

Now knowing this, is there a good way to approach this?

Thanks


On Aug 9, 2013, at 11:56 AM, Chris Hostetter <hossman_lucene@fucit.org> wrote:

> 
> : I'll look into this. Thanks for the concrete example as I don't even 
> : know which classes to start to look at to implement such a feature.
> 
> Either roman isn't understanding what you are aksing for, or i'm not -- 
> but i don't think what roman described will work for you...
> 
> : > so if your query contains no duplicates and all terms must match, you can
> : > be sure that you are collecting docs only when the number of terms matches
> : > number of clauses in the query
> 
> several of the examples you gave did not match what Roman is describing, 
> as i understand it.  Most people on this thread seem to be getting 
> confused by having their perceptions "flipped" about what your "data known 
> in advance is" vs the "data you get at request time".
> 
> You described this...
> 
> : >>>>> Product keyword:  "Sony"
> : >>>>> Product keyword:  "Samsung Galaxy"
> : >>>>> 
> : >>>>> We would like to be able to detect given a product title whether
or
> : >> not it
> : >>>>> matches any known keywords. For a keyword to be matched all of
it's
> : >> terms
> : >>>>> must be present in the product title given.
> : >>>>> 
> : >>>>> Product Title: "Sony Experia"
> : >>>>> Matches and returns a highlight: "<em>Sony</em> Experia"
> 
> ...suggesting that what you call "product keywords" are the "data you know 
> about in advance" and "product titles" are the data you get at request 
> time.
> 
> So your example of the "request time" input (ie: query) "Sony Experia" 
> matching "data known in advance (ie: indexed document) "Sony" would not 
> work with Roman's example.
> 
> To rephrase (what i think i understand is) your goal...
> 
> * you have many (10*3+) documents known in advance
> * any document D contain a set of words W(D) of varing sizes
> * any requests Q contains a set of words W(Q) of varing izes
> * you want a given request R to match a document D if and only if:
>   - W(D) is a subset of W(Q)
>   - ie: no iten exists in W(D) that does not exist in W(Q)
>   - ie: any number of items may exist in W(Q) that are not in W(D)
> 
> So to reiteratve your examples from before, but change the "labels" a 
> bit and add some more converse examples (and ignore the "highlighting" 
> aspect for a moment...
> 
> doc1 = "Sony"
> doc2 = "Samsung Galaxy"
> doc3 = "Sony Playstation"
> 
> queryA = "Sony Experia"       ... matches only doc1
> queryB = "Sony Playstation 3" ... matches doc3 and doc1
> queryC = "Samsung 52inch LC"  ... doesn't match anything
> queryD = "Samsung Galaxy S4"  ... matches doc2
> queryE = "Galaxy Samsung S4"  ... matches doc2
> 
> 
> ...do i still have that correct?
> 
> 
> A similar question came up in the past, but i can't find my response now 
> so i'll try to recreate it ...
> 
> 
> 1) if you don't care about using non-trivial analysis (ie: you don't need 
> stemming, or synonyms, etc..), you can do this with some 
> really simple function queries -- asusming you index a field containing 
> hte number of "words" in each document, in addition to the words 
> themselves.  Assuming your words are in a field named "words" and the 
> number of words is in a field named "words_count" a request for something 
> like "Galaxy Samsung S4" can be represented as...
> 
>  q={!frange l=0 u=0}sub(words_count,
>                         sum(termfreq('words','Galaxy'),
>                             termfreq('words','Samsung'),
>                             termfreq('words','S4'))
> 
> ...ie: you want to compute the sub of the term frequencies for each of 
> hte words requested, and then you want ot subtract that sum from the 
> number of terms in the documengt -- and then you only want ot match 
> documents where the result of that subtraction is 0.
> 
> one complexity that comes up, is that you haven't specified:
> 
>  * can the list of words in your documents contain duplicates?
>  * can the list of words in your query contain duplicates?
>  * should a document with duplicatewords match only if the query also 
> contains the same word duplicated?
> 
> ...the answers to those questions make hte math more complicated (and are 
> left as an excersize for the reader)
> 
> 
> 2) if you *do* care about using non-trivial analysis, then you can't use 
> the simple "termfreq()" function, which deals with raw terms -- in stead 
> you have to use the "query()" function to ensure that the input is parsed 
> appropriately -- but then you have to wrap that function in something that 
> will normalize the scores - so in place of termfreq('words','Galaxy') 
> you'd want something like...
> 
>            if(query({!field f=words v='Galaxy'}),1,0)
> 
> ...but again the math gets much harder if you make things more complex 
> with duplicate words i nthe document or duplicate words in the query -- you'd 
> probably have to use a custom similarity to get the scores returned by the 
> query() function to be usable as is in the match equation (and drop the 
> "if()" function)
> 
> 
> As for the highlighting part of hte problme -- that becomes much easier -- 
> independent of the queries you use to *match* the documents, you can then 
> specify a "hl.q" param to specify a much simpler query just containing the 
> basic lst of words (as a simple boolean query, all clouses optional) and 
> let it highlight them in your list of words.
> 
> 
> 
> 
> 
> 
> 
> -Hoss


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