I successfully indexed a collection using Galago. I didn't found any parameter for removing stopwords for indexing. Does galago remove stopwords automatically? If no, how can I pass the stopwords list to Galago and how I can tell Galago to remove stopwords?
Galago, as a research search engine, tries not to make assumptions that can't be taken back: by default, indexes are built for stemmed and unstemmed terms.
During index time, no stopwords are removed, putting the burden on you at query-time, but which allows for changing or tuning stopword lists on a training set.
If you want stopword removal, it needs to be a query-time step. If you think about it, this is what any modern search engine wants unless cramped for disk space: the query "to be or not to be" is unanswerable without stopwords or more sophisticated techniques, but it is better to write some code that will remove stopwords unless it empties the query than to remove them unconditionally.
Galago provides access to the "inquery" stopword list through the WordLists class.
Related
I have a few XML documents in marklogic which have the structure
<abc:doc>
<abc:doc-meta>
<abc:meetings>
<abc:meeting>
</abc:meeting>
<abc:meeting>
</abc:meeting>
</abc:meetings>
</abc:doc-meta>
</abc:doc>
We can have more than one <abc:meeting> element under the <abc:meetings> element.
I am trying to write a cts:search query to get only documents that have more than one <abc:meeting> element in the document.
Please advise
This is tricky. Ideally, you'd want to drive searches from indexes for best performance. Unfortunately, MarkLogic doesn't keep track of element counts in its universal index, and aggregating counts from a range index can be cumbersome.
The overall simplest solution would be to add a count attribute on abc:meetings, and then add a range index on that. It does mean you'd have to change your data, and you'd have to keep that attribute in synch with each change.
You could also just search on the presence of abc:meeting with cts:element-query(), and append an XPath predicate to count the number of elements afterwards. Something like:
cts:search(
collection(),
cts:element-query(xs:QName('abc:meeting'), cts:true-query())
)[count(.//abc:meeting) > 1]
If not many documents contain meetings, this might work fairly well for you, but it still requires pulling up all documents containing meetings, hence could be expensive.
I played with the thought of leveraging cts:near-query(), but that is driven on word positions, so depends on the actual amount of tokens inside a meeting. If that were always an exact number of tokens (unlikely I'd guess), you could use the minimal-distance option on a double cts:element-query() wrapped in a cts:near-query(). It might help optimize the previous option a little though.
Most performant option I can think of right now, involves adding a User-Defined aggregate Function. It unfortunately means compiling c++ code. I happen to have written such a UDF in the past, that you should be able to use as-is after compilation and installation. For details see:
https://github.com/grtjn/doc-count-udf
and
http://docs.marklogic.com/guide/app-dev/aggregateUDFs
HTH!
It boils down to how many "a few" is. If it's thousands or fewer, than what grtjn presents above for a cts:search plus an XPath expression will work fine. If it's more, I'd add the count attribute to abc:meetings and then use a pre-commit trigger (e.g. on the collection of these documents) to ensure that the count attribute value is kept in sync. You'd need a range index to be able to query for "Documents that have a count of meetings of 2 or greater".
Of course, if all you need to query on is whether there's more than one meeting, then just add a "multiple" attribute to abc:meetings with a value of "true". Then you don't need a range index - you can do a cts:element-attribute-value-query on abc:meetings and multiple="true".
It's a Drupal site with solr for search. Mainly I am not satisfied with current search result on Chinese. The tokenizer has broken the words into supposed small pieces. Most of them are reasonable. But still, it made mistakes by not treating something as a valid token either breaking it to pieces or not breaking it.
Assuming I am writing Chinese now: big data analysis is one word which shouldn't be broken. So my search on it should find it. Also I want people to find AI and big data analysis training as the first hit when they search the exact phrase AI and big data analysis training.
So I want a way to intervene or compensate the current tokens to make the search smarter.
Maybe there is a file in solr allow me to manually write these tokens down to relate them certain phrases? So every time when indexing, solr can use it as a reference.
You different steps to achieve what you want :
1) I don't see an extremely big problem with your " over tokenization" :
big data analysis is one word which shouldn't be broken. So my search on it should find it. -> your search will find it even if tokenized, I understand this was an example and the actual words are chinese, but I suspect a different issue there
2) You can use the edismax[1] query parser with phrase boost at various level to boost subsequent tokens or phrases ( pf,pf2,pf3...ps,ps2,ps3...)
[1] https://lucene.apache.org/solr/guide/6_6/the-extended-dismax-query-parser.html , https://lucene.apache.org/solr/guide/6_6/the-extended-dismax-query-parser.html#TheExtendedDisMaxQueryParser-ThepsParameter
I need to recognize a complex chemichal names from a scanned document (pdf). They contain special characters and are written in a table format. I also have an Excel document that contains ALL possible names (I would say rows because there are no combinations) that I may encounter during scanning. Is there a way to create ligatures (so the Finereader will recognize an entire row instead of dissecting it into separate characters)? I tried creating a user dictionary but Finereader does not treat it as a one row.
The only way to create ligatures is to use "user pattern training". In FineReader, go to Tools -> Options -> Read tab (changes slightly depending on FR version) and enable User pattern training. During training extend your box to include several combined characters, thus creating a ligature.
The formulas recognition using this method is tough but may be possible.
I have done this many times in my work at www.wisetrend.com. I am a former ABBYY support employee and current integrator and OCR consulting specialist. I will be glad to help if you need more specific assistance.
How to handle misspelled words in Watson conversation API. NLP technique/Algorithm used in converation API calculates the word ranking and matches the trained data based on the rank.But how to handle the mispelled words or the short names in english.
At the moment there is nothing special to handle misspellings. The best process is to use the 'Synonyms' option within entities to add what you expect the user to use, including misspellings, short names, and acronym's.
I am working on Marklogic tool
I am having a database of around 27000 documents.
What I want to do is retrieve the keywords which have maximum frequency in the documents given by the result of any search query.
I am currently using xquery functions to count the frequency of each word in the set of all documents retrieved as query result. However, this is quite inefficient.
I was thinking that it would help me if i could get the list of words on which marklogic has performed indexing.
So is there a way to retrieve the list of indexed words from the universal index of marklogic??
Normally you would use something like this in MarkLogic:
(
for $v in cts:element-values(xs:Qname("myelem"))
let $f := cts:frequency($v)
order by $f descending
return $v
)[1 to 10]
This kind of functionality is built-in in the search:search library, which works very conveniently.
But you cannot use that on values from cts:words e.a. unfortunately. There is a little trick that could get you close though. Instead of using cts:frequency, you could use a xdmp:estimate on a cts:search to get a fragment count:
(
for $v in cts:words()
let $f := xdmp:estimate(cts:search(collection(), $v))
order by $f descending
return $v
)[1 to 10]
The performance is less, but still much faster than bluntly running through all documents.
HTH!
What if your search contains multiple terms? How will you calculate the order?
What if some of your terms are very common in your corpus of documents, and others are very rare? Should the count of "the" contribute more to the score than "protease", or should they contribute the same?
If the words occur in the title vs elsewhere in the document, should that matter?
What if one document is relatively short, and another is quite long. How do you account for that?
These are some of the basic questions that come up when trying to determine relevancy. Most search engines use a combination of term frequency (how often do the terms occur in your documents), and document frequency (how many documents contain the terms). They can also use the location of the terms in your documents to determine a score, and they can also account for document length in determining a score.
MarkLogic uses a combination of term frequency and document frequency to determine relevance by default. These factors (and others) are used to determine a relevance score for your search criteria, and this score is the default sorting for results returned by search:search from the search API or the low-level cts:search and its supporting operators.
You can look at the details of the options for cts:search to learn about some of the different scoring options. See 'score-logtfidf' and others here:
http://community.marklogic.com/pubs/5.0/apidocs/SearchBuiltins.html#cts:search
I would also look at the search developers guide:
http://community.marklogic.com/pubs/5.0/books/search-dev-guide.pdf
Many of the concepts are under consideration by the XQuery working group as enhancements for a future version of XQuery. They aren't part of the language today. MarkLogic has been at the forefront of search for a number of years, so you'll find there are many features in the product, and a lot of discussion related to this area in the archives.
"Is there a way to retrieve the list of indexed words from the universal index of marklogic?" No. The universal index is a hash index, so it contains hashes not words.
As noted by others you can create value-based lexicons that can list their contents. Some of these also include frequency information. However, I have another suggestion: cts:distinctive-terms() will identify the most distinctive terms from a sequence of nodes, which could be the current page of search results. You can control whether the output terms are just words, or include more complex terms such as element-word or phrase. See the docs for more details.
http://docs.marklogic.com/5.0doc/docapp.xqy#display.xqy?fname=http://pubs/5.0doc/apidoc/SearchBuiltins.xml&category=SearchBuiltins&function=cts:distinctive-terms
I have used cts:distinctive-terms(). It gives mostly wildcarded terms in my case which are not of much use. Furthur it is suitable for finding distinctive terms in a single document. When I try to run it on many documents it is quite slow.
What I want to implement is a dynamic facet which is populated with the keywords of the documents which come up in the search result. I have implemented it but it is inefficient as it counts the frequency of all the words in the documents. I want it to be a suggestion or recommandation feature like if you have searched for this particular term or phrase then you may be interested in these suggested terms or phrases. So I want an efficient method to find the terms which are common in the result set of documents of a search.
I tried cts:words() as suggested. It gives similar words as the search query word and the number of documents in which it is contained. WHat it does not take into account is the set of search result documents. It just shows the number of documents which contain similar words in the whole database, irrespective of whether these documents are present in the search result or not