I already read the rocksdb overview, but i can't find "how many parameters used in rocksdb"
where can I find that?
There isn't any explicit count on how many rocksdb options are used. You can check table.h, options.h, advanced_options.h to find out about the options.
Related
I try to find details about the filtering methods that are mentioned here:
https://mlr3book.mlr-org.com/list-filters.html#list-filters
https://mlr3filters.mlr-org.com/
Unfortunately, I could not find more detailed information, e.g. how is information_gain calculated and what parameter can I set.
Where do I find details about this?
You can have a look at the function references and check the underlying R functions which are wrapped by {mlr3filters} and their respective help pages.
where is the document about gremlin with step?
https://tinkerpop.apache.org/docs/current/reference/#with-step
https://tinkerpop.apache.org/javadocs/current/full/org/apache/tinkerpop/gremlin/process/computer/traversal/step/map/ShortestPath.html
there is no example I can use.
I want to know all with-step option(like ShortestPath.edges-Direction.OUT) for shortestPath().
I found below
g.withComputer().V(xxx).shortestPath().with(ShortestPath.edges, Direction.OUT).with(ShortestPath.distance, 'cost').with(ShortestPath.target, hasId(bbb))
I want to know all option I can use
The with()-step is not really a "step". It is a step modulator. Its context is bound to the step that it is modifying and therefore you won't find "all the with() configurations" in one place. You can only find them in the documentation related to the steps that they modulate. Using shortestPath() as an example, note that if you look at the shortestPath() step documentation all of the options are present.
You may also need to consult the documentation of your graph provider as they may provide their own configuration keys for certain steps which can help optimize or otherwise modify traversal operations.
The line: g.V('1').out('knows').hasId('2').hasNext()
This exact line works in the Gremlin console.
I have not read in the documentation that hasNext does not exist in Gremlin.NET. Am I missing something, or is there simply another way to do this in Gremlin.NET?
This method is really missing in Gremlin.Net right now. While this is not explicitly stated in the documentation, the documentation does list all terminal steps implemented by Gremlin.Net:
ITraversal.Next()
ITraversal.NextTraverser()
ITraversal.ToList()
ITraversal.ToSet()
ITraversal.Iterate()
hasNext is also such a terminal step but as you can see it is missing in this list.
The only workaround I can think of for situations like this is to use the count step and then check in your application whether the returned count is greater than zero:
var count = g.V("1").Out("knows").HasId("2").Count().Next();
var exists = count > 0;
In some cases it could also make sense to limit the number of vertices going into the Count step as you aren't interested in the exact count but only want to know whether at least one vertex exists:
g.V("1").Out("knows").HasId("2").Limit<Vertex>(1).Count().Next();
This is also the proposed workaround in the ticket for this feature: TINKERPOP-1921.
It does not exist yet:
https://issues.apache.org/jira/browse/TINKERPOP-1921
The main reason is related to the fact that hasNext() is a Java Iterator semantic that was not applied to .NET. Gremlin Language Variants (GLVs) like .NET are given some latitude in terms of how they interpret the language so as to provide the most at-home feel for developers using it. In other words, if you are using the .NET GLV you shouldn't feel as though you are coding in Java, but should instead feel write at home with the standard .NET semantics.
That said, it could be argued, as it is in the issue I've referenced above, that something like hasNext() is a common form of Gremlin as a query language and should thus be available in all GLVs. So, we will consider those options as we come across them.
For .NET I guess you would try to check Current as discussed here.
I looked into the rocksDB source code but I was unable to find the implementation of the open function for DB.
Ex: rocksdb::DB::Open(options, "/tmp/testdb", &db);
If I get the source or explanation it would be helpful.
The implementation of rocksdb's rocksdb::DB is spread across multiple sources. It is declared in include/rocksdb/db.h, but implemented in multiple files starting with db_impl in db/. The one you are looking for is db_impl_open.cc: https://github.com/facebook/rocksdb/blob/master/db/db_impl_open.cc.
I thought this was asked before, but 15 minutes of searching on Google and the site search didn't turn anything up...so:
Where can I obtain free (as in beer and/or as in speech) dictionary files? I'm mainly interested in English, but if you know of any dictionary files, please point them out.
Note: This question doesn't have a right/wrong answer, so I made it community-wiki. However, I feel that it might be valuable to not only myself, but anyone who wishes to implement or use a spell checker with various dictionary files.
I have found a SourceForge project called Word List, which appears to have a number of dictionaries. I have downloaded a couple and am currently checking them out.
On Linux you can look in places like /usr/share/dict/words
I would presume that OpenOffice contains dictionaries for several languages.
I don't know what your target platform is but here is a solution that is for VB.NET. It uses the Office libraries which Office in itself isn't free but if your users are all internal and have Office then you could leverage these libs. There is a zip file with the example source code you can download as well.
Check spelling and grammar
There is what appears to be a half-decent dictionary available for free here on CodeProject.com (registration required unfortunately).