Notes on codes, projects and everything
Information Retrieval
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Further Hack on the Multi-Dimensional Approximate Neighbour Search
Traversing a tree structure often involves writing a recursive function. However, Python isn’t the best language for this purpose. Therefore I started flattening the tree into a key-value dictonary structure. Logically it is still a tree, but it is physically stored as a dictionary. Therefore it is now easier to write a simple loop to traverse it.
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Approximate Neighbour Search in Multiple Dimensions
In the previous post, I re-implemented Annoy in 2D with some linear algebra maths. Then I spent some time going through some tutorial on vectors, and expanded the script to handle data in 3D and more. So instead of finding gradient, the perpendicular line in the middle of two points, I construct a plane, and find the distance between it and points to construct the tree.
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Re-implementing Approximate Nearest Neighbour Search
Recently I switched my search code to Annoy because the input dataset is huge (7.5mil records with 20k dictionary count). It wasn’t without issues though, however I would probably talk about it next time. In order to figure out what each parameters meant, I spent some time watching through the talk given by the author @fulhack.
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Information Retrieving with ….. a lot of libraries
Implementing a Information Retrieval system is a fun thing to do. However, doing it efficiently is not (at least to me). So my first few attempts didn’t really end well (mostly uses just Go/golang with some bash tricks here and there, with or without a database). Then I jumped back to Python, which I am more familiar with and was very surprised with all the options available. So I started with Pandas and Scikit-learn combo.
Random Posts
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Revisiting semantic web (plus wheel building with Poetry)
Back then, when I was still working on my postgraduate degree research, I used RDF, which was the preferred format in the world of Semantic Web to represent data. I eventually dropped the degree, and stopped following the development of the related technology and standards. Until I volunteered to update the import script for popit when I was looking for the next job/project.
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Spiraling Number
Back then in college, we were given a lot of programming practices. These questions usually shows a desired output format, and we were required to write a program to print out the exact thing. Usually it involves printing a matrix of numbers, or symbols etc. For these problems, usually a loop structure or two should solve the problem.
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Maintaining State with YUI Event
When one start writting Javascript in patterns like the module pattern, then sooner or later he would want to maintain the state when an event handler is called. The reason I am still using YUI to handle my event handling code is because I like how state can be maintained.
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Sync’ MP4 Tracks through MTP
I’m not sure why Windows Media Player 11 doesn’t like mp4/aac format but not being able to transfer my tracks in mp4 through MTP to my N81 really piss me off. At first I installed Songbird 1.0.0 to try synchronizing the tracks through the MTP addon but it doesn’t even play *.mp4 tracks out of the box under Windows XP SP3 (although it claimed otherwise). Weird thing happens when I was trying to synchronize anyway by having the files renamed to *.mp4 extension and it succeeded but without any meta-tag information.
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Building librdf-storage-virtuoso Package
I wanted to try using virtuoso as the storage engine for Redland but unfortunately there is no librdf-storage-virtuoso package for Ubuntu. After getting some help from @dajobe, I attempted to build the packages myself. Although it takes quite some time to build packages, but not too difficult it seems.
