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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Generating grids in javascript
Recently I find some of my pet projects share a common pattern, they all are based on some kind of grids. So I find myself writing similar piece of code over and over again. While re-inventing wheels is quite fun, especially when you learn new way of getting things done with every iteration, it is actually quite tedious after a while.
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Picking Up Category Theory (and eventually Haskell)
I don’t quite remember when did I first heard about Category Theory, but the term stuck in my head for quite a while. Eventually I attempted to start looking for tutorials on the topic, but it is hard to find one that I actually understand. Most of them are either leaning too much to the Mathematics side, or too much to the Programming side.
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Setting Up Virtuoso for Redland Under Ubuntu
Just a quick update to the previous post, the virtuoso storage engine works with redland provided the required packages are properly installed (yes, yes, yes, I know I haven’t release my PHP OO wrapper for Redland). Now that the package is installed, we need to do some configuration so that Redland can use it.
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Building a simple ASGI Websocket Application
Getting comfortable to asyncio takes a bit of practice, so I revisited a practice project I did when I was working for my previous company. Suppose I want to build a very simple websocket application, without use of any web application library/framework. In order to keep it simple, I also opt to just build the frontend with minimal setup (just plain ES6 without webpack/vite).
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Creating a new daemon script for Meego 1.2 Harmattan
Call me a cheapskate, as I still have not subscribe to a mobile data plan after purchasing my second smartphone, namely Nokia N9. There’s this ‘allow background connections’ option but it doesn’t care whether the connected network is a WLAN network or mobile data network. After finding out that Nokia has no interest in creating another separate option so that each type of network has their respective ‘allow background connections’ switch, I decided to make one for my own.
