Version 3.1.0 of the streaming percentiles library has been released. The streaming percentiles library is a cross-platform, multi-language (C++ and JavaScript) implementation of a number of online (single-pass) percentile algorithms. This version of the streaming percentiles library adds support for copy construction, assignment, move construction, and move assignment on all analytics classes. This change allows you to put streaming analytics classes into STL containers, such as: #include <vector>#include <stmpct/gk.hpp> std::vector<stmpct::gk<double>> algs; algs.

This is part 8 of my series on calculating percentiles on streaming data. As mentioned in part 6 of this series, I have published a C++ and JavaScript library which implements a number of streaming percentile algorithms on GitHub at https://github.com/sengelha/streaming-percentiles. Versions 1.x and 2.x of the C++ library required all measurements to use the type double, and usage of the algorithms looked something like this: #include <stmpct/gk.hpp> double epsilon = 0.

I have decided to move my link aggregation efforts, such as they are, to Bitly, and to leave this blog for original content. Follow me on Twitter if you’re interested in tracking these links in the future.

In a previous blog post, I described how I took Emscripten-created JS and turned it into an UMD module. One of the reasons I did this was because I wanted more control over the generated JavaScript and for it to be usable in more contexts, such as with the RequireJS module loader. As I am a responsible developer, I desired to create a number of automated unit tests to ensure that the client-visible API for my Emscripten module works as I intended.

By default, Emscripten creates a module which can be used from both Node.JS and the browser, but it has the following issues: The module pollutes the global namespace The module is created with the name Module (in my case, I require streamingPercentiles) The module cannot be loaded by some module loaders such as require.js While the above issues can (mostly) be corrected by using –s MODULARIZE=1, it changes the semantics of the resulting JavaScript file, as the module now returns a function rather than an object.

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This is part 7 of my series on calculating percentiles on streaming data. In 2005, Graham Cormode, Flip Korn, S. Muthukrishnan, and Divesh Srivastava published a paper called Effective Computation of Biased Quantiles over Data Streams [CKMS05]. This paper took the Greenwald-Khanna algorithm [GK01] and made the following notable changes: Generalized the algorithm to work with arbitrary targeted quantiles, where a targeted quantile is a combination of a quantile $\phi$ and a maximum allowable error $\epsilon$.

This is part 6 of my series on calculating percentiles on streaming data. For the past 10 days or so, I’ve been working on the build process of my C++ and JavaScript streaming analytics libraries. Using the magic of Emscripten, I have been able to combine both libraries into a single, C++ codebase, from which I can compile both the C++ and JavaScript versions of the library. Furthermore, I was able to do this without breaking backwards compatibility of the JavaScript library.

This is part 5 of my series on calculating percentiles on streaming data. I have created a reusable C++ library which contains my implementation of the streaming percentile algorithms found within this blog post and published it to GitHub. Here’s what using it looks like: #include <stmpct/gk.hpp> using namespace stmpct; double epsilon = 0.1; gk g(epsilon); for (int i = 0; i < 1000; ++i) g.insert(rand()); double p50 = g.quantile(0.5); // Approx.

This is part 4 of my series on calculating percentiles on streaming data. I have created a reusable JavaScript library which contains my implementation of the streaming percentile algorithms found within this blog post and published it to GitHub and NPM. Here’s what using it looks like: var sp = require("streaming-percentiles'); // epsilon is allowable error. As epsilon becomes smaller, the // accuracy of the approximations improves, but the class consumes // more memory.