The latest blog posts to take off on Hacker News. 2,391 posts.
It’s fairly clear when one should buy a particular stock. One should buy stock when it is undervalued. What I have always wondered about is how much stock one should buy. A few months ago I stumbled upon the answer which is given by the Kelly criterion . It says that one should invest an amount to maximize one’s…
A handy rule of thumb for creating a confidence interval for the probability of an event you haven't seen happen yet.
I'd like to introduce a series of blog posts and their corresponding Python Notebooks gathering notes on the Deep Learning Book from Ian Goodfellow, Yoshua B...
Euler's identity seems baffling: It emerges from a more general formula: Yowza -- we're relating an imaginary exponent to sine and cosine! And somehow…
If you, like me, frequently commute via public transit, you may be familiar with the following situation:
Based on the description of the book in the World Scientific Press catalogue, I asked my university library to order a book entitled Automat...
Explaining how quaternions, a four-dimensional number system, describe 3d rotation.
Array and hash table are probably the most important data structures. Some programming languages such as Perl, Lua and Javascript, almost build the language core on top of the two data structures. …
Quaternions are used to represent an orientation in 3D space. This article attempts to demystify the complexities of quaternions.
The first rule of PAKE is: nobody ever wants to talk about PAKE. The second rule of PAKE is that this is a shame, because PAKE — which stands for Password Authenticated Key Exchange — is actually o…
As a developer, you have the power to change the world! You can write programs that enable new technologies. For instance, develop software to find an earlier diagnosis of diseases. But that’s not the only way. You might do it indirectly by creating projects that make people more productive and help them free up time…
I really like decision tables but they’ve fallen out of common knowledge. Let’s fix that. A decision table is a means of concisely representing branching and conditional computations. In the most basic form, you have some columns that represent the “inputs” as booleans and some columns that represent outputs and…
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I made a New Year's resolution: every plot I make during 2018 will contain uncertainty estimates. Nine months in and I have learned a lot, so I put together a summary of some of the most useful methods.
This is part one of a two-part article. Part two is here. A while back somebody told me to check out MiniZinc. Eventually I did and really enjoyed it, so figured I’d write about it here. This is actually going to be a two part article. Right now we’re talking about what it is and how it works, and in the next post…
The geometry puzzles that are lighting up Twitter.
Applying probabilistic models to data usually involves integrating a complex, multi-dimensional probability distribution. For example, calculating the expectation/mean of a model distribution invol…
Roughly speaking, Gödel’s Incompleteness Theorem states that there are true mathematical statements that cannot be proven. When I was in 11-th grade, my geometry teacher Mr. Olsen, my friend …
Reading maths textbooks linearly doesn't work; here's what to do instead.
Sometimes patterns can lead you astray. For example, it’s known that $latex \displaystyle{ \mathrm{li}(x) = \int_0^x \frac{dt}{\ln t} }$ is a good approximation to $latex \pi(x),$ the number …
It breaks my heart to write this post because the puzzle in question was 1) very expensive and 2) given to me by someone very dear to me who...
Back in the early 2000s, XML was all the rage. An unusual evolution from HTML, which itself was an evolution (devolution?) from SGML, XML w...
This incredible mathematical hat-trick is based on the paper Every positive integer is a sum of three palindromes by Javier Cilleruelo, Florian Luca and Lewis Baxter.
“To be wrong, or not to be wrong?” That is the wrong question. You are going to spend a lot of your time being wrong, especially if you become a scientist or mathematician. The question…
In this essay, after a brief review of the work we’ve already done on the Mockingbird, we’ll derive the Why Bird, known most famously as the Y Combinator . The why bird provides all the benefits of the mockingbird, but allows us to write more idiomatic JavaScript. We’ll see that one of the benefits of writing…
