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Topics /
Math & Algorithms
The most popular blog posts about math & algorithms on Hacker News. 89 posts.
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Why are roller coaster loops not circular?
Why are the loops on roller coasters never circular?
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How I created two images with the same MD5 hash
I posted the following images the other day which although looking totally different have exactly the same MD5 hash ( e06723d4961a0a3f950e...
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Why cans of soup are shaped the way they are
What is special about cylinders, and why do they have specific aspect ratios?
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Analysis of suspected MH370 pings recorded by Ocean Shield
So this is a bit of a deviation from my normal MATLAB oriented posts. In-fact MATLAB was not used once in this analysis! I've been followi...
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Zero Knowledge Proofs: An illustrated primer
One of the best things about modern cryptography is the beautiful terminology. You could start any number of punk bands (or Tumblrs) named after cryptography terms like ‘hard-core predicate&#…
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Elsevier journals – some facts
Update: figures now in from Imperial. See below. Further update: figures in from Nottingham too. Further update: figures now in from Oxford. Final update: figures in from LSE. A little over two yea…
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Levels of Excellence
Over on Google+, a computer scientist at McGill named Artem Kaznatcheev passed on this great description of what it’s like to learn math, written by someone who calls himself ‘man aft…
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Dual_EC_DRBG backdoor: a proof of concept
Dual_EC_DRBG is an pseudo-random number generator promoted by NIST in NIST SP 800-90A and created by NSA. This algorithm is problematic because it has been made mandatory by the FIPS norm (and should be implemented in every FIPS approved software) and some vendors even promoted this algorithm as first source of…
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Evolutionary algorithm to find Quake III's fast inverse square hack with Python
Curiosity killed the cat I've always been amazed by early game developers. Unlike today, they had to bend and twist software to its extre...
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Fast and easy Levenshtein distance using a trie (2011)
<img src="http://stevehanov.ca/blog/images/acer.jpg"/> If you have a web site with a search function, you will rapidly realize that most mortals are terrible typists. Many searches contain mispelled words, and users will expect these searches to magically work. This magic is often done using levenshtein distance. In…
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The Lambda Calculus for Absolute Dummies (2012)
If there is one highly underrated concept in philosophy today, it is computation . Why is it so important? Because computationalism is t...
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The most common errors in undergraduate mathematics
This page describes the errors that I have seen most frequently in undergraduate mathematics, the likely causes of those errors, and their remedies.
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The Traveling Salesman with Simulated Annealing, R, and Shiny
I built an interactive Shiny application that uses simulated annealing to solve the famous traveling salesman problem. You can play around with it to create and solve your own tours at the bottom of …
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How to Conquer Tensorphobia
A professor at Stanford once said, If you really want to impress your friends and confound your enemies, you can invoke tensor products… People run in terror from the $ \otimes$ symbol. He was explaining some aspects of multidimensional Fourier transforms, but this comment is only half in jest; people get confused by…
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Random Solutions are Often Good Enough
Sometimes taking the easy way out isn’t nearly as bad as it might seem! posted Thursday February 13th, 2014 Tagged: Math
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Helmhurts: Placing a WiFi router with the Helmholtz equation
A few posts back I was concerned with optimising the WiFi reception in my flat, and I chose a simple method for calculating the distribution of electromagnetic intensity. I casually mentioned that I really should be doing things more rigorously by solving the Helmholtz equation, but then didn't. Well, spurred on by a…
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How to be a Bayesian in Python
See also Frequentism and Bayesianism: A Python-driven Primer , a peer-reviewed article partially based on this content.
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The sum of all the positive integers is not -1/12
I haven't been blogging recently because my new startup is taking up all my time, but someone needs to stand up and say the emperor has no c...
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Categories from scratch
Note The latest version of this document can be found online at https://dr-knz.net/categories-from-scratch.html. Alternate formats: Source, PDF. Prologue The concept of category from mathematics happens to be useful to computer programmers in many ways. Unfortunately, all “good” explanations of categories so far have…