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New
The latest blog posts to take off on Hacker News. 82 posts.
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Incremental Regular Expressions
This article was originally published in the Russian functional programming journal http://fprog.ru/ and this translation was intended to be published in Peter Seibel’s http://codequarterly.com/ journal, but as Peter eventually decided not to proceed with the journal, I am publishing it on my personal space.
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What does randomness look like?
On 13 June 1944, a week after the allied invasion of Normandy, a loud buzzing sound rattled through the skies of battle-worn London. The source of the sound was a newly developed German instrument …
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The Fast Fourier Transform
It’s often said that the Age of Information began on August 17, 1964 with the publication of Cooley and Tukey’s paper, “An Algorithm for the Machine Calculation of Complex Fourier…
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The Mathematical Hacker
The programming profession is blessed with a number of gifted essayists. Today I will pick on three of my favorites — Eric Raymond, Paul Graham, and Steve Yegge — because they all seem to disagree about why (and whether) mathematics is relevant to the practicing programmer. Their attitudes might be summarized as:
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Mona Lisa in 50 polygons, using a genetic algorithm (2008)
This weekend I decided to play around a bit with genetic programming and put evolution to the test, the test of fine art 🙂
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Making MathBox: Presentation-Quality Math with Three.js and WebGL
Presentation-quality math with Three.js and WebGL.
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Traveling Salesman: the most misunderstood problem
Whenever people start talking about NP-Complete problems, or even NP problems, one of the first examples they reach for is the classic Traveling Salesperson Problem. TSP makes sense because it int...
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The birthday paradox in action: calculating the probability of a hash collision
You may feel like you've seen this before. If you have, skip to the end where I talk about a formula, and discuss the relevance to parameters in computer hashing algorithms. In particular, I'm going to talk about how large hash spaces should be to avoid collisions with a given level of probability. If there are just…
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My IQ
Mathematics, applications of mathematics to life in general, and my life as a mathematician.
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Mastering Linear Algebra in 10 Days: Astounding Experiments in Ultra-Learning
The MIT Challenge My friend Scott Young recently finished an astounding feat: he completed all 33 courses in MIT’s fabled computer science curriculum, from Linear ... Read more
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A new kind of fractal?
Experimenting with the "divisibility" of complex numbers, I stumbled across this thingy. It looks like a fractal. Although the formula does not do any iterations. It reminds me of something. But I dont know what. Doing a Google image search brings up a couple of galaxies :) This image shows the region from (-1/-1) to…
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Google Earth Fractals
The following is a "photographic" gallery of fractal patterns found while exploring the planet with Google Earth. Each is provided with a KMZ file so the reader can explore the region for themselves. Readers are encouraged to submit their own discoveries for inclusion, credits will be included. Besides being examples…
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The game of life emulated in the game of life
Conway's Game of Life, emulated in Conway's Game of Life: The life simulator used is Golly which has a built-in script to generate these metapixel grids (select a pattern, and choose "metafier.py" from the scripts list). Outer Totalistic Cellular Automata Meta-Pixel: The metacell uses a period 184 tractor beam, which…
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Conway's Game of Life, using floating point values instead of integers
A continuous version of Conway's Life, using floating point values instead of integers: supports many interesting phenomena such as gliders that can travel in any direction, rotating pairs of gliders, wickstretchers and the appearance of elastic tension in the 'cords' that join the blobs. Slides showing how the rule…
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The software development final exam: Algorithms and Data Structures
If you would like me to grade your answers, please send an email to cperciva-exam-part1@tarsnap.com [EDIT: I have now finished marking part 1 answers; please do not send me any more] with your answers to the above questions along with the following two:
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Factorization diagrams in Haskell
Meta Title: Math, Sports Data & IPTV: A Portugal Guide Meta Description: Explore how math-minded sports fans use IPTV in Portugal to watch live football, Champi
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What is static program analysis?
The halting problem asks whether the execution of a specific program for a given input will terminate.
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Myths about Hash Tables
A hash table is data structure that is used to search for exact matches to a search key. For searching, they work like this: Take a search key (example: the word “cat”) Hash the search …
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A group of Finnish math teachers write an open textbook in a weekend hackathon
A group of Finnish mathematics researchers, teachers and students write an upper secondary mathematics textbook in a booksprint. The event s...
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Alligator Eggs
In 2007, I met Philip Wadler at a conference, who mentioned to me that he wanted to teach lambda calculus to his eight-year-old children.
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Did NSA Put a Secret Backdoor in New Encryption Standard? (2007)
Random numbers are critical for cryptography: for encryption keys, random authentication challenges, initialization vectors, nonces, key-agreement schemes, generating prime numbers and so on. Break the random-number generator, and most of the time you break the entire security system. Which is why you should worry…