#algorithms

I've always liked the look of contour lines and at one point I wondered how I could extract them from a simplex noise.

I've always liked the look of contour lines and at one point I wondered how I could extract them from a simplex noise.

Parallel versions of the map function are provided by two libraries: multiprocessing, and also its little known, but equally fantastic step child: multiprocessing.dummy.

This page gives a grid of intersection routines for various popular objects, pointing to resources in books and on the web.

"Frecency is a score given to each unique URI in Places, encompassing bookmarks, history and tags. This score is determined by the amount of revisitation, the type of those visits, how recent they were, and whether the URI was bookmarked or tagged. "

"Spatial indexing is increasingly important as more and more data and applications are geospatially-enabled. Efficiently querying geospatial data, however, is a considerable challenge: because the data is two-dimensional (or sometimes, more), you can't use standard indexing techniques to query on position. Spatial indexes solve this through a variety of techniques. In this post, we'll cover several - quadtrees, geohashes (not to be confused with geohashing), and space-filling curves - and reveal how they're all interrelated."

Surprised the code is so short. "Lately, I've been looking for ways to detect faces in photos with PHP. Nowadays, face detection is built in many consumer products (camera obviously, but also Google and iPhoto), and seems to be a pretty common job. So I expected to find many solutions for doing it with PHP. Surprisingly, the only one I could find is OpenCV, an opensource lib that was originally developed by Intel. OpenCV seems to perform well but you need to be able to install it on your server. In my case, I wanted to have a pure PHP solution, so it can work with most hosts."

"I hope you're convinced, by now, that programming languages with first-class functions let you find more opportunities for abstraction, which means your code is smaller, tighter, more reusable, and more scalable."

Almost kind of creep - an image resize algorithm that calculates least-important seams in an image to remove as it's resized / scaled.

"From Dattebayo's fansub release of Pythagoras Switch. I'm trying to hype up this dance so people will perform it in cosplay skits."

"MapReduce is a programming model and an associated implementation for processing and generating large data sets."