A new lighter implementation of K-means

See my old posting K-means in C++ .
Here you have a lightweight code

Stocastic Gradient Descent

Added a stocastic gradient descent to the linear regression code

Learning linear regression with gradient descend

Last week I restarted an old and good behavior (see A collection of algos and data structures published here). Every day, I take an well known algorithm and code it in boost and C++. Nothing else, just pure training and geeky fun. The only constrain is the time limit of 45mins, after a running session in St. James park.

Here you have the code for linear regression with gradient descent in C++, boost, and ublas.  Linear regression is an approach to modeling the relationship between a scalar dependent variable y and one or more explanatory variables denoted X. Ublas is a powerful set of c routines for efficient matrix and vector computations, Boost:: numeric provides an elegant C++ way of using ublas based on templates.

Here you have the code

Scaling requests with MemCached

A nice paper from Facebook about the use of memcached for scaling requests. Classical UDP connection-less techniques, are mixed with TCP coalescing via mcrouter. Also, they implement flow control, new mechanism for cache miss, and excess of requests on a particular key. The concept of pool is quite interesting.

Implement a binary search

with minimum number of comparisons

Browser war revisited

Find largest sum in a subarray

Given an array that may contain both positive and negative integers, find the sum of contiguous subarray of numbers which has the largest sum.

Hint: there is a divide & conquer solution in O(nlogn) and one cool solution in O(n)