Tuesday, 6 September 2011

A PHP Tutorial

PHP is an excellent server-side technology for dynamic webpage generation. Within a span of few years, it has gained immense popularity among developers. This excellent 5-Part tutorial written by Luigi Arlotta explains the basics of PHP programming. His style is so simple that even absolute beginners would have no trouble following this tutorial.

This tutorial is targeted at those users who may have never programmed using any language before. Also programmers who have experience in other languages can quickly browse through this series and get their PHP code running within minutes...


Tuesday, 30 August 2011


In Robocode, you deplete your opponent's energy and increase your own energy by hitting other bots with bullets. Thus, coming up with targeting algorithms to hit your opponents accurately is a cornerstone of a successful Robocode bot. Different algorithms are more appropriate for different Code Size divisions and styles of play.
The main components of a targeting system are:
  • Choosing a target (Melee only)
  • Energy Management - Whether or not to fire, what bullet power to use
  • Choosing a firing angle
Most descriptions of Robocode targeting systems focus on choosing a firing angle. For a learning gun, this is essentially a classification problem. The enemy robot can't react to where you fired your bullets because he can't see your gun or your bullets (until they hit). He can, however, see when you fire by monitoring your energy.
Some aspects that make Robocode targeting an interesting classification problem are:
  • You have a very small amount of time per tick to make a decision. Dropping in the most sophisticated classification algorithm you can find in a textbook won't work. This time needs to be split between inputting data and generating output values.
  • You have to continually make decisions - when you have no data, when you have 50 ticks, 500 ticks, or 20,000 ticks of data. Your algorithm has to perform well and remain fast enough throughout the entire battle.