Dynamic Programming is a discrete optimization technique. It means, the variables we want to calculate using this method are discrete. As an example, if x is one such variable then is acceptable, but ‘x is a real number between 0 and 1′ is NOT acceptable since there are infinitely many real numbers between 0 and 1. In math terms, we can say that the domain of the variable x is a countable set.
Problems that are solved by dynamic programming are recursive nature. Let’s look at the problem that ask us to calculate the sum up to a number, i.e., if is such a function then . The recursive definition (assuming i is non negative) is following:
Few years back, I wrote a simple logging library in ActionScript3 using the Chain of Responsibility pattern. Recently, I dug up the old codes, made some modifications, and put it in github for other people to use and contribute. In this post, I will mainly focus on how to use the library and do some project specific modifications, but I will also briefly discuss my reasons for using the Chain Of Responsibility and the Singleton Pattern. I started writing this library with the following 4 goals in mind:
- It should be easily accessible to all of the classes of a project.
- It should be able to write logging information to different output sources, i.e., file, database, console, etc., and additional output sources can be added easily.
- It should be able to handle different levels of logging like FATAL_ERROR or INFO (as different actions may be needed for handling different levels), and additional levels can be added easily.
- It should require minimal setup.