Stoimen Popov05/09/12
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0 replies
Stoimen Popov is back with another episode in his Algorithm of the Week series, and this week he tackles prime numbers. Stoimen begins with a very basic (brute force) approach, and then refines his algorithm to be far more effective, though it still works best for smaller numbers.
Tony Russell-rose05/06/12
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0 replies
I need to compare two text classifiers – one human, one machine. They are assigning multiple tags from an ontology. We have an initial corpus of ~700 records tagged by both classifiers. The goal is to measure the ‘value added’ by the human. However, we don’t yet have any ground truth data (i.e. agreed annotations).
Stoimen Popov04/24/12
6863 views
3 replies
Do you know what day of the week was the day you were born? Monday or maybe Saturday? What about January 31st, 1883? Well, Stoimen Popov has created this post to explain a useful algorithm for determining what day of the week a certain date falls on.
Stoimen Popov04/17/12
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0 replies
Have you ever asked yourself which algorithm is used to find a word after clicking Ctrl+F and typing something? Well, you probably know the answer from the title, but in this article Stoimen Popov explains how exactly this is done.
Stoimen Popov04/11/12
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0 replies
Stoimen Popov returns with his Algorithm of the Week series, and in this post, he tackles the task of improving on the Brute Force String Matching and Rabin-Karp Sting Searching algorithms. To do this, he examines the flaws in the previous two, and explains how the Morris-Pratt String Searching algorithm can do better.
Stoimen Popov04/03/12
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0 replies
Last week, Stoimen Popov explained Brute Force String Matching, but cautioned that it is not the most efficient method for pattern matching. In this post, Stoimen breaks down a more efficient method, the Rabin-Karp Algorithm, and explains why it is more efficient in practice than in theory.
Stoimen Popov03/27/12
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0 replies
When it comes to string matching, the most basic approach is what is known as brute force, which simply means to check every single character from the text to match against the pattern. In this post, Stoimen Popov explains the principles behind Brute Force String Matching, demonstrates its implementation, and shows you what cases it is best used for.
Jose Asuncion03/25/12
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0 replies
This is a self imposed machine problem written for a lesson lesson on Frequent Itemsets and the Apriori Algorithm. The program that would find the top five frequent item sets among a set of baskets.
Stoimen Popov03/21/12
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0 replies
Radix sort is an elegant and fast integer-sorting algorithm as explained in the following cheatsheet. In this post, Stoimen has provided an Algorithm Cheatsheet to help you out!
Stoimen Popov03/20/12
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0 replies
Stoimen Popov continues his series on Algorithms, this week tackling Radix Sort. In this post, Stoimen explains the implementation of Radix Sort using PHP, and provides a Pros and Cons list to help you decide if Radix Sort is right for your situation.
Jose Asuncion03/18/12
3805 views
0 replies
The Apriori algorithm is a basic method for finding frequent itemsets. The latter is used to generate association rules with high confidence and high interest. Here is my summary of it along with a running example. The following set of baskets will be used:
Stoimen Popov03/13/12
5353 views
1 replies
In general Quicksort consists of some very simple steps. First we have to choose an element from the list (called a pivot) then we must put all the elements with a value less than the pivot on the left side of the pivot and all the items with value greater than the pivot on its right side. After that we must repeat these steps for the left and the right sub-lists. As Stoimen Popov explains, that is Quicksort! Simple and elegant!
John Cook03/11/12
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2 replies
In Peter Norvig’s talk 'The Unreasonable Effectiveness of Data', he changes Bayes’ theorem to make an example algorithm work better. He goes on to explain why reality is complicated and we've got to do the best we can...
Stoimen Popov01/31/12
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0 replies
I will show you how you can save space for certain implementations by reducing the amount of characters you are encoding using relative encoding.
Peter Karich01/29/12
2921 views
2 replies
Over the last two days I’ve read the old Java code of a board game. Although the game
still compiles and works (it even works on a Zaurus device) the code
itself is horrible: no unit tests, thread issues, a lot of static usages
and mixed...
