David Tavarez’s Home at davidtavarez.com

Google Wave… the new product of Google.

// May 30th, 2009 // No Comments » // General

Google Wave was presented at the Google I/O. This product appears to have the clear objective of becoming the new standard for people to interact online.

It is difficult to define what actually, so I left the video.

Playing with GTK# and Mono

// April 23rd, 2009 // No Comments » // General

After few days thinking and doing some research I decided to try C#. My first Project will be create a Translation widget using the Google's Translation API.

In few minutes I had this:

gTranslator 0.0.1

“Longer Common SubString Problem” PHP Implementation

// April 17th, 2009 // 1 Comment » // PHP

The longest common substring problem is to find the longest string (or strings) that is a substring (or are substrings) of two or more strings.

The problem of longest common subsequence arises whenever we search for similarities across multiple texts. A particularly important application is in finding a consensus among DNA sequences. The genes for building particular proteins evolve with time, but the functional regions must remain consistent in order to work correctly. By finding the longest common subsequence of the same gene in different species, we learn what has been conserved over time.

The longest common substring problem is a special case of edit distance, when substitutions are forbidden and only exact character match, insert, and delete are allowable edit operations. Under these conditions, the edit distance between p and t is n+m-2 |lcs(p,t)|, since we can delete the missing characters from p to the lcs(p,t) and insert the missing characters from $t$ to transform p to t. This is particularly interesting because the longest common subsequence can be faster to compute than edit distance.

For More Information about it, just google it!.

The Implementation.

/**
 * Implementación de el Algoritmo "Longer Common SubString" en dos (2) Cadenas dadas.
 *
 * @param string $a
 * @param string $b
 * @return integer
 */
function lcs($a, $b) {
	if (! is_string ( $a ) || ! is_string ( $b ))
		return false;
	$m = strlen ( $a );
	$n = strlen ( $b );
	for($i = 0; $i < $m; $i ++)
		$c [$i] [0] = 0;
	for($j = 0; $j < $n; $j ++)
		$c [0] [$j] = 0;
	for($i = 1; $i <= $m; $i ++) {
		for($j = 1; $j <= $n; $j ++) {
			if ($a [$i] == $b [$j])
				$c [$i] [$j] = $c [$i] [$j - 1] + 1;
			else {
				if ($c [$i - 1] [$j] >= $c [$i] [$j - 1])
					$c [$i] [$j] = $c [$i - 1] [$j];
				else
					$c [$i] [$j] = $c [$i] [$j - 1];
			}
		}
	}
	return $c [$m] [$n];
}

Google Chrome Japan

// February 28th, 2009 // 2 Comments » // General

Very Cool Video!

Glade 3 (3.4.1) Installer for Windows

// February 8th, 2009 // 4 Comments » // PHP-GTK

Well, after few hours around internet and testing all... finally I got Glade 3 Running!! very well! Actually I'm using it to create an php-gtk application.

This is how its looks:

Glade 3 running on Windows XP

And this is the application running:

GUI created using Glade 3

To download go to the winGlade section here: winGlade.