Archive for the ‘PHP’ Category

hi everyone, i am facing some problems concerned with how work flows , which step after which in my first codeigniter project .. it aims to be something like digg.com but smaller and just for getting my feet wet not for any commercial goals !

I used Jquery and the form validation class for making validation for the reregistration and logging in system , this is a screen shot .

Now anyone wanna read what i wrote , just download !

i am trying to complete it .. ISA

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It’s my first post about what i study in ┬ámy college , it is about solving a system of equations using the two famous numerical methods of Jacobi and Gauss .

This post is not about these numerical methods themselves but it is about their PHP implementation .

This is the code for Jacobi :

<?php
	$x = array(
		array(0,-(1/3),-(1/3),-(8/3)),
		array((1/3),0,-(1/3),(8/3)),
		array(-(1/3),(1/3),0,-(8/3))
	);
	$s = array(
		0,0,0
	);
	echo "<table border='1' style= 'width :90%'><tr>";
	echo "<td> k = 0</td><td> 0</td><td> 0</td><td> 0</td></tr>";
	for($i=1;$i<=30;$i++){
		echo "<tr>";
		$s0 = ( $s[0]*$x[0][0]) + ( $s[1]*$x[0][1])+($s[2]*$x[0][2]+$x[0][3]);
		$s1 = ($s[0]*$x[1][0]) + ($s[1]*$x[1][1]) + ($s[2]*$x[1][2]+$x[1][3]);
		$s2 = ( $s[0]*$x[2][0]) + ($s[1]*$x[2][1]) + ($s[2]*$x[2][2]+$x[2][3]);
		$s[0] = $s0;
		$s[1] = $s1;
		$s[2] = $s2;
		echo "<td> k = $i</td><td>".$s[0]."</td><td>".$s[1]."</td><td>".$s[2]."</td></tr>";
		//echo $i." :: ".$s[0]." :: ".$s[1]." :: ".$s[2]."<br>";
	}
	echo "</table>";
?>

And this is the gauss-siedle

	$x = array(
		array(0,0.2,-0.6,-0.4),
		array(-0.2,0,0.4,2),
		array(-0.2,0.4,0,0.6)
	);
	$s = array(
		0,0,0
	);
echo "0 :: 0 :: 0 :: 0<br>";
	for($i=1;$i<100;$i++){

		$s[0] =  $s[0]*$x[0][0] + $s[1]*$x[0][1] + $s[2]*$x[0][2]+$x[0][3];
		$s[1] = $s[0]*$x[1][0] + $s[1]*$x[1][1] + $s[2]*$x[1][2]+$x[1][3];
		$s[2] = $s[0]*$x[2][0] + $s[1]*$x[2][1] + $s[2]*$x[2][2]+$x[2][3];

		echo $i." :: ".$s[0]." :: ".$s[1]." :: ".$s[2]."<br>";
	}
?>

How to use it ?

just put the X coefficients into the $x array after putting it in the valid form !

If you have a problem with approximation accuracy use the round() function