<?php
/**
* Example usage of the LW_Matrix class
*
* Will show a variety of methods and how to handle errors
* ©2012 Jon Lawrence
*/
require_once "matrix.class.php"; //require the LW_Matrix class
/**
* Creating a matrix via constructor
* | 1 2 3 |
* | 4 5 6 |
* | 7 8 9 |
*/
$myMatrix = new LW_Matrix("[1,2,3;4,5,6;7,8,9]");
//For the sake of ease in demonstration, everything will
//be 'preformatted' in html.
echo "<pre>\n";
//return if it's a square matrix. In this case, true.
$isSquare = $myMatrix->isSquare();
//use a try block to so you can catch if an operation fails
try {
//Get the inverse matrix
$invMatrix = $myMatrix->inverse();
} catch (Exception $e) {
$eCode = $e->getCode();
if($eCode==LW_MATRIX_E_NO_INVERSE) {
//Show your own error based on constant
echo "No inverse matrix exists\n";
//Show the error string provided by the class
echo $e->getMessage() ."\n";
}
}
//use the __toString() method by default for printing
echo "\$myMatrix : ". $myMatrix ."\n";
//Transpose the matrix, use (false, false) as parameters to return LW_Matrix object
$tranMatrix = $myMatrix->transpose(false, false);
echo "\$tranMatrix : ". $tranMatrix ."\n";
//Creating an identity matrix that is 3 by 3
$identMatrix = new LW_Matrix();
$identMatrix->createIdentity(3);
echo "\$identMatrix : ". $identMatrix ."\n";
/**
* Solving a set of linear equations using the LW_Matrix Class
*
* Use in a try block to avoid a fatal error, and possibly
* provide the user a reason why it failed
* Equations to use:
* 3x + 2y - z = 1
* 2x - 2y + 4z = -2
* -1x + .5y - z = 0
*
* Matrices will then be:
* | 3 2 -1 |
* A = | 2 -2 4 |
* | -1 .5 -1 |
* for the variable, the solution set will be:
* | 1 |
* C = | -2 |
* | 0 |
*
* Solving the set is defined by A^(-1)C, with the solution set
* being in the form of
* | x |
* solution = | y |
* | z |
*/
try {
$A = new LW_Matrix("[3,2,-1;2,-2,4;-1,.5,-1]");
$C = new LW_Matrix("[1;-2;0]");
//get the inverse of A
$invA = $A->inverse();
//now multiply the inverse by C
$solution = $invA->mpMatrix($C);
/**
* If we want to break down the solution to their own
* variables, do the following:
*/
//first, remove the brackets
$sText = str_replace("[", "", $solution->toString());
$sText = str_replace("]", "", $sText);
//Now explode the contents to their own variables:
list($x,$y,$z) = explode(";", $sText);
//output the variables
echo "x = $x\ny = $y\nz = $z";
} catch (Exception $e) {
//show the default string of the first thing to go wrong
echo "\n". $e->getMessage() ."\n";
}
/**
* Now that you are familiar with how the class is used,
* and have plenty of documentation to reference, go have fun!
*/
?>
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