From 2c5c00f88bcae5f5543d73c18b3f6e4d3dc8aa64 Mon Sep 17 00:00:00 2001
From: Jeff Moser <jeff@moserware.com>
Date: Wed, 1 Sep 2010 22:17:00 -0400
Subject: [PATCH] Added equals test and fixed some bugs

---
 PHPSkills/Numerics/Matrix.php     | 58 +++++++++++++++++++++++++++----
 UnitTests/Numerics/MatrixTest.php | 43 +++++++++++++++++++++--
 2 files changed, 92 insertions(+), 9 deletions(-)

diff --git a/PHPSkills/Numerics/Matrix.php b/PHPSkills/Numerics/Matrix.php
index e3f5ccf..568f867 100644
--- a/PHPSkills/Numerics/Matrix.php
+++ b/PHPSkills/Numerics/Matrix.php
@@ -16,6 +16,24 @@ class Matrix
         $this->_matrixRowData = $matrixData;
     }
 
+    public static function fromRowsColumns()
+    {
+        $args = \func_get_args();
+        $rows = $args[0];
+        $cols = $args[1];
+        $result = new Matrix($rows, $cols);
+        $currentIndex = 2;
+
+        for($currentRow = 0; $currentRow < $rows; $currentRow++)
+        {
+            for($currentCol = 0; $currentCol < $cols; $currentCol++)
+            {
+                $result->setValue($currentRow, $currentCol, $args[$currentIndex++]);
+            }
+        }
+
+        return $result;
+    }
 
     public function getRowCount()
     {
@@ -46,9 +64,6 @@ class Matrix
              $currentRowTransposeMatrix < $this->_columnCount;
              $currentRowTransposeMatrix++)
         {
-            $transposeMatrixCurrentRowColumnValues = array();
-            $transposeMatrix[] = $transposeMatrixCurrentRowColumnValues;
-
             for ($currentColumnTransposeMatrix = 0;
                  $currentColumnTransposeMatrix < $this->_rowCount;
                  $currentColumnTransposeMatrix++)
@@ -58,7 +73,7 @@ class Matrix
             }
         }
 
-        return new Matrix($transposeMatrix);
+        return new Matrix($this->_columnCount, $this->_rowCount, $transposeMatrix);
     }
 
     private function isSquare()
@@ -152,7 +167,7 @@ class Matrix
             }
         }
 
-        return new Matrix($result);
+        return new Matrix($this->_columnCount, $this->_rowCount, $result);
     }
 
     public function getInverse()
@@ -288,7 +303,7 @@ class Matrix
         return new Matrix($this->_rowCount - 1, $this->_columnCount - 1, $result);
     }
 
-    private function getCofactor($rowToRemove, $columnToRemove)
+    public function getCofactor($rowToRemove, $columnToRemove)
     {
         // See http://en.wikipedia.org/wiki/Cofactor_(linear_algebra) for details
         // REVIEW: should things be reversed since I'm 0 indexed?
@@ -304,6 +319,37 @@ class Matrix
             return -1.0*$this->getMinorMatrix($rowToRemove, $columnToRemove)->getDeterminant();
         }
     }
+
+    public function equals($otherMatrix)
+    {
+        // If one is null, but not both, return false.
+        if ($otherMatrix == null)
+        {
+            return false;
+        }
+
+        if (($this->_rowCount != $otherMatrix->getRowCount()) || ($this->_columnCount != $otherMatrix->getColumnCount()))
+        {
+            return false;
+        }
+
+        for ($currentRow = 0; $currentRow < $this->_rowCount; $currentRow++)
+        {
+            for ($currentColumn = 0; $currentColumn < $this->_columnCount; $currentColumn++)
+            {
+                $delta =
+                    abs($this->_matrixRowData[$currentRow][$currentColumn] -
+                        $otherMatrix->getValue($currentRow, $currentColumn));
+
+                if ($delta > self::ERROR_TOLERANCE)
+                {
+                    return false;
+                }
+            }
+        }
+
+        return true;
+    }
 }
 
 class Vector extends Matrix
diff --git a/UnitTests/Numerics/MatrixTest.php b/UnitTests/Numerics/MatrixTest.php
index 19ee9c8..c351d39 100644
--- a/UnitTests/Numerics/MatrixTest.php
+++ b/UnitTests/Numerics/MatrixTest.php
@@ -5,6 +5,7 @@ require_once 'PHPUnit/TextUI/TestRunner.php';
 require_once(dirname(__FILE__) . '/../../PHPSkills/Numerics/Matrix.php');
 
 use \PHPUnit_Framework_TestCase;
+use Moserware\Numerics\Matrix;
 use Moserware\Numerics\SquareMatrix;
 
 class MatrixTest extends PHPUnit_Framework_TestCase
@@ -90,12 +91,48 @@ class MatrixTest extends PHPUnit_Framework_TestCase
         // Verified against http://www.wolframalpha.com/input/?i=det+%7B%7B3%2C1%2C4%2C1%2C5%2C9%2C2%2C6%7D%2C%7B5%2C3%2C5%2C8%2C9%2C7%2C9%2C3%7D%2C%7B2%2C3%2C8%2C4%2C6%2C2%2C6%2C4%7D%2C%7B3%2C3%2C8%2C3%2C2%2C7%2C9%2C5%7D%2C%7B0%2C2%2C8%2C8%2C4%2C1%2C9%2C7%7D%2C%7B1%2C6%2C9%2C3%2C9%2C9%2C3%2C7%7D%2C%7B5%2C1%2C0%2C5%2C8%2C2%2C0%2C9%7D%2C%7B7%2C4%2C9%2C4%2C4%2C5%2C9%2C2%7D%7D
         $this->assertEquals(1378143, $pi->getDeterminant());
     }
+
+    public function testEquals()
+    {
+        $a = new SquareMatrix(1, 2,
+                              3, 4);
+
+        $b = new SquareMatrix(1, 2,
+                              3, 4);
+
+        $this->assertTrue($a->equals($b));
+
+        $c = Matrix::fromRowsColumns(2, 3,
+                                     1, 2, 3,
+                                     4, 5, 6);
+
+        $d = Matrix::fromRowsColumns(2, 3,
+                                     1, 2, 3,
+                                     4, 5, 6);
+
+        $this->assertTrue($c->equals($d));
+
+        $e = Matrix::fromRowsColumns(3, 2,
+                                     1, 4,
+                                     2, 5,
+                                     3, 6);
+
+        $f = $e->getTranspose();
+        $this->assertTrue($d->equals($f));
+
+        // Test rounding (thanks to nsp on GitHub for finding this case)
+        $g = new SquareMatrix(1, 2.00000000000001,
+                              3, 4);
+
+        $h = new SquareMatrix(1, 2,
+                              3, 4);
+
+        $this->assertTrue($g->equals($h));
+    }
 }
 
 $testSuite = new \PHPUnit_Framework_TestSuite();
-$testSuite->addTest( new MatrixTest("testFourByFourDeterminant"));
-$testSuite->addTest( new MatrixTest("testEightByEightDeterminant"));
-
+$testSuite->addTest( new MatrixTest("testEquals"));
 \PHPUnit_TextUI_TestRunner::run($testSuite);
 
 ?>