diff --git a/Classes/PHPExcel/Calculation/MathTrig.php b/Classes/PHPExcel/Calculation/MathTrig.php
index f3ae111e..689d59ff 100644
--- a/Classes/PHPExcel/Calculation/MathTrig.php
+++ b/Classes/PHPExcel/Calculation/MathTrig.php
@@ -316,14 +316,17 @@ class PHPExcel_Calculation_MathTrig {
 		}
 
 		if ((is_numeric($number)) && (is_numeric($significance))) {
-            if (($number == 0.0 ) || ($significance == 0.0)) {
+            if ($significance == 0.0) {
+                return PHPExcel_Calculation_Functions::DIV0();
+            } elseif ($number == 0.0) {
 				return 0.0;
 			} elseif (self::SIGN($number) == self::SIGN($significance)) {
 				return floor($number / $significance) * $significance;
 			} else {
 				return PHPExcel_Calculation_Functions::NaN();
 			}
-		}
+		} else
+
 		return PHPExcel_Calculation_Functions::VALUE();
 	}	//	function FLOOR()
 
@@ -606,27 +609,27 @@ class PHPExcel_Calculation_MathTrig {
 		if (!is_array($matrixData1)) { $matrixData1 = array(array($matrixData1)); }
 		if (!is_array($matrixData2)) { $matrixData2 = array(array($matrixData2)); }
 
-		$rowA = 0;
-		foreach($matrixData1 as $matrixRow) {
-			if (!is_array($matrixRow)) { $matrixRow = array($matrixRow); }
-			$columnA = 0;
-			foreach($matrixRow as $matrixCell) {
-				if ((is_string($matrixCell)) || ($matrixCell === null)) {
-					return PHPExcel_Calculation_Functions::VALUE();
-				}
-				$matrixAData[$rowA][$columnA] = $matrixCell;
-				++$columnA;
-			}
-			++$rowA;
-		}
 		try {
+            $rowA = 0;
+            foreach($matrixData1 as $matrixRow) {
+                if (!is_array($matrixRow)) { $matrixRow = array($matrixRow); }
+                $columnA = 0;
+                foreach($matrixRow as $matrixCell) {
+                    if ((!is_numeric($matrixCell)) || ($matrixCell === null)) {
+                        return PHPExcel_Calculation_Functions::VALUE();
+                    }
+                    $matrixAData[$rowA][$columnA] = $matrixCell;
+                    ++$columnA;
+                }
+                ++$rowA;
+            }
 			$matrixA = new PHPExcel_Shared_JAMA_Matrix($matrixAData);
 			$rowB = 0;
 			foreach($matrixData2 as $matrixRow) {
 				if (!is_array($matrixRow)) { $matrixRow = array($matrixRow); }
 				$columnB = 0;
 				foreach($matrixRow as $matrixCell) {
-					if ((is_string($matrixCell)) || ($matrixCell === null)) {
+					if ((!is_numeric($matrixCell)) || ($matrixCell === null)) {
 						return PHPExcel_Calculation_Functions::VALUE();
 					}
 					$matrixBData[$rowB][$columnB] = $matrixCell;
@@ -636,12 +639,13 @@ class PHPExcel_Calculation_MathTrig {
 			}
 			$matrixB = new PHPExcel_Shared_JAMA_Matrix($matrixBData);
 
-			if (($rowA != $columnB) || ($rowB != $columnA)) {
+			if ($columnA != $rowB) {
 				return PHPExcel_Calculation_Functions::VALUE();
 			}
 
 			return $matrixA->times($matrixB)->getArray();
 		} catch (PHPExcel_Exception $ex) {
+            var_dump($ex->getMessage());
 			return PHPExcel_Calculation_Functions::VALUE();
 		}
 	}	//	function MMULT()
diff --git a/Classes/PHPExcel/Shared/JAMA/Matrix.php b/Classes/PHPExcel/Shared/JAMA/Matrix.php
index b893a447..1e7c334a 100644
--- a/Classes/PHPExcel/Shared/JAMA/Matrix.php
+++ b/Classes/PHPExcel/Shared/JAMA/Matrix.php
@@ -1028,7 +1028,7 @@ class PHPExcel_Shared_JAMA_Matrix {
 			$LU = new PHPExcel_Shared_JAMA_LUDecomposition($this);
 			return $LU->solve($B);
 		} else {
-			$QR = new QRDecomposition($this);
+			$QR = new PHPExcel_Shared_JAMA_QRDecomposition($this);
 			return $QR->solve($B);
 		}
 	}	//	function solve()
@@ -1054,6 +1054,4 @@ class PHPExcel_Shared_JAMA_Matrix {
 		$L = new PHPExcel_Shared_JAMA_LUDecomposition($this);
 		return $L->det();
 	}	//	function det()
-
-
 }	//	class PHPExcel_Shared_JAMA_Matrix
diff --git a/unitTests/Classes/PHPExcel/Calculation/DateTimeTest.php b/unitTests/Classes/PHPExcel/Calculation/DateTimeTest.php
index 57692a34..d4bdc5ab 100644
--- a/unitTests/Classes/PHPExcel/Calculation/DateTimeTest.php
+++ b/unitTests/Classes/PHPExcel/Calculation/DateTimeTest.php
@@ -13,6 +13,8 @@ class DateTimeTest extends PHPUnit_Framework_TestCase
             define('PHPEXCEL_ROOT', APPLICATION_PATH . '/');
         }
         require_once(PHPEXCEL_ROOT . 'PHPExcel/Autoloader.php');
+
+        PHPExcel_Calculation_Functions::setCompatibilityMode(PHPExcel_Calculation_Functions::COMPATIBILITY_EXCEL);
 	}
 
     /**
diff --git a/unitTests/Classes/PHPExcel/Calculation/EngineeringTest.php b/unitTests/Classes/PHPExcel/Calculation/EngineeringTest.php
index 647da09f..1f511ffa 100644
--- a/unitTests/Classes/PHPExcel/Calculation/EngineeringTest.php
+++ b/unitTests/Classes/PHPExcel/Calculation/EngineeringTest.php
@@ -17,6 +17,8 @@ class EngineeringTest extends PHPUnit_Framework_TestCase
             define('PHPEXCEL_ROOT', APPLICATION_PATH . '/');
         }
         require_once(PHPEXCEL_ROOT . 'PHPExcel/Autoloader.php');
+
+        PHPExcel_Calculation_Functions::setCompatibilityMode(PHPExcel_Calculation_Functions::COMPATIBILITY_EXCEL);
 	}
 
     /**
diff --git a/unitTests/Classes/PHPExcel/Calculation/FinancialTest.php b/unitTests/Classes/PHPExcel/Calculation/FinancialTest.php
index b27a6a7d..f5689c95 100644
--- a/unitTests/Classes/PHPExcel/Calculation/FinancialTest.php
+++ b/unitTests/Classes/PHPExcel/Calculation/FinancialTest.php
@@ -13,6 +13,8 @@ class FinancialTest extends PHPUnit_Framework_TestCase
             define('PHPEXCEL_ROOT', APPLICATION_PATH . '/');
         }
         require_once(PHPEXCEL_ROOT . 'PHPExcel/Autoloader.php');
+
+        PHPExcel_Calculation_Functions::setCompatibilityMode(PHPExcel_Calculation_Functions::COMPATIBILITY_EXCEL);
 	}
 
     /**
diff --git a/unitTests/Classes/PHPExcel/Calculation/FunctionsTest.php b/unitTests/Classes/PHPExcel/Calculation/FunctionsTest.php
index 5e6ef962..01333294 100644
--- a/unitTests/Classes/PHPExcel/Calculation/FunctionsTest.php
+++ b/unitTests/Classes/PHPExcel/Calculation/FunctionsTest.php
@@ -13,6 +13,8 @@ class FunctionsTest extends PHPUnit_Framework_TestCase
             define('PHPEXCEL_ROOT', APPLICATION_PATH . '/');
         }
         require_once(PHPEXCEL_ROOT . 'PHPExcel/Autoloader.php');
+
+        PHPExcel_Calculation_Functions::setCompatibilityMode(PHPExcel_Calculation_Functions::COMPATIBILITY_EXCEL);
 	}
 
 	public function testDUMMY()
diff --git a/unitTests/Classes/PHPExcel/Calculation/LogicalTest.php b/unitTests/Classes/PHPExcel/Calculation/LogicalTest.php
index 46749d12..cc8f8b33 100644
--- a/unitTests/Classes/PHPExcel/Calculation/LogicalTest.php
+++ b/unitTests/Classes/PHPExcel/Calculation/LogicalTest.php
@@ -13,6 +13,8 @@ class LogicalTest extends PHPUnit_Framework_TestCase
             define('PHPEXCEL_ROOT', APPLICATION_PATH . '/');
         }
         require_once(PHPEXCEL_ROOT . 'PHPExcel/Autoloader.php');
+
+        PHPExcel_Calculation_Functions::setCompatibilityMode(PHPExcel_Calculation_Functions::COMPATIBILITY_EXCEL);
 	}
 
 	public function testTRUE()
diff --git a/unitTests/Classes/PHPExcel/Calculation/LookupRefTest.php b/unitTests/Classes/PHPExcel/Calculation/LookupRefTest.php
index 454422a1..6450b082 100644
--- a/unitTests/Classes/PHPExcel/Calculation/LookupRefTest.php
+++ b/unitTests/Classes/PHPExcel/Calculation/LookupRefTest.php
@@ -13,6 +13,8 @@ class LookupRefTest extends PHPUnit_Framework_TestCase
             define('PHPEXCEL_ROOT', APPLICATION_PATH . '/');
         }
         require_once(PHPEXCEL_ROOT . 'PHPExcel/Autoloader.php');
+
+        PHPExcel_Calculation_Functions::setCompatibilityMode(PHPExcel_Calculation_Functions::COMPATIBILITY_EXCEL);
 	}
 
     /**
diff --git a/unitTests/Classes/PHPExcel/Calculation/MathTrigTest.php b/unitTests/Classes/PHPExcel/Calculation/MathTrigTest.php
index e3d8c9d9..0059ed08 100644
--- a/unitTests/Classes/PHPExcel/Calculation/MathTrigTest.php
+++ b/unitTests/Classes/PHPExcel/Calculation/MathTrigTest.php
@@ -13,6 +13,8 @@ class MathTrigTest extends PHPUnit_Framework_TestCase
             define('PHPEXCEL_ROOT', APPLICATION_PATH . '/');
         }
         require_once(PHPEXCEL_ROOT . 'PHPExcel/Autoloader.php');
+
+        PHPExcel_Calculation_Functions::setCompatibilityMode(PHPExcel_Calculation_Functions::COMPATIBILITY_EXCEL);
 	}
 
     /**
diff --git a/unitTests/Classes/PHPExcel/Calculation/TextDataTest.php b/unitTests/Classes/PHPExcel/Calculation/TextDataTest.php
index ea7882b6..4b1caf51 100644
--- a/unitTests/Classes/PHPExcel/Calculation/TextDataTest.php
+++ b/unitTests/Classes/PHPExcel/Calculation/TextDataTest.php
@@ -13,6 +13,8 @@ class TextDataTest extends PHPUnit_Framework_TestCase
             define('PHPEXCEL_ROOT', APPLICATION_PATH . '/');
         }
         require_once(PHPEXCEL_ROOT . 'PHPExcel/Autoloader.php');
+
+        PHPExcel_Calculation_Functions::setCompatibilityMode(PHPExcel_Calculation_Functions::COMPATIBILITY_EXCEL);
 	}
 
     /**
diff --git a/unitTests/Classes/PHPExcel/CalculationTest.php b/unitTests/Classes/PHPExcel/CalculationTest.php
index 1a510a02..1de827ca 100644
--- a/unitTests/Classes/PHPExcel/CalculationTest.php
+++ b/unitTests/Classes/PHPExcel/CalculationTest.php
@@ -11,6 +11,8 @@ class CalculationTest extends PHPUnit_Framework_TestCase
             define('PHPEXCEL_ROOT', APPLICATION_PATH . '/');
         }
         require_once(PHPEXCEL_ROOT . 'PHPExcel/Autoloader.php');
+
+        PHPExcel_Calculation_Functions::setCompatibilityMode(PHPExcel_Calculation_Functions::COMPATIBILITY_EXCEL);
     }
 
     /**
@@ -25,8 +27,6 @@ class CalculationTest extends PHPUnit_Framework_TestCase
         PHPExcel_Calculation_Functions::setCompatibilityMode(PHPExcel_Calculation_Functions::COMPATIBILITY_OPENOFFICE);
         $resultOpenOffice = \PHPExcel_Calculation::getInstance()->_calculateFormulaValue($formula);
         $this->assertEquals($expectedResultOpenOffice, $resultOpenOffice, 'should be OpenOffice compatible');
-
-        PHPExcel_Calculation_Functions::setCompatibilityMode(PHPExcel_Calculation_Functions::COMPATIBILITY_EXCEL);
     }
 
     public function providerBinaryComparisonOperation()
diff --git a/unitTests/rawTestData/Calculation/MathTrig/MINVERSE.data b/unitTests/rawTestData/Calculation/MathTrig/MINVERSE.data
index 47586b22..40ee4284 100644
--- a/unitTests/rawTestData/Calculation/MathTrig/MINVERSE.data
+++ b/unitTests/rawTestData/Calculation/MathTrig/MINVERSE.data
@@ -1,4 +1,4 @@
-{1|2|3;4|5|6;7|8|9},			{-4.50359962737050E+15|9.00719925474099E+15|-4.50359962737050E+15;9.00719925474100E+15|-1.80143985094820E+16|9.00719925474099E+15;-4.50359962737050E+15|9.00719925474099E+15|-4.50359962737050E+15}
+{1|2|3;4|5|6;7|8|9},    {-4.50359962737050E+15|9.00719925474099E+15|-4.50359962737050E+15;9.00719925474100E+15|-1.80143985094820E+16|9.00719925474099E+15;-4.50359962737050E+15|9.00719925474099E+15|-4.50359962737050E+15}
 {10|20|30;40|50|60;70|80|90},		{7.03687441776639E+13|-1.40737488355328E+14|7.03687441776640E+13;-1.40737488355328E+14|2.81474976710656E+14|-1.40737488355328E+14;7.03687441776641E+13|-1.40737488355328E+14|7.03687441776640E+13}
 {8|1|6;3|5|7;4|9|2},			{1.47222222222222E-01|-1.44444444444444E-01|6.38888888888889E-02;-6.11111111111111E-02|2.22222222222222E-02|1.05555555555556E-01;-1.94444444444444E-02|1.88888888888889E-01|-1.02777777777778E-01}
 {4|-1;2|0},				{0|0.5;-1|2}
@@ -8,3 +8,8 @@
 {0.2|1|-0.9;0.35|10.8|4;-3.15|5},	"#VALUE!"
 {1|2;3|4},				{-2|1;1.5|-0.5}
 {1|2|1;3|4|2;1|1|2},			{-2|1|0;1.33333333333333|-0.33333333333333|-0.33333333333333;0.33333333333333|-0.33333333333333|0.66666666666667}
+{2|3;4|5},   {-2.5|1.5;2|-1}
+{5|8;7|9},  {-0.818181818181818|0.727272727272727;0.636363636363636|-0.454545454545455}
+{45|78;17|50},  {0.054112554112554|-0.084415584415584;-0.018398268398268|0.048701298701299}
+{2|2;2|1},   {-0.5|1.0;1|-1}
+{1|4|6;7|4|10;15|16|20},    {-0.2941176470588230|0.0588235294117647|0.0588235294117647;0.0367647058823529|-0.2573529411764710|0.1176470588235290;0.1911764705882350|0.1617647058823530|-0.0882352941176471}
\ No newline at end of file
diff --git a/unitTests/rawTestData/Calculation/MathTrig/MMULT.data b/unitTests/rawTestData/Calculation/MathTrig/MMULT.data
index 430dd88d..06af83a0 100644
--- a/unitTests/rawTestData/Calculation/MathTrig/MMULT.data
+++ b/unitTests/rawTestData/Calculation/MathTrig/MMULT.data
@@ -1,11 +1,12 @@
 {1|2;3|4},		{1|2;3|4},		{7|10;15|22}
 {1|2|3;4|5|6;7|8|9},	{1|2|3;4|5|6;7|8|9},	{30|36|42;66|81|96;102|126|150}
-{1|2;3|4},		2,			{2|4;6|8}
-{1|2;3|4},		{2},			{2|4;6|8}
-2,			{1|2;3|4},		{2|4;6|8}
-{2},			{1|2;3|4},		{2|4;6|8}
-{1|2;3|4},		{2|4},			{2|4;6|8}
-{1|2;3|4},		{2;4},			{2|4;6|8}
-{2|4},			{1|2;3|4},		{2|4;6|8}
-{2;4},			{1|2;3|4},		{2|4;6|8}
-{1|2;3|4;5|6},		{1|2|3;4|5|6},		{1|2|3;4|5|6;7|8|9}
+{1|2;3|4},		2,			"#VALUE!"   // Mismatched dimensions
+{1|2;3|4},		{2},			"#VALUE!"   // Mismatched dimensions
+{1.2;2.4},      {3.6|4.5},          {14.43|14.43;14.43|14.43}
+2,			{1|2;3|4},		"#VALUE!"   // Mismatched dimensions
+{2},			{1|2;3|4},		"#VALUE!"   // Mismatched dimensions
+{1|2;3|4},		{2|4},			"#VALUE!"
+{1|2;3|4},		{2;4},			{{10};{22}}
+{2|4},			{1|2;3|4},		{14|20}
+{2;4},			{1|2;3|4},		"#VALUE!"   // Mismatched dimensions
+{1|2;3|4;5|6},		{1|2|3;4|5|6},		{9|12|15;19|26|33;29|40|51}