Implement GetRow, GetColumn, At methods for Mat2x2

include/J3ML/LinearAlgebra/Matrix2x2.h

@@ -6,12 +6,19 @@
 namespace LinearAlgebra {
     class Matrix2x2 {
     public:
+        enum { Rows = 3 };
+        enum { Cols = 3 };
         static const Matrix2x2 Zero;
         static const Matrix2x2 Identity;
         static const Matrix2x2 NaN;
 
-        Vector2 GetRow() const;
+        Vector2 GetRow(int index) const;
-        Vector2 GetColumn() const;
+        Vector2 GetColumn(int index) const;
+        float At(int x, int y) const;
+
+
+        Vector2 operator * (const Vector2& rhs) const;
+        Matrix2x2 operator * (const Matrix2x2 &rhs) const;
 
     protected:
         float elems[2][2];

src/J3ML/LinearAlgebra/Matrix2x2.cpp

@@ -2,4 +2,20 @@
 
 namespace LinearAlgebra {
 
+    Vector2 Matrix2x2::GetRow(int index) const {
+        float x = this->elems[index][0];
+        float y = this->elems[index][1];
+
+        return {x, y};
+    }
+
+    Vector2 Matrix2x2::GetColumn(int index) const {
+        float x = this->elems[0][index];
+        float y = this->elems[1][index];
+        return {x, y};
+    }
+
+    float Matrix2x2::At(int x, int y) const {
+        return this->elems[x][y];
+    }
 }