Implement Circle header, rename all files to use .hpp extension.

include/J3ML/LinearAlgebra/Matrix.hpp

@@ -0,0 +1,66 @@
+#pragma once
+
+#include <cstddef>
+#include <cstdlib>
+#include <algorithm>
+#include "Vector.hpp"
+
+namespace J3ML::LinearAlgebra
+{
+
+
+    template <uint ROWS, uint COLS, typename T>
+    class Matrix
+    {
+        static constexpr uint Diag = std::min(ROWS, COLS);
+
+        using RowVector = Vector<ROWS, T>;
+        using ColVector = Vector<COLS, T>;
+        using DiagVector = Vector<Diag, T>;
+
+        enum { Rows = ROWS };
+        enum { Cols = COLS };
+
+        void AssertRowSize(uint rows)
+        {
+            assert(rows < Rows && "");
+        }
+        void AssertColumnSize(uint cols)
+        {
+            assert(cols < Cols && "");
+        }
+
+        RowVector GetRow(uint index) const;
+        ColVector GetColumn(uint index) const;
+        void SetRow(uint index, RowVector);
+        void SetColumn(uint index, ColVector);
+
+        RowVector &Row(uint index) const;
+        ColVector &Column(uint index) const;
+
+        const T At(uint row, uint col) const
+        {
+            AssertRowSize(row);
+            AssertColumnSize(col);
+
+            return elems[row][col];
+        }
+
+        T &At(uint row, uint col)
+        {
+            AssertRowSize(row);
+            AssertColumnSize(col);
+
+            return elems[row][col];
+        }
+
+        float* ptr();
+        const float* ptr() const;
+
+        float operator[](uint index) const;
+        float& operator[](uint index);
+
+    private:
+        T elems[ROWS][COLS];
+    };
+}