Bring in a row major version of Amit's matrix.

amt/matrix.hpp

@@ -1,4 +1,5 @@
-#pragma once
+#ifndef AMT_MATRIX_HPP
+#define AMT_MATRIX_HPP
 
 #include <cassert>
 #include <cstddef>
@@ -119,28 +120,28 @@ namespace amt {
 		constexpr const_reverse_iterator rbegin() const noexcept { return std::reverse_iterator(end()); }
 		constexpr const_reverse_iterator rend() const noexcept { return std::reverse_iterator(begin()); }
 
-		constexpr auto operator()(size_type r, size_type c) noexcept -> reference {
-			auto const index = r * m_col + c; // column-major;
+			constexpr auto operator()(size_type r, size_type c) noexcept -> reference {
+			auto const index = r + c * m_row; // row-major;
 			assert(index < size() && "Out of bound access");
 			return m_data[index];
 		}
 
 		constexpr auto operator()(size_type r, size_type c) const noexcept -> const_reference {
-			auto const index = r * m_col + c; // column-major;
+			auto const index = r + c * m_row; // row-major;
 			assert(index < size() && "Out of bound access");
 			return m_data[index];
 		}
 
-		constexpr auto operator[](size_type r) noexcept -> View<false> {
-			auto const base = r * m_col;
-			assert(r < rows() && "Out of bound access");
-			return { .data = m_data + base, .size = m_col };
+		constexpr auto operator[](size_type c) noexcept -> View<false> {
+			auto const base = c * m_row;
+			assert(c < cols() && "Out of bound access");
+			return { .data = m_data + base, .size = m_row };
 		}
 
-		constexpr auto operator[](size_type r) const noexcept -> View<true> {
-			auto const base = r * m_col;
-			assert(r < rows() && "Out of bound access");
-			return { .data = m_data + base, .size = m_col };
+		constexpr auto operator[](size_type c) const noexcept -> View<true> {
+			auto const base = c * m_row;
+			assert(c < cols() && "Out of bound access");
+			return { .data = m_data + base, .size = m_row };
 		}
 
 		friend void swap(Matrix& lhs, Matrix& rhs) noexcept {
@@ -158,7 +159,7 @@ namespace amt {
 
 } // namespace amt
 
-#if 0
+
 #include <format>
 namespace std {
 	template <typename T>
@@ -181,4 +182,5 @@ namespace std {
 	};
 
 } // namespace std
-#endif
+
+#endif // AMT_MATRIX_HPP