From 8aeb4667d7fdeacbbd767c21bdeb3a767a8261c3 Mon Sep 17 00:00:00 2001
From: Orange <orange-cpp@yandex.ru>
Date: Wed, 17 Sep 2025 17:30:57 +0300
Subject: [PATCH 1/3] decomposed mutiplication

---
 include/omath/linear_algebra/mat.hpp | 52 ++++++++++++++++++----------
 1 file changed, 33 insertions(+), 19 deletions(-)

diff --git a/include/omath/linear_algebra/mat.hpp b/include/omath/linear_algebra/mat.hpp
index 4f5a7ed0..2d255843 100644
--- a/include/omath/linear_algebra/mat.hpp
+++ b/include/omath/linear_algebra/mat.hpp
@@ -158,25 +158,10 @@ namespace omath
             Mat<Rows, OtherColumns, Type, StoreType> result;
 
             if constexpr (StoreType == MatStoreType::ROW_MAJOR)
-                for (std::size_t i = 0; i < Rows; ++i)
-                    for (std::size_t k = 0; k < Columns; ++k)
-                    {
-                        const Type aik = at(i, k);
-                        for (std::size_t j = 0; j < OtherColumns; ++j)
-                            result.at(i, j) += aik * other.at(k, j);
-                    }
-            else if constexpr (StoreType == MatStoreType::COLUMN_MAJOR)
-                for (std::size_t j = 0; j < OtherColumns; ++j)
-                    for (std::size_t k = 0; k < Columns; ++k)
-                    {
-                        const Type bkj = other.at(k, j);
-                        for (std::size_t i = 0; i < Rows; ++i)
-                            result.at(i, j) += at(i, k) * bkj;
-                    }
-            else
-                std::unreachable();
-
-            return result;
+                return cache_friendly_multiply_row_major(other);
+            if constexpr (StoreType == MatStoreType::COLUMN_MAJOR)
+                return cache_friendly_multiply_col_major(other);
+            std::unreachable();
         }
 
         constexpr Mat& operator*=(const Type& f) noexcept
@@ -378,6 +363,35 @@ namespace omath
 
     private:
         std::array<Type, Rows * Columns> m_data;
+
+        template<size_t OtherColumns> [[nodiscard]]
+        constexpr Mat<Rows, OtherColumns, Type, MatStoreType::ROW_MAJOR>
+        cache_friendly_multiply_row_major(const Mat<Columns, OtherColumns, Type, MatStoreType::ROW_MAJOR>& other) const
+        {
+            Mat<Rows, OtherColumns, Type, MatStoreType::ROW_MAJOR> result;
+            for (std::size_t i = 0; i < Rows; ++i)
+                for (std::size_t k = 0; k < Columns; ++k)
+                {
+                    const Type aik = at(i, k);
+                    for (std::size_t j = 0; j < OtherColumns; ++j)
+                        result.at(i, j) += aik * other.at(k, j);
+                }
+            return result;
+        }
+        template<size_t OtherColumns> [[nodiscard]]
+        constexpr Mat<Rows, OtherColumns, Type, MatStoreType::COLUMN_MAJOR> cache_friendly_multiply_col_major(
+                const Mat<Columns, OtherColumns, Type, MatStoreType::COLUMN_MAJOR>& other) const
+        {
+            Mat<Rows, OtherColumns, Type, MatStoreType::COLUMN_MAJOR> result;
+            for (std::size_t j = 0; j < OtherColumns; ++j)
+                for (std::size_t k = 0; k < Columns; ++k)
+                {
+                    const Type bkj = other.at(k, j);
+                    for (std::size_t i = 0; i < Rows; ++i)
+                        result.at(i, j) += at(i, k) * bkj;
+                }
+            return result;
+        }
     };
 
     template<class Type = float, MatStoreType St = MatStoreType::ROW_MAJOR> [[nodiscard]]

From 68ec42d9ed955f1a1a30bb8f59c135a0e145ebd2 Mon Sep 17 00:00:00 2001
From: Orange <orange-cpp@yandex.ru>
Date: Wed, 17 Sep 2025 17:33:05 +0300
Subject: [PATCH 2/3] added space

---
 include/omath/linear_algebra/mat.hpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/omath/linear_algebra/mat.hpp b/include/omath/linear_algebra/mat.hpp
index 2d255843..096345cf 100644
--- a/include/omath/linear_algebra/mat.hpp
+++ b/include/omath/linear_algebra/mat.hpp
@@ -378,6 +378,7 @@ namespace omath
                 }
             return result;
         }
+
         template<size_t OtherColumns> [[nodiscard]]
         constexpr Mat<Rows, OtherColumns, Type, MatStoreType::COLUMN_MAJOR> cache_friendly_multiply_col_major(
                 const Mat<Columns, OtherColumns, Type, MatStoreType::COLUMN_MAJOR>& other) const

From 874b028e8608a5cb28b2661282d5880b4f78e56b Mon Sep 17 00:00:00 2001
From: Orange <orange-cpp@yandex.ru>
Date: Wed, 17 Sep 2025 17:38:17 +0300
Subject: [PATCH 3/3] removed unused var

---
 include/omath/linear_algebra/mat.hpp | 2 --
 1 file changed, 2 deletions(-)

diff --git a/include/omath/linear_algebra/mat.hpp b/include/omath/linear_algebra/mat.hpp
index 096345cf..99f87757 100644
--- a/include/omath/linear_algebra/mat.hpp
+++ b/include/omath/linear_algebra/mat.hpp
@@ -155,8 +155,6 @@ namespace omath
         constexpr Mat<Rows, OtherColumns, Type, StoreType>
         operator*(const Mat<Columns, OtherColumns, Type, StoreType>& other) const
         {
-            Mat<Rows, OtherColumns, Type, StoreType> result;
-
             if constexpr (StoreType == MatStoreType::ROW_MAJOR)
                 return cache_friendly_multiply_row_major(other);
             if constexpr (StoreType == MatStoreType::COLUMN_MAJOR)