Fix a bunch of type checkings

src/algebra/DenseMatrix.hpp

@@ -35,13 +35,13 @@ class DenseMatrix   // LCOV_EXCL_LINE
     return m_nb_rows == m_nb_columns;
   }
 
-  friend DenseMatrix<std::remove_const_t<DataType>>
+  friend PUGS_INLINE DenseMatrix<std::remove_const_t<DataType>>
   copy(const DenseMatrix& A) noexcept
   {
     return {A.m_nb_rows, A.m_nb_columns, copy(A.m_values)};
   }
 
-  friend DenseMatrix<std::remove_const_t<DataType>>
+  friend PUGS_INLINE DenseMatrix<std::remove_const_t<DataType>>
   transpose(const DenseMatrix& A)
   {
     DenseMatrix<std::remove_const_t<DataType>> A_transpose{A.m_nb_columns, A.m_nb_rows};
@@ -53,7 +53,7 @@ class DenseMatrix   // LCOV_EXCL_LINE
     return A_transpose;
   }
 
-  friend DenseMatrix
+  friend PUGS_INLINE DenseMatrix
   operator*(const DataType& a, const DenseMatrix& A)
   {
     DenseMatrix<std::remove_const_t<DataType>> aA = copy(A);
@@ -61,14 +61,16 @@ class DenseMatrix   // LCOV_EXCL_LINE
   }
 
   template <typename DataType2>
-  PUGS_INLINE Vector<std::remove_const_t<DataType2>>
+  PUGS_INLINE Vector<std::remove_const_t<DataType>>
   operator*(const Vector<DataType2>& x) const
   {
+    static_assert(std::is_same_v<std::remove_const_t<DataType>, std::remove_const_t<DataType2>>,
+                  "incompatible data types");
     Assert(m_nb_columns == x.size());
     const DenseMatrix& A = *this;
-    Vector<std::remove_const_t<DataType2>> Ax{m_nb_rows};
+    Vector<std::remove_const_t<DataType>> Ax{m_nb_rows};
     for (size_t i = 0; i < m_nb_rows; ++i) {
-      DataType2 Axi = A(i, 0) * x[0];
+      std::remove_const_t<DataType> Axi = A(i, 0) * x[0];
       for (size_t j = 1; j < m_nb_columns; ++j) {
         Axi += A(i, j) * x[j];
       }
@@ -78,16 +80,18 @@ class DenseMatrix   // LCOV_EXCL_LINE
   }
 
   template <typename DataType2>
-  PUGS_INLINE DenseMatrix<std::remove_const_t<DataType2>>
+  PUGS_INLINE DenseMatrix<std::remove_const_t<DataType>>
   operator*(const DenseMatrix<DataType2>& B) const
   {
+    static_assert(std::is_same_v<std::remove_const_t<DataType>, std::remove_const_t<DataType2>>,
+                  "incompatible data types");
     Assert(m_nb_columns == B.numberOfRows());
     const DenseMatrix& A = *this;
     DenseMatrix<std::remove_const_t<DataType>> AB{m_nb_rows, B.numberOfColumns()};
 
     for (size_t i = 0; i < m_nb_rows; ++i) {
       for (size_t j = 0; j < B.numberOfColumns(); ++j) {
-        DataType2 ABij = 0;
+        std::remove_const_t<DataType> ABij = 0;
         for (size_t k = 0; k < m_nb_columns; ++k) {
           ABij += A(i, k) * B(k, j);
         }
@@ -118,6 +122,8 @@ class DenseMatrix   // LCOV_EXCL_LINE
   PUGS_INLINE DenseMatrix&
   operator-=(const DenseMatrix<DataType2>& B)
   {
+    static_assert(std::is_same_v<std::remove_const_t<DataType>, std::remove_const_t<DataType2>>,
+                  "incompatible data types");
     Assert(m_nb_rows == B.numberOfRows());
     Assert(m_nb_columns == B.numberOfColumns());
 
@@ -130,6 +136,8 @@ class DenseMatrix   // LCOV_EXCL_LINE
   PUGS_INLINE DenseMatrix&
   operator+=(const DenseMatrix<DataType2>& B)
   {
+    static_assert(std::is_same_v<std::remove_const_t<DataType>, std::remove_const_t<DataType2>>,
+                  "incompatible data types");
     Assert(m_nb_rows == B.numberOfRows());
     Assert(m_nb_columns == B.numberOfColumns());
 
@@ -142,6 +150,8 @@ class DenseMatrix   // LCOV_EXCL_LINE
   PUGS_INLINE DenseMatrix<std::remove_const_t<DataType>>
   operator+(const DenseMatrix<DataType2>& B) const
   {
+    static_assert(std::is_same_v<std::remove_const_t<DataType>, std::remove_const_t<DataType2>>,
+                  "incompatible data types");
     Assert(m_nb_rows == B.numberOfRows());
     Assert(m_nb_columns == B.numberOfColumns());
     DenseMatrix<std::remove_const_t<DataType>> sum{B.numberOfRows(), B.numberOfColumns()};
@@ -156,6 +166,8 @@ class DenseMatrix   // LCOV_EXCL_LINE
   PUGS_INLINE DenseMatrix<std::remove_const_t<DataType>>
   operator-(const DenseMatrix<DataType2>& B) const
   {
+    static_assert(std::is_same_v<std::remove_const_t<DataType>, std::remove_const_t<DataType2>>,
+                  "incompatible data types");
     Assert(m_nb_rows == B.numberOfRows());
     Assert(m_nb_columns == B.numberOfColumns());
     DenseMatrix<std::remove_const_t<DataType>> difference{B.numberOfRows(), B.numberOfColumns()};