Add TinyMatrix's double-dot product

Also add a bunch of non discard qualifiers for TinyMatrix and TinyVector and forbids Frobenius norm for non floating point TinyMatrix

src/language/modules/MathModule.cpp

@@ -71,6 +71,18 @@ MathModule::MathModule()
                               return dot(x, y);
                             }));
 
+  this->_addBuiltinFunction("doubleDot", std::function([](const TinyMatrix<1> A, const TinyMatrix<1> B) -> double {
+                              return doubleDot(A, B);
+                            }));
+
+  this->_addBuiltinFunction("doubleDot", std::function([](const TinyMatrix<2> A, const TinyMatrix<2> B) -> double {
+                              return doubleDot(A, B);
+                            }));
+
+  this->_addBuiltinFunction("doubleDot", std::function([](const TinyMatrix<3>& A, const TinyMatrix<3>& B) -> double {
+                              return doubleDot(A, B);
+                            }));
+
   this->_addBuiltinFunction("tensorProduct",
                             std::function([](const TinyVector<1> x, const TinyVector<1> y) -> TinyMatrix<1> {
                               return tensorProduct(x, y);