generalized gradient
add field in Data_Function for vector-valued basis functions: generalized gradient
generalize Cal_Galerkin, Get_FunctionValue, etc. so that they accept the tensor values retuned by the generalized gradient
add field in Data_Function for vector-valued basis functions: generalized gradient
generalize Cal_Galerkin, Get_FunctionValue, etc. so that they accept the tensor values retuned by the generalized gradient