Add the possibility to control the storage mode of scalar value (by value or reference) in order to avoid unecessary copies when using complex scalar types (e.g., a AutoDiffScalar)
Add the possibility to control the storage mode of scalar value (by value or reference)
in order to avoid unecessary copies when using complex scalar types (e.g., a AutoDiffScalar)

madlib/eigen,madlib/eigen,madlib/eigen,madlib/eigen