ExaTN:: Tensor Runtime: Tensor graph node executor REVISION: 2019/10/04

Copyright (C) 2018-2019 Dmitry Lyakh, Tiffany Mintz, Alex McCaskey Copyright (C) 2018-2019 Oak Ridge National Laboratory (UT-Battelle)

Rationale: (a) Tensor node executor provides actual implementation of registered tensor operations. Actual tensor operations are submitted for generally asynchronous execution via the .execute method overloads, which return an asynchronous execution handle assoicated with the submitted tensor operation. After submission, the completion status of the the tensor operation can be checked or enforced via the .sync method by providing the asynchronous execution handle previously returned by the .submit method.