Tpetra::Map should check for whether Kokkos is initialized (esp. if input Node is null)
Created by: mhoemmen
@trilinos/tpetra
This blocks #57.
Per #57, we plan to replace Node entirely. As a backwards compatibility measure, we would let the input Teuchos::RCP<Node>
instance be null, so that users could omit it. In fact, Tpetra::Map does not currently check whether the Node instance is null. Node instances currently initialize Kokkos if it is not already initialized. Thus, if we let the Node be null, it could be possible for Kokkos not to be initialized by the time we construct a Map.
Therefore, Tpetra::Map's constructors should check whether Kokkos has been initialized (in particular, whether device_type::execution_space has been initialized).