Activating and deactivating the API-active state is achieved through calls to place HR here
place HR here The above calls should be regarded as barriers: all nodes in the PLAPACK base communicator must make the call.
The API state of PLAPACK can be queried with the call place HR here
place HR here This will return
PLA_STATE_API_ACTIVE. While PLAPACK is in the API-active state, the calls described in this chapter can be used to access the contents of linear algebra objects.
We shall see in the next chapter that communication in PLAPACK is achieved through calls to the copy and reduce operations. Since these operations in turn call MPI, they may not be called while PLAPACK is API-active. In subsequent sections, global operations are given that themselves call the copy and reduce operations. These cannot be called while in API-active state either. In Appendix , we indicated whether a call is API-safe, meaning that the call can be made while PLAPACK is API-active. Failure to observe these restrictions can result in the contents of an object becoming inconsistent and/or an application deadlocking.