what structrue do mpi have

MPI (Message Passing Interface) has a hierarchical structure consisting of the following components:

1. MPI Processes: These are the individual programs or tasks that run on different processors or nodes of a parallel computing system.

2. MPI Communicators: These are objects that define the communication context for a group of MPI processes. Communicators are used to specify the group of processes that participate in a communication operation.

3. MPI Message Buffers: These are the data structures used to hold data that is being transmitted between MPI processes.

4. MPI Datatypes: These are the data types used by MPI to describe the layout of data in message buffers.

5. MPI Operations: These are mathematical operations, such as addition or multiplication, that can be performed on data during a communication operation.

6. MPI Topologies: These are structures that define the physical or logical arrangement of MPI processes in a parallel computing system. Examples of MPI topologies include Cartesian grids, graphs, and trees.

7. MPI Collective Operations: These are operations that involve communication and computation among all the MPI processes in a communicator. Examples of MPI collective operations include scatter, gather, and reduce.