2.1 Initializing PLAPACK

   

Much like MPI provides the MPI_Init call to initialize the environment and MPI_Finalize to exit, the PLAPACK infrastructure is initialized by calling

Here the parameter comm equals an MPI communicator with a two dimensional topology. This communicator becomes the     base communicator for all communication in PLAPACK. By passing in MPI_COMM_NULL as the base communicator, one can allow the underlying system to generate an appropriate   communicator with   two-dimensional topology from MPI_COMM_WORLD.

Not surprisingly, PLAPACK is exited by calling

Since an application may wish to use a number of packages, each of which themselves may use PLAPACK, we provide an inquiry routine to check if PLAPACK has already been initialized:

Return value initialized equals FALSE(= 0) if PLAPACK is not yet initialized and TRUE( ) if it is.

One may wish to inquire the PLAPACK environment for the communicator used during initialization. For this we provide the routine

We provide two utility routines for a communicator with a two-dimensional topology from a communicator with a one-dimensional topology:

Notice that the ratio given in ratio need not be attainable: it is only a suggestion.