7.1 psb_init — Initializes PSBLAS parallel environment
call psb_init(ctxt, np, basectxt, ids)
This subroutine initializes the PSBLAS parallel environment, defining a virtual
- Number of processes in the PSBLAS virtual parallel machine.
Specified as: an integer value. Default: use all available processes.
- the initial communication context. The new context will be defined
from the processes participating in the initial one.
Specified as: an integer value. Default: use MPI_COMM_WORLD.
- Identities of the processes to use for the new context; the argument is
ignored when np is not specified. This allows the processes in the new
environment to be in an order different from the original one.
Specified as: an integer array. Default: use the indices (0…np - 1).
- the communication context identifying the virtual parallel machine, type
psb_ctxt_type. Note that this is always a duplicate of basectxt,
so that library communications are completely separated from other
Specified as: an integer variable.
- A call to this routine must precede any other PSBLAS call.
- It is an error to specify a value for np greater than the number of processes
available in the underlying base parallel environment.