## psb_exit -- Exit from PSBLAS parallel environment

    call psb_exit(icontxt)
    call psb_exit(icontxt,close)

This subroutine exits from the PSBLAS parallel virtual machine.

Type:
  Synchronous.
On Entry
icontxt
  the communication context identifying the virtual parallel machine.
  Scope: global.
  Type: required.
  Intent: in.
  Specified as: an integer variable.
close
  Whether to close all data structures related to the virtual parallel machine, besides those associated with icontxt.
  Scope: global.
  Type: optional.
  Intent: in.
  Specified as: a logical variable, default value: true.

Notes

1. This routine may be called even if a previous call to `psb_info` has returned with ; indeed, it it is the only routine that may be called with argument `icontxt` in this situation.
2. A call to this routine with `close=.true.` implies a call to `MPI_Finalize`, after which no parallel routine may be called.
3. If the user whishes to use multiple communication contexts in the same program, or to enter and exit multiple times into the parallel environment, this routine may be called to selectively close the contexts with `close=.false.`, while on the last call it should be called with `close=.true.` to shutdown in a clean way the entire parallel environment.