4.2 GPU example

The code reported in Figure 5 shows how to set up a program exploiting the combined GPU capabilities of PSBLAS and AMG4PSBLAS.


! build a one-level RAS with overlap 2 and ILU(0) on the local blocks.
call P%init(’AS’,info)
call P%set(’SUB_OVR’,2,info)
call P%build(A,desc_A,info)
... ...
! solve Ax=b with preconditioned BiCGSTAB
  call psb_krylov(’BICGSTAB’,A,P,b,x,tol,desc_A,info)


Listing 5: setup of a one-level Schwarz preconditioner.