call p%apply(x,y,desc_a,info [,trans,work])
This method computes y = op(B-1) x, where B is a previously built preconditioner, stored into p, and op denotes the preconditioner itself or its transpose, according to the value of trans. Note that, when AMG4PSBLAS is used with a Krylov solver from PSBLAS, p%apply is called within the PSBLAS method psb_krylov and hence it is completely transparent to the user.
Arguments
info | x type(kind_parameter), dimension(:), intent(in)—. The local part of the vector x. Note that type and kind_parameter
must be chosen according to the real/complex, single/double
precision version of AMG4PSBLAS under use. y type(kind_parameter), dimension(:), intent(out)—. The local part of the vector y. Note that type and kind_parameter
must be chosen according to the real/complex, single/double
precision version of AMG4PSBLAS under use. desc_a type(psb_desc_type), intent(in). The communication descriptor associated to the matrix to be
preconditioned. info >>>>>> development
class="cmtt-12">integer, intent(out). >>>>>> development
class="cmr-12">Error code. If no error, 0 is returned. See Section 7 for details. trans character(len=1), optional, intent(in). If trans = ’N’,’n’ then op(B-1) = B-1; if trans = ’T’,’t’
then op(B-1) = B-T (transpose of B-1); if trans = ’C’,’c’ then
op(B-1) = B-C (conjugate transpose of B-1). work type(kind_parameter), dimension(:), optional, target—. Workspace. Its size should be at least 4 * psb_cd_get_local_
cols(desc_a) (see the PSBLAS User’s Guide). Note that type and
kind_parameter must be chosen according to the real/complex,
single/double precision version of AMG4PSBLAS under use. |