Method apply

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.

`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`	`integer, intent(out)`.
	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.

5.6 Method apply