Method smoothers

This method builds the smoothers and the coarsest-level solvers for the multilevel preconditioner p, according to the requirements made by the user through the methods init and set, and based on the aggregation hierarchy produced by a previous call to hierarchy_build (see Section 5.3).

`a`	`type(psb_`x`spmat_type), intent(in)`.
	The sparse matrix structure containing the local part of the matrix to be preconditioned. Note that x must be chosen according to the `real`/`complex`, single/double precision version of AMG4PSBLAS under use. See the PSBLAS User’s Guide for details [21].
`desc_a`	`type(psb_desc_type), intent(in)`.
	The communication descriptor of `a`. See the PSBLAS User’s Guide for details [21].
`info`	`integer, intent(out)`.
	Error code. If no error, 0 is returned. See Section 7 for details.
`amold`	`class(psb_`x`_base_sparse_mat), intent(in), optional`.
	The desired dynamic type for internal matrix components; this allows e.g. running on GPUs; it needs not be the same on all processes. See the PSBLAS User’s Guide for details [21].
`vmold`	`class(psb_`x`_base_vect_type), intent(in), optional`.
	The desired dynamic type for internal vector components; this allows e.g. running on GPUs.
`imold`	`class(psb_i_base_vect_type), intent(in), optional`.
	The desired dynamic type for internal integer vector components; this allows e.g. running on GPUs.

5.4 Method smoothers_build