10.1 init — Initialize a preconditioner
call prec%init(icontxt,ptype, info)
- the communication context.
Specified as: an integer value.
- the type of preconditioner. Scope: global
Specified as: a character string, see usage notes.
- Scope: local
Specified as: a preconditioner data structure psb_prec_type.
- Scope: global
Error code: if no error, 0 is returned.
Notes Legal inputs to this subroutine are interpreted depending on the ptype string as
- No preconditioning, i.e. the preconditioner is just a copy operator.
- Diagonal scaling; each entry of the input vector is multiplied by the
reciprocal of the sum of the absolute values of the coefficients in the
corresponding row of matrix A;
- Precondition by a factorization of the block-diagonal of matrix A,
where block boundaries are determined by the data allocation boundaries
for each process; requires no communication. Only the incomplete
factorization ILU(0) is currently implemented.