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Preconditioner data structure

Our base library offers support for simple well known preconditioners like Diagonal Scaling or Block Jacobi with incomplete factorization ILU(0).

A preconditioner is held in the precdata psb_prec_type data structure reported in figure 5. The psb_prec_type data type may contain a simple preconditioning matrix with the associated communication descriptor.The values contained in the iprcparm and rprcparm define tha type of preconditioner along with all the parameters related to it; thus, iprcparm and rprcparm define how the other records have to be interpreted. This data structure is the basis of more complex preconditioning strategies, which are the subject of further research.

Figure 5: The PSBLAS defined data type that contains a preconditioner.