“…those studied in Adams (2007), Elman et al (2001), Erlangga et al (2004), Haber & Ascher (2001), Howle & Vavasis (2005), Poirier (2000) and Reitzinger et al (2003), there has been some work on the use of generalpurpose techniques such as SSOR, polynomial preconditioning, incomplete factorizations and sparse approximate inverses (see, e.g. Freund, 1990;Horesh et al, 2006;Mazzia & Pini, 2003;Mazzia & McCoy, 1999). Somewhere in between, we mention the work of Magolu monga Made (2001, e.g.…”