Johnson, C.R.Olesky, D.D.van den Driessche, P.2009-09-022009-09-0219862009-09-02http://hdl.handle.net/1828/1718enmatrix factorizationGaussian eliminationdirected graphssparse matricestechnical reports (mathematics and statistics)Technical ReportDepartment of Computer ScienceDepartment of MathematicsDepartment of Mathematics and Statistics