The Numerical Solution of Separably Stiff Systems by Precise Partitioning
David S. Watkins, Ralph W. HansonSmith · ACM Transactions on Mathematical Software · 1983
Bell StiffMost codes for solving stiff systems of ordinary &fferentlal equations spend most of their time solving systems of linear equations with coefficient matrix I -hflJ, where J is the Jacobian matrix of the system The precise partltmning method solves these systems approxamately by partitioning the Jaeobian into stiff and nonstiff parts The method resembles a method proposed by Enright and Kamel [ACM Transactmns on Mathemattcal Software 5, 4(Dec.1979), 374-385], but chffers in that the partition of the Jacobmn matrix is more precise In this paper the method is implemented by revising a popular code.Numermal results inchcate that for systems of more than about ten equations with few stiff eigenvalues, the precise partitmning method can save CPU time compared to the unmodified code.