An initialization subroutine for DAEs solvers: DAEIS

Numerical difficulty arises when DAEs are solved with inconsistent initial values of dependent variables. II can cause the solution failures of many p opular DAEs solvers. An initialization subroutine, DAEIS (Differential Alge braic Equations Initialization Subroutine), has been developed to handle th is issue. In DAEIS, consistent initial values of dependent variables for in dex-1 DAEs are obtained through solving a set of nonlinear equations based on the initialization settings. To achieve good efficiency and robustness o f the initialization computation, a nonlinear equation solver, GNES, has be en specially built for DAEIS. The usage of DAEIS is demonstrated through ha ndling inconsistent initializations for combined continuous/discrete simula tions. (C) 2001 Elsevier Science Ltd. All rights reserved.