## About DAETS

DAETS, Differential-Algebraic Equations (DAEs) by Taylor Series, is a C++ package for solving initial value problems for DAE systems. Developed jointly by Ned Nedialkov at McMaster University, Canada, and John Pryce at Cranfield University, UK, DAETS is based on Pryce's method for the structural analysis of DAEs. This is a powerful way to determine the index of the system, its number of degrees of freedom, and exactly which components should be given initial values. The results of the structural analysis can be printed out by the user's program as a useful aid to understanding a DAE problem.

A DAE can be encoded in a form very close to its mathematical description. There is no need to convert it to a form that involves only first derivatives, nor to use index-reduction techniques.

Finding an initial consistent point for a DAE is often difficult, especially for nonlinear problems. DAETS has a robust and reliable method for doing so automatically.

DAETS has been used to solve a range of nontrivial problems, including chemical, mechanical and electrical system examples from the "ODE/DAE Test Set for Initial Value Problem Solvers", DAEs of index up to 47, and difficult continuation problems. It has been found easy to use by students in a graduate course on scientific computing.

### Authors

Ned Nedialkov Dept. of Computing and Software McMaster University Hamilton, ON, L8S 1H2 CANADAJohn Pryce 46 Ponting Street

Swindon

Wiltshire, SN1 2BW UK