We present a case study of the alternatives and design trade-offs encountered when adapting an established numerical library into a form compatible with modern component-software implementation practices. Our study will help scientific software users, authors, and maintainers develop their own roadmaps for shifting to component-oriented software. The primary library studied, LSODE, and the issues involved in the adaptation are typical of many commonly used numerical libraries. We examine the adaptation of a related library, CVODE, and compare the impact on applications of the two different designs.

The LSODE-derived components solve models composed with CCA components developed independently at the Argonne and Oak Ridge National Laboratories. The resulting applications run in the Ccaffeine framework implementation of the Commmon Component Architecture specification. We provide CCA-style interface specifications appropriate to linear equations, ordinary differential equations (ODE), and differential algebraic equations (DAE) solvers.