Reactive transport in surface sediments. I. Model complexity and software quality

Abstract

Analysis of three recent diagenetic model codes (OMEXDIA, CANDI and STEADYSED) revealed that codes have a rigid, static and problem-specific character, leaving little autonomy for the application user. The resulting lack of flexibility and extensibility, and the associated need for ground-level reprogramming, constitutes a major barrier for potential model users. Present codes have apparently passed a critical threshold of code complexity, above which code development becomes time-consuming and expensive using the present procedure-oriented techniques. We have explored the advantages of object-oriented technology and the concept of a problem-solving environment to improve the quality of software for reactive transport modelling. A general blueprint for an object-oriented code for modelling early diagenesis is presented. The MEDIA environment consists of a toolbox of building blocks (element, species and process objects), which can be combined freely by the user to construct new models (without the need for recompilation). An object-oriented database stores current objects and accommodates new user-defined building blocks. Altogether, it is advocated that by improving the software quality, one can substantially lower the threshold for using model codes as an integrated data-analysis tool [KEYWORDS: Reactive transport modelling; Early diagenesis; Object-oriented design; Problem-solving environment; Software quality assurance]