I recently became aware of this paper by Francesco Casella regarding "Simulation of Large-Scale Models in Modelica: State of the Art and Future Perspectives" where the lack of Sparse DAE Solvers to work with large Modelica models is addressed. Coming from the System Dynamics - Community, which makes use of ODE/DAE-Modeling in the social sciences and business, I noted that this very feature has been recently implemented by Ventana, a specialized software firm for SD-tools, in their new release of Ventity, an object-oriented simulation tool, that allows sparse structures and dynamic generation of objects/entities.
So the question is: Are there sparse DAE solvers available to simulate SystemModeler-models - especially using Mathematica to do simulation and analysis?
While this is related to an earlier question I posted regarding variable-structure systems, I would like to make this a separate, concise question.
WSM supports the CVODES solver. CVODES is a sparse DAE solver. I do not know if WSM uses the sparse features in CVODES -- the developers would have to answer that question.
Sparsity is utilized in in several ways by SystemModeler. First, the symbolic processing applies standard techniques such as transformation into block lower triangular form and tearing. Then, sparsity of linear equation systems at runtime are handled using techniques for sparse linear algebra.