Simple FEMs aren’t as good as we thought: experiences developing EIDORS v3.3

In this paper, we 1: announce EIDORS version 3.3, and clarify the new features and changes to the software. Briefly, the new version includes: a) interfaces to FEM generation (distmesh, netgen) and dual model solvers, b) new algorithms (total variation, electrode movement solver, temporal solvers), c) a data repository with in vivo and simulated data and models, d) faster algorithms with better caching, and e) improved graphics and extensive tutorials. 2: we review the use of dual models in EIT, and the architecture to support their use in EIDORS. 3: we discuss accuracy limitations to the single-order tetrahedral finite element models that are used in much EIT research. We recommend that models be used of at least 10 elements (for 2D FEMs) and 10 elements (for 3D FEMs). FEM accuracy may be partially addressed using dual model solvers, for which EIDORS v3.3 provides support. Systems and Computer Engineering, Carleton University, Ottawa, Canada Thayer School of Engineering, Dartmouth College, Hannover, NH, USA School of Engineering, Massachusetts Institute of Technology, Boston, USA School of Mathematics, University of Manchester, UK