Question How big a finite element model can the SDT handle ?
Answer On 64 bit architectures (windows or linux), large models (between 1e5 and 1e6 DOFs) can generally be handled practically. Very large models (several 1e6 DOF) imply great care and can typically only be handled when using the SDT out-of-core capabilities (see sdthdf) to off-load part of the data to a database file.
On 32 bit systems, the real limit is linked to the fact that MATLAB uses 32 bit addressing so that a single matrix can't be bigger than 2 GB. Furthermore, due to memory segmentation, it is difficult to use memory segments (matrices) that are above a couple 100MB (much below the theoretical 2 GB limit). The SPFMEX library used by SDT to provide efficient sparse matrix solutions generates significant fragmentation. This typically limits the maximum model size one a 32 bit architecture to a couple 100,000 DOFs.
Note that handling large models requires to take precautions about not duplicating matrices, ... The SDT is very flexible but if you want to strain the resources of your computed you should be careful.
