Discussion Forum

Hi everyone,
I was wondering if anyone has tips/suggestions for optimizing solution times in Comsol 4.4? I have produced a model, which is taking far longer to solver than I would like, and I'm trying to isolate the cause. Many programing/development environments can produce breakdowns of code execution time/performance, is it possible to do this in Comsol? Perhaps via matlab or JAVA? I would like to know how much time is being spent on various tasks so I can intelligently scale back the expensive parts. For example, my model requires many function evaluations (Bessels, interpolation, ramps). I'd like to be sure that the combined execution time of these features is not the problem.

Depending on my input parameters, my model can take several minutes to run to several days. My current largest is approximately 1M DOF. The model is a 2D time-dependent simulation with coupled heat-transfer, solid-mechanics, contact, 5 domain ODE, two geometries, coupling operators and a deformed geometry. For example, one time-step of this model required six iterations of the non-linear solver (Paradiso) and took about 3 minutes on a 12-core Xeon server (with significantly more ram than required).

Is there a simple way of visualizing the Jacobian to check the sparsity? I've tried using the nojac operator to improve the sparsity of the Jacobian matrix with the coupling operators.