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Optimization runs slowly
Optimization > Troubleshoot optimization > Optimization runs slowly

This often means that the model also runs slowly in Simulator. Some models contain very rapid changes in the species concentrations or other variables being integrated by the solver. The solver will therefore need to take very small timesteps to capture these rapid changes, which results in a longer run time.

Typical examples include fast reactions (e.g. pH adjustment/ neutralization, ionic equilibria); fast mass transfer (high kLa to ensure equilibrium between phases), models where phases appear or disappear. The variable causing the small timestep can be seen by viewing the Event Log in Simulator. This should give some indication of the source of the problem.

To correct this, try modifying the model (either reduce very large parameter values or simplify the model). If this cannot be done, some other options are available to reduce run-times: