What does the set_typ_vals_ode() function do?

[ensonun]

Hi,

I was wondering what the set_typ_vals_ode() function really does.

I see that it sets up the ReactorBase::m_typ_vals array, which is passed to the utils::set_sundials_solver_tols() function, which then is used to set a ratol array. However, I don't see the ratol array being used anywhere else.

I was a bit confused about the reason behind this. Or is it some legacy configuration that is no longer used?

I appreciate your help. Thank you!

[baperry2]

This is not deprecated legacy code. set_typ_vals_ode specifies a characteristic value for each species in the chemical system, which is then used in setting absolute error tolerances for the Sundials integrators. This is can be important because the orders of magnitudes for species mass fractions can range from O(1) for major species to very very tiny for radicals, so the appropriate absolute tolerance varies from species to species.

You can see where the tolerances are set for CVode or other solvers here:

PelePhysics/Source/Reactions/ReactorUtils.H

Line 148 in e371e15

flag = CVodeSVtolerances(sundials_mem, relTol, atol);

.

[ensonun]

Oh I see. ratol is the pointer to atol. Sorry I missed that. Thank you so much for the explanation.