Sundials solver options question, is dt ignored(initial step), and is maxorder a viable option? What is the default, 4?

General Usage
1

The solver compatibility chart, says that dt is ignored for sundials, is this correct? I did not see any errors when using it. Moreover, is maxorder a viable option? Is the default for CVODE_BDF 4 or 5? Can it be changed? If predicted, can we somehow find what was the decided value? If maxorder is not a viable option, is there any advise to reach to similar results?

Thanks

Christian

2

It’s 5 IIRC and it’s part of the algorithm kwargs as documented in https://diffeq.sciml.ai/latest/solvers/ode_solve/#ode_solve_sundials .

it sets the initial dt.

1 Like
3

Thank you Chris, I was using maxorder instead of max_order hoping that fixes the problem. And, yeah I do see it in the documentation , I did miss that , but other documentation that did not mention maxorder, or one that even wrote it as maxorder , rather than max_order. Also, I thought I saw a missing x , in dt for sundials. Many thanks!

Christian