I have 2*m+3 STIFF ordinary differential equations to be solved. I have tried to solve it using MATLAB ode15s for m=1 and it works fine. But I would like to use Sundials package CVODE to solve the equations. While trying to do so, I used 'backward differentiation formulae' and Newton iteration. I do not supply the jacobian and allow it to be computed numerically. but it is not working and shows the error:
[CVODE WARNING] CVode
Internal t = 0 and h = 0 are such that t + h = t on the next step. The solver will continue anyway.
[CVODE ERROR] CVode
At t = 0 and h = 0, the correction convergence test failed repeatedly or with :h: = hmin.
SUNDIALS_ERROR: CVode<> failed with flag -4
- I believe that CVODE uses the same backward differentiation as ode15s. Then why is it not working?
- Should I try to use Krylov solver with preconditioning in CVODE?
Looking forward for any help. Thank you.
