Solutions to intermediate evaluation by CVODE are leaking to algebraic loop solutions

[rruusu]

Description

The initial guesses for each algebraic loop evaluation are not based on the end of the last solver step. Instead, the initial guess is based on whatever result was last obtained by the previous RHS evaluation of the ODEs, which might be related to a trial step in Jacobian evaluation using difference quotient steps.

This results in both unnecessary noise to inputs in algebraic loops, as well as possible extra iterations.

Version and OS

• Version: OMSimulator v2.1.2.post5-gce342b6-mingw-notlm-debug
• OS: Windows 11, 64-bit

[rruusu]

I will push a solution for this to my fork shortly.