IDA provides a default Newton method (Modified Newton with no globalization) for solving the nonlinear algebraic system at every timestep. However, IDA also implements a Newton+Linesearch algorithm which is (as far as I can tell) only used from within IDACalcIC, and cannot be selected as the nonlinear solver for the per-timestep systems.

Is there a deep reason for not using linesearch globalization with the systems that IDA produces ? I am considering implementing a custom SUNNonlinearSolver to do some sort of parallelized Newton+LS and wondered if this was known to be a bad idea :)