that is : good enough to pass PQC = personal qualitiy control *sigh* before peach freeze some of them almost did .. but hey we want to give 'em peachers something to rely on not a mushy "may be it works" so 'implicit solver' is gone for now and from what i read between the lines in various papers the main problem is the Jacobian has negative 'eigenvalues' yeah that rings a bell .. the transition from a continuous system to a discrete one bears that. /* you did not read/understand that .. fine .. because this is something that might give me my late PhD */