Lulu Liu <lulu.liu at kaust.edu.sa> writes: > I want to register a new adaptive time-step scheme for the backward Euler > method. I used options: > > -ts_adapt_type myscheme -ts_theta_adapt > > The error message is show as: > > No time-step adaptivity implemented for 1st order theta method;
Please show the full error trace. Presumably you are calling TSEvaluateStep, but if you are trying to step with a first-order method, you can't use "zeroth order" as an estimate of the error. > Is there any substitute for -ts_theta_adapt such that I could have my own > time-step adaptivity for backward Euler? Why not use '-ts_type arkimex -ts_arkimex_type 1bee', which uses an extrapolation-based error estimator? If you want something else, just write it as a Runge-Kutta method like '1bee'.
