I’m trying to use the optimizer (lbfgs and bfgs) and keep getting the following error: (these are the final lines of the cmdstan output)
Iter log prob ||dx|| ||grad|| alpha alpha0 # evals Notes
189 1248.86 0.0257983 27.3849 1 1 242
Iter log prob ||dx|| ||grad|| alpha alpha0 # evals Notes
190 1248.87 1.87757e-05 23.6615 6.856e-07 0.001 286 LS failed, Hessian reset
Iter log prob ||dx|| ||grad|| alpha alpha0 # evals Notes
191 1248.87 1.87757e-05 23.6615 5.206e-11 0.001 357 LS failed, Hessian reset
Optimization terminated with error:
Line search failed to achieve a sufficient decrease, no more progress can be made
Does anyone have any advice on how to avoid this? The model is quite complex and uses and uses the ODE solver. Even though the optimizer terminates with an error, the fit goes through the data quite well. Is there perhaps a way to tweak the tolerances in some way? I’m using the default values.