Clarification around Parameter Estimation Variables

[Theo-BRN]

Hey Frank,

I noticed that plot per experiment doesn't seem to return the current fit, if, randomize_start_values was set to True in the last run_parameter_estimation.

Additionally I was getting a bit confused with the rationale behind parameters 'storage' in parameter estimation, and I wondered if you could clarify some assumptions for me.

• After running a simulation, is the solution stored in some kind of PE object, or just the output of the function itself?
• Does the 'update_model' function argument, update the qlobal quantities or update the PE object with the solution?
  • It seems my model parameters change even though update_model is set to False
• My overall assumption would be that some kind of PE object or class instance stores the solution to parameter estimation runs. And when setting update_model to True, you effectively run set_parameters(...) for those particular parameters, changing the global quantities to the solution parameters.

Thanks for any help you can offer with this! Hope you're doing well :-)

Best,
Theo

[fbergmann]

Thanks for filing this issue let me get to the points in turn

• the one thing for basico to change is clearly, that the plot functions (or rather get_current_solution) clearly needs to temporarily disable randomize_start_values. Because of the randomization, you are likely to hit an infeasible solution which results in you not getting a simulation result.

as to your questions about storage. All tasks in COPASI just modify the current models state. If update_model=False, then the initial state remains the same, and the task is just modifying the transient state. If update_model is true, then the final transient state becomes the new *initial state.

so for this issue i'll change basico, to not randomize values for the current result ever, which will solve the issue you were having with plots.

[fbergmann]

I have released a new basico version, that ensures that get_simulation_resutls no longer uses random start values.