Default values for parameters are taken from the system.txt file either when the parameter was defined (<P>) or when it was reassigned for a parameter set (<PSET:?:?>?). These can be altered at the scripting level using this function.

system_set_guess(cfg, pname, value, lb = NULL, ub = NULL)



ubiquity system object


name of parameter to set


value to assign


optionally change the lower bound (NULL)


optionally change the upper bound (NULL)


cfg ubiquity system object with guess and bounds assigned


When performing a parameter estimation, the initial guess will be the value specified in the system.txt file for the currently selected parameter set. The following command can be used after the parameter set has been selected to specify the value (VALUE) of the parameter PNAME and optionally the lower (lb) and upper (ub) bounds:

cfg = system_set_guess(cfg, pname="PNAME", value=VALUE, lb=NULL, ub=NULL)

To set the initial guess for the parameter Vc to a value of 3, the following would be used:

cfg = system_set_guess(cfg, "Vc", value=3)

To specify the guess and overwrite the upper bound on Vc and set it to 5

cfg = system_set_guess(cfg, "Vc", value=3, ub=5)