This information is part of the Modelica Standard Library maintained by the Modelica Association.

In SPICE3 it is important to know whether a parameter was set by the user or not because the calculation of some values depends on that information and can be different. Since in Modelica there is no possibility to check that, a circumvention was chosen. The relevant parameters get an unrealistic value (-1e40) as their default value. Within a function it is checked if the parameter has still got this value (the parameter was not set by the user) of if it has a new value (parameter was set by the user).