Parameter

In OpenSHA a parameter is virtually any entity that has or specifies the following:

• Name - the name of the parameter (e.g., "Peak Ground Acceleration")
• Type - the type of parameter (e.g., double-precision number)
• Units - the units if applicable (e.g., "g")
• Value - the currently set value (e.g., 1.0)
• Constraint - the allowed values (e.g., ≥ 0)
• Info - a sentence describing the parameter (used for mouse overs)

A parameter might be simple numeric value (as in the example above) or a simple string (e.g., for a "rock" versus "soil" description of a Site).

However, nothing limits the potential complexity of a Parameter in OpenSHA. In fact, we presently have a "Magnitude Frequency Distribution" Parameter and a "Fault" parameter.

This generality helps maintain our plug and play flexibility (e.g., so new model components can be added to an application without having to rewrite the source code for that application). For example, when a user chooses a particular ERF in our Hazard Curve Calculator, the application simply requests the list of adjustable parameters from the ERF and puts these in a window for the user to edit. The application doesn't need to know any details about these parameters (including whether the author recently added or removed any from the list).

Some parameters also have a Warning Constraint, where if you set the value outside this range a warning message will be dispatched.