Parametric Runs
Previous (Topics on IDA Usage) | Back to Start | Next (Graphical Scripts)
Parametric runs
The IDA “Parametric runs” allows,
• Running a series of simulations with a systematic variation of parameters and/or other changes in a data structure (inserting or replacing different objects).
• Running optimization tool
• Visualization of simulation results
Access to Parametric runs case
A Parametric runs case is an object that describes a series of parametric runs and keeps the simulation results.
To open an existing or create a new parametric run case, select “Parametric runs” from the Tools menu. The form of Fig. 60 will be opened.
To copy or remove a case, select the submenu “Parametric runs” -> “Organize” from the same menu.
Figure 60. Parametric run form
Preparing input
In “General” tab, select
• Case name and optional description
• Select “Yes” in Keep generated models if you want to know that data are being saved for all models of parametric runs after running.
• List of modifications to the system (Input).
• List of variables that should be reported in the summary or used for optimization (Output)
The list of modifications (input) may include
• Non-protected scalar parameters (or elements of array parameters) from the IDA system. The start values of variables are treated as parameters.
• Special parameters that denote custom modifications.
To add a parameter, do one of the following:
• Select a parameter and choose the menu item “Add to parametric Runs” from the context menu. If the system contains multiple targets for “Add to”, select the desired one from the menu.
• Drag one or more fields with parameter values from a form and drop them to the “Input” field. In the same way, a parameter may be dragged from the outline view.
• Copy one or more fields or a parameter to the clipboard; then click “+” and select “from clipboard” in the menu
• Click “+” and select “browse” to choose a parameter or “custom” to add a particular parameter.
Fill the columns in the Input table with the following information:
• Value – the base value of the parameter;
• Range – for numerical parameters: [min max]. Alternatively, enter the complete list of values (v_1 v_2 … v_n); in this case, the next two columns are not used;
For enumeration and resource parameters, click the cell and mark the appropriate alternatives.
• Distribution – select how the parameter values are distributed inside the range(for numerical parameters only). Three alternatives are currently supported: uniform, log-uniform, and triangle (tighter around the base value)
• Resolution – the number of points in the range (for numerical parameters only)
It is also possible to replace the parameter by clicking the cell “Target”
The list of results (output) may contain
• References to any object in the IDA system.
The results items are added in the same way as the input items.
The Target and Range cells in the Input list and Function cells in the Output can be filled by scripts or functions that perform custom modifications or definitions. These may depend on previous parameters or elements in the list. For further information, refer to Link.
Run simulations
Click “Run all” to run all defined combinations of parameter values. The simulations are performed by child processes. The maximal number of child processes is defined in the Preferences dialog
Click “Run optimization” to select and run an optimization tool. AutoMOO optimization is briefly discussed here. (Link)
Click "Monte Carlo" to run the given number of simulations with a random choice of parameter values. The distribution of parameter values is given in columns "Range" and "Distribution".
Click "Sensitivity analysis" to run a simulation with given values of all parameters, and then for every parameter, run two simulations with the parameter value changed to its minimal and maximal value (for a discrete parameter, a simulation is performed for every value in the range). In contrast, other parameters keep their given values.
Results
The field Summary shows the values of all input and output variables in all simulations.
Double-click a label to open the simulation case. If the cases were saved (option Keep generated models = Yes), the saved case is loaded. Otherwise, the case is re-created without the simulation results.
Under the result tab of the parametric runs, to see the results graphically, open a diagram or click “+” to create a new one. You can observe the result generation as the simulations are being executed.
When creating a diagram, in the “Design diagram” dialog, select how to show input and output data.
Click the cell “Show as” to select the visualization mode. Use one of the following options:
• Select “x-axis” and “y-axis” for two result variables and “area” for some other results and parameters
• Select “x-axis” and “y-axis” for two result variables; “area” for one real input or result; “color” and “shape” for two discrete input
• Select “x-axis” for one result variable and “y-axis” for multiple result variables with the same quantity type. The choices “area”, “color”, “shape” may also be used for other parameters/variables, but they will be shown with the first y-variable. Use keyboard keys Alt+Up and Alt+Down to reorder the variables.
• One of the above, without selecting a variable for the “x-axis”. In this case, the simulation number will be shown along the x-axis.
When a diagram is open, point with the mouse to the center of a spot representing a simulation to see the details. They may be open by right-clicking the spot and selecting “Open” from the context menu.