Use a Parametric Sweep () study to find the solution to a sequence of stationary or time-dependent problems that arise when you vary some parameters of interest. The parametric sweep can include multiple independent parameters directly for a full multiparameter sweep (solve for the first value of the first parameter combined with all values of the second parameter, then the second value of the first parameter combined with all values of the second parameter, and so on, or use a specified combination of parameter values). You can also add more than one Parametric Sweep node to create nested parametric sweeps. The inner sweep in a nested parametric sweep can also be another type of sweep, such as a sweep over materials by adding a Material Sweep node below the Parametric Sweep node. The program then treats the parametric sweeps as a “nested for-loop” and indicates the nested structure using indentations of the sweep nodes’ names.

The Settings window has the following sections:

Use the Sweep type list to specify the type of sweep to perform. The Specified combinations type (the default) solves for a number of given combinations of values, while the All combinations type solves for all combinations of values. Using all combinations can lead to a very large number of solutions. The Parameter switch type makes it possible to run sweeps over selected parameter groups and associated parameter cases (see Parameters and Parameter Cases). Using the Parameter switch sweep type, you can run specified sweeps for all or selected parameter cases for a parameter group, and if you have more than one parameter group, you might want to compute all combinations of these groups. You can do so by setting up a complete parameter list as an outer sweep with all parameter groups and their parameter cases in the parameter switch table (see below). The Parameter switch sweep type can also be combined with other parametric sweeps using any sweep type.

For Specified combinations and All combinations, use the table with Parameter name, Parameter value list, and (optional) Parameter unit to specify parameter names, values, and units for the parametric solver. Use the Add button () to add a row to the table. Each row has one parameter name, a corresponding parameter value list, and an optional unit. The unit becomes orange if the unit that you specify does not match the unit given for the parameter where it is defined. For the Specified combinations sweep type, the list of values must have equal length. When you click in the Parameter value list column to define the parameter values, you can click the Range button () to define a range of parameter values. The parameter unit overrides the unit of the global parameter. If no parameter unit is given, parameter values without explicit dimensions are considered dimensionless.

For Parameter switch, add parameters to switch by clicking the Add button () to add a Parameters node in the Switch column for which to switch its parameters. In the Cases column, choose the parameter cases to include. The default is All (also when there are no parameter cases); choose User defined to specify the parameter cases to include under Case numbers. Then, during postprocessing, you can choose from the specified case numbers in lists for the added Parameters nodes under the Dataset list in the Data sections for plots and data evaluations. Use the Move Up (), Move Down (), and Delete () buttons as needed to rearrange the list of Parameters nodes for a parameter switch.

If more than one parameter name has been specified, the lists of parameter values are interpreted as follows: Assume that the parameter names are p1 and p2, and that p1 has the list 1 3 and p2 has the list 2 4. For the Specified combinations sweep type, the solver first uses p1 equal to 1 and p2 equal to 2. Thereafter, it uses p1 equal to 3 and p2 equal to 4. And when the sweep type is All combinations, the solver uses the following order for the parameter combinations: 1 2, 1 4, 3 2, and 3 4.

An alternative to specifying parameter names and values directly in the table is to specify them in a text file. Use the Load from File button () to browse to such a text file. The program appends the read parameter names, values, and units to the current table. The format of the text file must be such that the parameter names appear in the first column, and the values for each parameter appear in the next columns, comma separated (1,3,5) or separated with a space, row-wise enclosed with quotation marks and with spaces separating the values (such as "1 3 5"). Finally (separated by a space), the format includes an optional unit using unit syntax such as [m/s]. Click the Save to File button () to save the contents of the table to a text file (or to a Microsoft Excel Workbook spreadsheet if the license includes LiveLink™ for Excel®).

You can use the Keep solutions list under Memory settings for jobs to control how to store the solutions from the individual parametric sweep solutions. Select All to store all the parametric sweep solutions in memory, or select Only last to store only the last solution from the parametric sweep. If you select Only last and the parametric solver is used, all solutions are kept in memory. When only the last solution is stored, you can also select the Save each solution as model file check box. It stores the separate parametric sweep solutions and their corresponding models in separate MPH-files. Enter a filename in the Filename field or click Browse to choose a name and location for the model files. Click the downward arrow for the File Location Actions menu () to choose Copy File Location () and (if you have copied a file location) Paste File Location (). You can also use probes to collect some solution values of interest during the sweep rather than storing all solutions, which can save memory and solution time.

Select the Plot check box to allow plotting of results while solving. Then select what to plot from the Plot group list. The software plots the dataset of the selected plot group as soon as the results become available.

Use the Probes list to select probes to update during the parametric sweep. The default is All, which selects all probes for plotting and tabulation of probe data. Select Manual to open a list with all available probes. Use the Move Up (), Move Down (), Delete (), and Add () buttons to make the list contain the probes that you want to see results from while solving. Select None to disable probe updating for parametric sweep. Note that the control of tables and plot windows is done using the probe settings.

Select the Accumulated probe table check box to activate the accumulation of probe updates for both the variation on the solver level (time, frequency, and so forth) and on the parametric sweep level. Use the Output table to select where to put the data. Select the Use all probes check box if all the model probes should be accumulated in the table. If not selected, the probes selected from the Probes list are used.

The Keep reduced-order models check box is selected by default. Then, these additional settings are available:

From the Use parametric solver list, select one of the following options:

From the Default solver sequence generation list, select one of the following options:

From the Default solver sequence generation list you can control when a solver sequence should be generated during a parametric sweep (see also the settings for the Solution node under Job Configurations):

By default, the solver sequence builds meshes based on the values of the global parameters. These meshes can then influence the generated solver sequence. In some cases, the global parameter values could lead to invalid meshes. Also, the solver sequence is, in the default case, optimized for the global parameter values, which could lead to another choice of solver than the preferred solver. Using one of the other available options in the Default solver sequence generation list can avoid such behavior.

Select the Reuse solution from previous step check box, if you want to reuse the converged values of variables from the previous sweep step as initial condition for the next step during the sweep. If a Parametric Sweep study step wraps an Optimization study step, select this check box to reuse variables solved for (both control variables and PDE variables) from the previous converged optimization call. This option is useful for parameters not handled with continuation. See Reuse Solution from Previous Step List for information about reusing solutions.

If you are running a parametric sweep and want to distribute it by sending one parameter value to each compute node, select the Distribute parametric sweep check box. To enable this option, click the Show More Options button () and select Solver and Job Configurations in the Show More Options dialog box. Note that if the Distribute parametric sweep check box is selected, Solution under Initial values of variables solved for in the Values of Dependent Variables section in the study step node’s settings cannot be set to Current. Each node is assigned disjoint sets of parameters; hence, the initial solution is undefined for all nodes other than the first.