Using selective save

selective save

Many simulations produce result files, which are relatively small, even though you have stored all the results. As the systems you study get bigger, you will reach a stage when the size of the result files you create becomes embarrassingly large! At this stage you need to save a subset of the results. We call this facility selective save.

By default all variables are saved in the result file. You can specify precisely which variables you want to be saved. This can be done:

• Globally for a collection of selected components and line runs or for the whole system.

• For a particular submodel.

• For an individual variable.

Results

All changes to the save status of variables are made in Simulation mode.

To change the save status globally

Save next status global change

Procedure

1. Select a component, several components or the whole system (Ctrl+A).

2. Right-click the selection to call the contextual menu:

Figure 37: Settings menu

3. Select Save all variables to ensure ALL variables of the selected items are saved, orSelect Save no variables to ensure NO variables of the selected items are saved.

To change the save status of all variables of a particular submodel

Save next status submodel change

Procedure

1. Right-click and select Save all/no variables, orDouble-click on the appropriate component or line run to produce the Variable list dialog box.

2. Click on Save all to save all the variables of that submodel, orClick on Save none to save none of the variables of that submodel.

To change the save status of a particular variable:

Save next status individual variable change

Procedure

1. Single-click on the component or line which contains the variable and use the Save next checkbox in the Contextual parameters view window, or Double-click on the component or line which contains the variable to display the Variable list dialog box.

2. Select the Save next checkbox of the variable you want to save, and/orRemove the tick mark in the Save next checkbox of any variable you do not want to save.

In the current example

Procedure

1. In Simulation mode use Ctrl+A.

2. From the Settings menu select Save no variables and do a dynamic run.

3. Next try to plot some graphs.

You will find it impossible. This is an extreme situation and the only point of doing a simulation with no variables saved is for linearizing the system. This is the subject of another section in this manual.

4. Select the Body mass component and note all the Saved check boxes are disabled.

5. Right-click on the component, select Save all variables and do a run.

6. Verify that you can now plot any variable for this component (except for the forces which are computed by connected components).

7. Finally select Save no variables for this component.

8. Tick the body displacement Save next box (see figure below).

Figure 38: Save next and Saved columns

9. Do a run and verify that you can plot body displacement but no other Body mass variable.

Saved column

Saved column

When you perform a run and decide not to save some of the variables, the Saved column checkboxes for those (unsaved) variables (figure below) are unticked. Note that Saved is a status that applies to the previous run. Note also that the final values of the variables that are not saved are displayed in the Value column.

Figure 39: Saved column applies to the previous run

Experiment by changing the Save next status of variables at the submodel and individual variable level.

The big advantage of the selected save is for batch runs. If you want, you can do 50 consecutive runs varying one or more parameters. It would be undesirable to produce 50 full size results files for a very big system!