Logged Data Size and Location

By default, simulation data logs to disk with data loaded into memory on demand, and the maximum size of logged data is constrained only by available disk space. You can use the Disk Management settings in the Simulation Data Inspector to directly control the size and location of logged data.

The Record mode setting specifies whether logged data is retained after simulation. When you change the Record mode setting to View during simulation only, no logged data is available in the Simulation Data Inspector or the workspace after the simulation completes. Only use this mode when you do not want to save logged data. The Record mode setting reverts to View and record data each time you start MATLAB. Changing the Record mode setting can affect other applications, such as visualization tools. For details, see View Data Only During Simulation.

To directly limit the size of logged data, you can specify a minimum amount of free disk space or a maximum size for the logged data. By default, logged data must leave at least 100 MB of free disk space with no maximum size limit. Specify the required disk space and maximum size in GB, and specify 0 to apply no disk space requirement or no maximum size limit.

When you specify a minimum disk space requirement or a maximum size for logged data, you can also specify whether to prioritize retaining data from the current simulation or data from prior simulations when approaching the limit. By default, the Simulation Data Inspector prioritizes retaining data for the current run by deleting data for prior runs. To prioritize retaining prior data, change the When low on disk space setting to Keep prior runs and stop recording. You see a warning message when prior runs are deleted and when recording is disabled. If recording is disabled due to the size of logged data, you need to change the Record Mode back to View and record data to continue logging data, after you have freed up disk space. For more information, see Specify a Minimum Disk Space Requirement or Maximum Size for Logged Data.

The Storage Mode setting specifies whether to log data to disk or to memory. By default, data logs to disk. When you configure a parallel worker to log data to memory, data transfer back to the host is not supported. Logging data to memory is not supported for rapid accelerator simulations or models deployed using Simulink^® Compiler™.

You can also specify the location of the temporary file that stores logged data. By default, data logs to the temporary files directory on your computer. You may change the file location when you need to log large amounts of data and a secondary drive provides more storage capacity. Logging data to a network location can degrade performance.

Archive Behavior and Run Limit

When you run multiple simulations in a single MATLAB session, the Simulation Data Inspector retains results from each simulation so you can analyze the results together. Use the Simulation Data Inspector archive to manage runs in the user interface and control the number of runs the Simulation Data Inspector retains.

You can configure a limit for the number of runs to retain in the archive and whether the Simulation Data Inspector automatically moves prior runs into the archive.

Incoming Run Names and Location

You can configure how the Simulation Data Inspector handles incoming runs from import or simulation. You can choose whether new runs are added at the top of the work area or the bottom and specify a naming rule to use for runs created from simulation.

By default, the Simulation Data Inspector adds new runs below prior runs in the work area. The Archive settings also affect the location of runs. By default, prior runs are moved to the archive when a new simulation run is created.

The run naming rule is used to name runs created from simulation. You can create the run naming rule using a mix of literal text that is used in the run name as-is and one or more tokens that represent metadata about the run. By default, the Simulation Data Inspector names runs using the run index and model name: Run <run_index>: <model_name>.

Signal Metadata to Display

You can control which signal metadata is displayed in the work area of the Inspect pane and in the results section on the Compare pane in the Simulation Data Inspector. You specify the metadata to display separately for each pane using the Table Columns preferences in the Inspect and Compare sections of the Preferences dialog, respectively.

Signal Selection on the Inspect Pane

You can configure how you select signals to plot on the selected subplot in the Simulation Data Inspector. By default, you use check boxes next to each signal to plot. You can also choose to plot signals based on selection in the work area. Use Check Mode when creating views and visualizations that represent findings and analysis of a data set. Use Browse Mode to quickly view and analyze data sets with a large number of signals.

For more information about creating visualizations using Check Mode, see Create Plots Using the Simulation Data Inspector.

For more information about using Browse Mode, see Visualize Many Logged Signals.

How Signals Are Aligned for Comparison

When you compare runs using the Simulation Data Inspector, the comparison algorithm pairs signals for signal comparison through a process called alignment. You can align signals between the compared runs using one or more of the signal properties shown in the table.

You can specify the priority for each piece of metadata used for alignment. The Align By field specifies the highest priority property used to align signals. The priority drops with each subsequent Then By field. You must specify a primary alignment property in the Align By field, but you can leave any number of Then By fields blank.

By default, the Simulation Data Inspector aligns signals between runs according to this flow chart.

For more information about configuring comparisons in the Simulation Data Inspector, see How the Simulation Data Inspector Compares Data.

Colors Used to Display Comparison Results

You can configure the colors used to display comparison results using the Simulation Data Inspector preferences. You can specify whether to use the signal color from the Inspect pane or a fixed color for the baseline and compared signals. You can also choose colors for the tolerance and the difference signal.

By default, the Simulation Data Inspector displays comparison results using fixed colors for the baseline and compared signals. Using a fixed color allows you to avoid the baseline signal color and compared signal color being either the same or too similar to distinguish.

Signal Grouping

You can specify how to group signals within a run in the Simulation Data Inspector. The preferences apply to both the Inspect and Compare panes and comparison reports. You can group signals by:

Grouping signals adds rows for the hierarchical nodes, which you can expand to show the signals within that node. By default, the Simulation Data Inspector groups signals by domain, then by physical system hierarchy (if you have a Simscape license), and then by data hierarchy.

To remove grouping and display a flat list of signals in each run, select None for all grouping options.

Data to Stream from Parallel Simulations

When you run parallel simulations using the parsim function, you can stream logged simulation data to the Simulation Data Inspector. A dot next to the run name in the Inspect pane indicates the status of the simulation that corresponds to the run, so you can monitor simulation progress while visualizing the streamed data. You can control whether data streams from a parallel simulation based on the type of worker the data comes from.

By default, the Simulation Data Inspector is configured for manual import of data from parallel workers. You can use the Simulation Data Inspector programmatic interface to inspect the data on the worker and decide whether to send it to the client Simulation Data Inspector for further analysis. To manually move data from a parallel worker to the Simulation Data Inspector, use the Simulink.sdi.sendWorkerRunToClient function.

You may want to automatically stream data from parallel simulations that run on local workers or on local and remote workers. Streaming data from both local and remote workers may affect simulation performance, depending on how many simulations you run and how much data you log. When you choose to stream data from local workers or all parallel workers, all logged simulation data automatically shows in the Simulation Data Inspector.

Signal Display Units

Signals in the Simulation Data Inspector have two units properties: stored units and display units. The stored units represent the units of the data saved to disk. The display units specify how the Simulation Data Inspector displays the data. You can configure the Simulation Data Inspector to use a system of units to define the display units for all signals. You can choose either the SI or US Customary system of units, or you can display data using its stored units.

When you use a system of units to define display units for signals in the Simulation Data Inspector, the display units update for any signal with display units that are not valid for that unit system. For example, if you select SI units, the display units for a signal may update from ft to m.

In addition to selecting a system of units, you can specify override units so that all signals of a given measurement type are displayed using consistent units. For example, if you want to visualize all signals that represent weight using units of kg, specify kg as an override unit.

You can also modify the display units for a specific signal using the Properties pane. For more information, see Modify Signal Properties in the Simulation Data Inspector.