getElement

When you have data that is stored in the Simulation Data Inspector repository, but not in the workspace, you can use the getElement function to return a copy of the signal data to the workspace. In this example, a Simulation Data Inspector session file is used to add run data to the repository. The data is not loaded to the workspace. The session file contains data for four simulations of an aircraft longitudinal controller. For more information about the model used to create the data, see Aircraft Longitudinal Flight Control.

Use the Simulink.sdi.load function to load the Simulation Data Inspector session. When you load the session file, run data is saved to the Simulation Data Inspector repository.

Simulink.sdi.load("AircraftExample.mldatx");

To view the data, open the Simulation Data Inspector and select signals to plot. Note that the data from the Simulation Data Inspector session file is not recorded in the workspace.

Simulink.sdi.view

Get the run ID for the first run saved in the session file.

allIDs = Simulink.sdi.getAllRunIDs;
aircraftRun1ID = allIDs(end-3);

Create a Simulink.sdi.DatasetRef object that references that run.

dsr = Simulink.sdi.DatasetRef(aircraftRun1ID);

Get the names of all the elements in the DatasetRef object.

getElementNames(dsr)

ans = 3x1 cell
    {'q, rad/sec'}
    {'alpha, rad'}
    {'Stick'     }

Use the getElement function to pull a copy of the q, rad/sec signal data that is located in the Simulation Data Inspector repository into the workspace using the index 1.

qSig = getElement(dsr,1)

qSig = 
  Simulink.SimulationData.Signal
  Package: Simulink.SimulationData

  Properties:
              Name: 'q, rad/sec'
    PropagatedName: ''
         BlockPath: [1x1 Simulink.SimulationData.BlockPath]
          PortType: 'outport'
         PortIndex: 3
            Values: [1x1 timeseries]

The model GetDatasetElements logs data generated by three source blocks using the Dataset format. In the model, the signals coming from the Sine Wave block and the Constant block share the same name. The signal coming from the Pulse Generator block has a unique name.

open_system("GetDatasetElements")

Simulate the model.

out = sim("GetDatasetElements");

Use the Simulink.sdi.Run.getLatest function to get the latest run in the Simulation Data Inspector repository.

GDERun = Simulink.sdi.Run.getLatest;

Create a Simulink.sdi.DatasetRef object that references GDERun.

DSRef = getDatasetRef(GDERun);

Use the getElement function to return a copy of the data from the signal with the name DifName to the workspace. Because the name DifName is unique, the function returns a Simulink.SimulationData.Signal object for that signal.

[el,difName,difIndex] = getElement(DSRef,"DifName")

el = 
  Simulink.SimulationData.Signal
  Package: Simulink.SimulationData

  Properties:
              Name: 'DifName'
    PropagatedName: ''
         BlockPath: [1x1 Simulink.SimulationData.BlockPath]
          PortType: 'inport'
         PortIndex: 1
            Values: [1x1 timeseries]

difName = 
'DifName'

difIndex = 
2

You can also use the getElement function when a signal name is not unique within a run. For example, because SameName is not a unique name, the function returns a copy of the data for the signals with that name to the workspace in a Simulink.SimulationData.Dataset object.

ds = getElement(DSRef,"SameName")

ds = 
Simulink.SimulationData.Dataset '' with 2 elements

                         Name      BlockPath               
                         ________  _______________________ 
    1  [1x1 Signal]      SameName  GetDatasetElements/Out1
    2  [1x1 Signal]      SameName  GetDatasetElements/Out2

  - Use braces { } to access, modify, or add elements using index.

The model GetDatasetElements logs data generated by three source blocks using the Dataset format. In the model, the signals coming from the Sine Wave block and the Constant block share the same name. The signal coming from the Pulse Generator block has a unique name.

open_system("GetDatasetElements")

Simulate the model.

out = sim("GetDatasetElements");

Use the Simulink.sdi.Run.getLatest function to get the latest run.

GDERun = Simulink.sdi.Run.getLatest;

Create a Simulink.sdi.DatasetRef object that references GDERun.

DSRef = getDatasetRef(GDERun);

Use the getElement function with a cell array containing a character vector to return a Simulink.SimulationData.Dataset object in the workspace that corresponds to a Simulink.sdi.Signal object in the Simulation Data Inspector repository. If the element name is unique, the getElement function returns a Dataset object containing one element. If the element name is not unique, the getElement function returns a Dataset object containing all elements with that name. For example, create a Dataset object containing the element named DifName.

ds = get(DSRef,{'DifName'})

ds = 
Simulink.SimulationData.Dataset '' with 1 element

                         Name     BlockPath               
                         _______  _______________________ 
    1  [1x1 Signal]      DifName  GetDatasetElements/Out3

  - Use braces { } to access, modify, or add elements using index.