Class: Simulink.sdi.DiffRunResult
Package: Simulink.sdi

Return signal comparison result


diffSigObj = diffRunObj.getResultByIndex(index)


diffSigObj = diffRunObj.getResultByIndex(index) returns the Simulink.sdi.DiffSignalResult object diffSigObj corresponding to the index in the Simulink.sdi.DiffRunResult object, diffRunObj.

Input Arguments

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Index of the signal in the Simulink.sdi.DiffRunResult object.

Output Arguments

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Simulink.sdi.DiffSignalResult object for the signal at the specified index.


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You can change tolerance values on a signal-by-signal basis to evaluate the effect of a model parameter change. This example uses the slexAircraftExample model and the Simulation Data Inspector to evaluate the effect of changing the time constant for the low-pass filter following the control input.


Load the model, and mark the q, rad/sec and alpha, rad signals for logging. Then, simulate the model to create the baseline run.

% Load example model

% Mark the q, rad/sec and alpha, rad signals for logging
Simulink.sdi.markSignalForStreaming('slexAircraftExample/Aircraft Dynamics Model',3,'on')
Simulink.sdi.markSignalForStreaming('slexAircraftExample/Aircraft Dynamics Model',4,'on')

% Simulate system
out_1 = sim('slexAircraftExample');

Modify Model Parameter

Modify the model parameter Ts in the model workspace to change the time constant of the input low-pass filter.

% Change input filter time constant
modelWorkspace = get_param('slexAircraftExample','modelworkspace');

% Simulate again
out_2 = sim('slexAircraftExample');

Compare Runs and Inspect Results

Use the Simulink.sdi.compareRuns function to compare the data from the simulations. Then, inspect the match property of the signal result to see whether the signals fell within the default tolerance of 0.

% Get run data
runIDs = Simulink.sdi.getAllRunIDs;
runID1 = runIDs(end - 1);
runID2 = runIDs(end);

% Compare runs
diffRun1 = Simulink.sdi.compareRuns(runID1,runID2);

% Get signal result
sig1Result1 = getResultByIndex(diffRun1,1);
sig2Result1 = getResultByIndex(diffRun1,2);

% Check whether signals matched
ans = 
ans = 

Compare Runs with Signal Tolerances

The signals did not match within the default tolerance of 0. To further analyze the effect of the time constant change, add signal tolerances to the comparison with the baseline signal properties to determine the tolerance required for a pass. This example uses a combination of time and absolute tolerances.

% Get signal object for sigID1
run1 = Simulink.sdi.getRun(runID1);
sigID1 = getSignalIDByIndex(run1,1);
sigID2 = getSignalIDByIndex(run1,2);

sig1 = Simulink.sdi.getSignal(sigID1);
sig2 = Simulink.sdi.getSignal(sigID2);

% Set tolerances for q, rad/sec
sig1.AbsTol = 0.1;
sig1.TimeTol = 0.6;

% Set tolerances for alpha, rad
sig2.AbsTol = 0.2;
sig2.TimeTol = 0.8;

% Run the comparison again
diffRun2 = Simulink.sdi.compareRuns(runID1,runID2);
sig1Result2 = getResultByIndex(diffRun2,1);
sig2Result2 = getResultByIndex(diffRun2,2);

% Check the result
ans = 
ans = 


You can inspect comparison results using the Simulation Data Inspector UI. For more information, see Compare Simulation Data.

Introduced in R2012b