Simulink.sdi.constraints.MatchesSignal class

Package: Simulink.sdi.constraints
Superclasses: matlab.unittest.constraints.Constraint

Constraint that compares time series data with tolerances using the Simulation Data Inspector

Description

Use the Simulink.sdi.constraints.MatchesSignal constraint to compare time series data against an expected value as part of a test. You can configure the constraint to use a combination of absolute, relative, and time tolerance values for the comparison. You can also specify additional options to configure the comparison behavior using a Simulink.sdi.constraints.MatchesSignalOptions object or using one or more name-value pair arguments. For more information about how tolerances and alignment options affect comparisons, see How the Simulation Data Inspector Compares Data.

Note

The MatchesSignal constraint uses the Simulation Data Inspector to perform comparisons and requires a license for one of these products:

• Simulink^®

• Signal Processing Toolbox™

• MATLAB^® Coder™

• Fixed-Point Designer™

Creation

Description

MatchesSignal(expVal) creates a constraint that determines whether time series data representing an actual value matches the data specified by the expected value, expVal.

MatchesSignal(expVal,Name,Value) creates a constraint with additional properties specified by one or more Name,Value pair arguments.

Input Arguments

Name-Value Pair Arguments

Specify optional comma-separated pairs of Name,Value arguments. Name is the argument name and Value is the corresponding value. Name must appear inside quotes. You can specify several name and value pair arguments in any order as Name1,Value1,...,NameN,ValueN.

Example: 'IgnoringDataTypes',true

'IgnoringDataTypes' — Constraint behavior when data types do not match

false (default) | true

Configure constraint sensitivity to the actual value having a different data type from the expected value.

• false — The constraint checks whether the expected value and actual value data types match.

• true — The constraint is insensitive to data type mismatches between the expected value and actual value.

Example: 'IgnoringDataTypes',true

'IgnoringSignalsNotAligned' — Constraint behavior when signals do not align

false (default) | true

Configure constraint sensitivity to one or more signals not aligning between the expected value and actual value.

• false — The constraint checks for signals that do not align between the expected value and actual value.

• true — The constraint is insensitive to one or more signals not aligning between the expected value and actual value.

Example: 'IgnoringSignalsNotAligned',true

'IgnoringExtraData' — Constraint behavior when the actual value covers a different time interval from the expected value

false (default) | true

Configure the constraint sensitivity to the actual value containing data outside of the time interval defined by the expected value.

• false — The constraint checks whether the actual value contains data outside the time interval defined by the expected value.

• true — The constraint is insensitive to the actual value containing data outside the time interval defined by the expected value.

Example: 'IgnoringExtraData',true

'AligningBy' — Signal alignment criteria

string array

Alignment criteria for the comparison. When the expected value contains more than one signal, the Simulation Data Inspector comparison algorithm aligns signals for comparison between the expected and actual values. By default, the Simulation Data Inspector aligns by data source, then by block path, then by SID, and then by signal name. For details about the Simulation Data Inspector alignment algorithm, see How the Simulation Data Inspector Compares Data.

Specify alignment criteria as a string array with one or more of these options listed in the order in which you want them considered:

• BlockPath — The path to the source block for the signal.

• SID — Simulink identifier. For more information, see Simulink Identifiers.

• SignalName — The name of the signal.

• DataSource — Path of the variable.

Example: 'AligningBy',["SignalName","BlockPath"] specifies signal alignment by signal name and then by block path.

Properties

Expected — Expected value to use as the baseline for the comparison

time series data | string scalar | character array

Expected value to use as the baseline for the comparison. The data for the expected value must pair data values with time. The data can be in any format supported by the Simulation Data Inspector. The Simulation Data Inspector requires data in a format that associates sample values with time. Supported formats include timeseries, Structure with time, and Dataset.

You can specify the expected value for the constraint using a variable in the workspace that contains the data or by specifying the full path or file name of a file that contains the data, as a string scalar or a character array.

Attributes:

GetAccess	public
SetAccess	immutable

MatchesSignalOptions — Constraint comparison configuration options

Simulink.sdi.constraints.MatchesSignalOptions

Simulink.sdi.constraints.MatchesSignalOptions object that specifies options to configure the comparison for the constraint. By default, the comparison uses the default alignment settings for the Simulation Data Inspector and has strict acceptance criteria, meaning that the comparison does not ignore any checks. You can use the MatchesSignalOptions property to configure how the constraint aligns signals in the expected and actual runs and whether tests using the constraint are sensitive to:

• The actual value having a different data type from the expected value.

• One or more signals not aligning between the expected and actual runs.

• The actual value containing data outside the time interval defined by the expected value.

You can specify the MatchesSignalOptions property for the constraint using individual name-value pair arguments or using the name-value pair 'WithOptions' with a Simulink.sdi.constraints.MatchesSignalOptions object as the value. When you specify the MatchesSignalOptions property using a MatchesSignalOptions object, you can use a single name-value pair to configure all the options for comparisons that use the constraint.

Attributes:

GetAccess	public
SetAccess	immutable

Data Types: Simulink.sdi.constraints.MatchesSignalOptions

AbsTol — Absolute tolerance for comparison

0 (default) | scalar

Absolute tolerance for comparisons using the constraint. For details about how the Simulation Data Inspector uses tolerance values in comparisons, see How the Simulation Data Inspector Compares Data.

Example: 0.1

Example: 2

Attributes:

GetAccess	public
SetAccess	immutable

Data Types: double

RelTol — Relative tolerance for comparison

0 (default) | scalar

Relative tolerance for comparisons using the constraint. For example, specify 0.1 to use a 10% tolerance for the comparison. For details about how the Simulation Data Inspector uses tolerance values in comparisons, see How the Simulation Data Inspector Compares Data.

Example: 0.05

Attributes:

GetAccess	public
SetAccess	immutable

Data Types: double

TimeTol — Time tolerance for comparison

0 (default) | scalar

Time tolerance for comparisons using the constraint, in seconds. For details about how the Simulation Data Inspector uses tolerance values in comparisons, see How the Simulation Data Inspector Compares Data.

Example: 0.001

Attributes:

GetAccess	public
SetAccess	immutable

Data Types: double

Examples

Create Tests for Time Series Comparisons

This example shows how to use the Simulink.sdi.constraints.MatchesSignal constraint to compare time series data using data generated in the workspace. You can use the MatchesSignal constraint to compare data from many sources, including measured test data in a file and logged simulation outputs.

When you use the MatchesSignal constraint, you can specify absolute, relative, and time tolerances to use in the comparison. The MatchesSignal constraint uses the Simulation Data Inspector comparison algorithm, which includes steps for alignment and synchronization. For more information about the algorithm, see How the Simulation Data Inspector Compares Data.

The MatchesSignal constraint uses the Simulation Data Inspector for the time series comparison and requires one of these products:

• Simulink®

• Signal Processing Toolbox™

• MATLAB Coder™

• Fixed-Point Designer™

Create Time Series Data

This example generates workspace data in timeseries format for illustrative purposes only. You can use the MatchesSignal constraint to compare data from other sources, such as simulation outputs or a file containing test data, and the constraint can compare time series data in any format supported by the Simulation Data Inspector.

In this example, the first signal is a timeseries object containing data for a sine wave with the name Wave Data.

time = 0:0.1:20;
sig1vals = sin(2*pi/5*time);
sig1_ts = timeseries(sig1vals,time);
sig1_ts.Name = 'Wave Data';

The second signal is also a sine wave at the same frequency, with a slight attenuation and sampled at a different rate. Because the comparison algorithm for the MatchesSignal constraint includes a synchronization step, comparing these two signals with different time vectors does not always result in a test failure. The second signal is also named Wave Data so the alignment algorithm can pair the signals for comparison.

time2 = 0:0.05:20;
sig2vals = 0.98*sin(2*pi/5*time2);
sig2_ts = timeseries(sig2vals,time2);
sig2_ts.Name = 'Wave Data';

Create a Test Case and Compare the Signals

This example uses an interactive test for illustrative purposes. You can use the MatchesSignal constraint with other types of unit tests in the MATLAB testing framework. For example, to write class-based unit tests, see Write Simple Test Case Using Classes.

Create a TestCase instance for interactive use.

import matlab.unittest.TestCase

testCase = TestCase.forInteractiveUse;

Compare sig1_ts and sig2_ts using the MatchesSignal constraint. Use sig1_ts for the expected value in the instance of the MatchesSignal constraint.

import Simulink.sdi.constraints.MatchesSignal

testCase.verifyThat(sig2_ts,MatchesSignal(sig1_ts));

Verification failed.
    ---------------------
    Framework Diagnostic:
    ---------------------
    MatchesSignal(<Value>) failed.
    --> The following aligned signals did not match:
        
               Name         ActualSignals      ExpectedSignals 
            ___________    _______________    _________________
        
            "Wave Data"    "<Actual>.Data"    "<Expected>.Data"
    
    Comparison results have been saved to:
    --> /tmp/Bdoc20b_1498024_127381/comparisonResults_bc39a908-d8e2-41ea-a615-c8d3b0d09ba6.mldatx
    ------------------
    Stack Information:
    ------------------
    In /tmp/Bdoc20b_1498024_127381/tpb0048a0f/simulink-ex22803619/TestTimeSeriesDataWithTimeToleranceExample.mlx (TestTimeSeriesDataWithTimeToleranceExample) at 14
    In /mathworks/devel/bat/Bdoc20b/build/matlab/toolbox/matlab/codetools/embeddedoutputs/+matlab/+internal/+editor/evaluateRegions.p (evaluateRegions) at 0
    In /mathworks/devel/bat/Bdoc20b/build/matlab/toolbox/matlab/codetools/embeddedoutputs/+matlab/+internal/+editor/EvaluationOutputsService.p (EvaluationOutputsService.evalRegions) at 0
    In /mathworks/devel/bat/Bdoc20b/build/matlab/toolbox/matlab/codetools/+matlab/+internal/+liveeditor/@LiveEditorUtilities/execute.m (execute) at 43
    In /mathworks/devel/bat/Bdoc20b/build/matlab/tools/examples/exampletools/+mwtools/liveCodeToDocbook.m (doRun) at 364
    In /mathworks/devel/bat/Bdoc20b/build/matlab/tools/examples/exampletools/+mwtools/liveCodeToDocbook.m (doRunConvert) at 314
    In /mathworks/devel/bat/Bdoc20b/build/matlab/tools/examples/exampletools/+mwtools/liveCodeToDocbook.m (liveCodeToDocbook) at 143
    In /mathworks/devel/bat/Bdoc20b/build/matlab/tools/build_using_matlab/BML.m (BML) at 13

The diagnostic information shows that the verification failed. When a test fails, the comparison results and original run data are saved in a Simulation Data Inspector session file. Click the link for the MLDATX file to open the session in the Simulation Data Inspector, where you can investigate the data compared by the test and the comparison results. When you inspect the results, you can see the attenuation creates the difference and causes the comparison to fail.

Specify an absolute tolerance of 0.02 for the instance of the MatchesSignal constraint to use in the comparison.

testCase.verifyThat(sig2_ts,MatchesSignal(sig1_ts,'AbsTol',0.02));

Verification passed.

Configure MatchesSignal Constraint Behavior

This example shows how to configure the comparison behavior of a Simulink.sdi.constraints.MatchesSignal constraint using a Simulink.sdi.constraints.MatchesSignalOptions object. You can use a MatchesSignalOptions object to configure multiple comparison properties with a single name-value pair input in the construction of the MatchesSignal instance.

Create Time Series Data

This example creates workspace data to use for illustrative purposes only. You can use the MatchesSignal constraint to compare data from other sources, such as simulation outputs or a file containing test data, and the constraint can compare time series data in any format supported by the Simulation Data Inspector.

In this example, the first signal is a timeseries object with the name Wave Data that contains data for a sine wave.

time = 0:0.1:20;
sig1vals = sin(2*pi/5*time);
sig1_ts = timeseries(sig1vals,time);
sig1_ts.Name = 'Wave Data';

The second signal is also a sine wave at the same frequency, with a slight attenuation and sampled at a different rate. Because the comparison algorithm for the MatchesSignal constraint includes a synchronization step, comparing these two signals with different time vectors does not necessarily result in a test failure. The second signal is cast to single data type and also named Wave Data so the alignment algorithm can pair the signals for comparison.

time2 = 0:0.1:22;
sig2vals = single(0.98*sin(2*pi/5*time2));
sig2_ts = timeseries(sig2vals,time2);
sig2_ts.Name = 'Wave Data';

Configure a MatchesSignal Instance and Compare the Data

You can use a MatchesSignalOptions object to specify how an instance of the MatchesSignal constraint handles conditions such as mismatched data types and how signals are aligned between the actual and expected data sets. You can specify the properties of the MatchesSignalOptions object to suit the test you want to write. For example, if you want your test to compare data of varying types and a data type match is not functionally relevant, you could set the IgnoreDataTypes property to true.

Create a MatchesSignalOptions object to create a MatchesSignal instance that ignores data type mismatches and data samples outside the time interval the actual and expected signals share.

import Simulink.sdi.constraints.MatchesSignalOptions
opts = MatchesSignalOptions('IgnoringDataTypes',true,'IgnoringExtraData',true);

Create a TestCase instance for interactive use and compare sig1_ts and sig2_ts using the MatchesSignal constraint, the MatchesSignalOptions object, and an absolute tolerance of 0.02.

import matlab.unittest.TestCase
testCase = TestCase.forInteractiveUse;

import Simulink.sdi.constraints.MatchesSignal
testCase.verifyThat(sig2_ts,MatchesSignal(sig1_ts,'AbsTol',0.02,'WithOptions',opts))

Verification passed.

The test passes. When you run the same test again without the options defined by the MatchesSignalOptions object, the test fails due to the mismatched data types.

testCase.verifyThat(sig2_ts,MatchesSignal(sig1_ts,'AbsTol',0.02))

Verification failed.
    ---------------------
    Framework Diagnostic:
    ---------------------
    MatchesSignal(<Value>,'AbsTol',0.02) failed.
    --> Data types do not match for the following aligned signals:
        
               Name         ActualSignals     ActualDataType     ExpectedSignals     ExpectedDataType
            ___________    _______________    ______________    _________________    ________________
        
            "Wave Data"    "<Actual>.Data"      {'single'}      "<Expected>.Data"       {'double'}   
    
    ------------------
    Stack Information:
    ------------------
    In C:\Users\snadeau\AppData\Local\Temp\Editor_oxzoe\LiveEditorEvaluationHelperE1184446395.m (LiveEditorEvaluationHelperE1184446395) at 16
    In E:\jobarchive\Bdoc20b\2020_06_06_h12m11s21_job1400967_pass\matlab\toolbox\matlab\codetools\embeddedoutputs\+matlab\+internal\+editor\evaluateRegions.p (evaluateRegions) at 0
    In E:\jobarchive\Bdoc20b\2020_06_06_h12m11s21_job1400967_pass\matlab\toolbox\matlab\codetools\embeddedoutputs\+matlab\+internal\+editor\EvaluationOutputsService.p (EvaluationOutputsService.evalRegions) at 0

Compatibility Considerations

Enhanced diagnostic information

Behavior changed in R2020a

Starting in R2020a, when a test that uses the Simulink.sdi.constraints.MatchesSignal constraint fails, the diagnostic information provides a path and link to a Simulation Data Inspector session file that includes the comparison results and the original data compared by the test. Open the session file to inspect the data and comparison results in the Simulation Data Inspector.

In previous releases, the diagnostic information included a path and link to a static image of the comparison results. The diagnostic information no longer includes the image.