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Compare Output with Measured Data

Plot simulated or predicted output and measured data for comparison, compute best fit values

When you identify a model, you can simulate or predict the model response, and compare that response with measured input/output data. This comparison helps you choose among candidate models, and also aids you in validating the identified model you selected. You can plot model response alongside measured output data, while using initial conditions that can be estimated from the data. You can also compute a metric that quantifies how well your model response matches the measured output data.


expand all

compareCompare identified model output and measured output
compareOptionsOption set for compare
goodnessOfFitGoodness of fit between test and reference data for analysis and validation of identified models
predictPredict K-step-ahead model output
predictOptionsOption set for predict
simSimulate response of identified model
simOptionsOption set for sim
initialConditionInitial condition representation for linear time-invariant systems
findstatesEstimate initial states of model
findstatesOptionsOption set for findstates
data2stateMap past data to states of state-space and nonlinear ARX models
idparCreate parameter for initial states and input level estimation


Compare Model Output to Measured Data

Compare Simulated Output with Measured Validation Data

This example shows how to validate an estimated model by comparing the simulated model output with measured data that was not used for the original estimation.

Plot Models in the System Identification App

To create one or more plots of your models, select the corresponding check box in the Model Views area of the System Identification app.

Set Initial Conditions

Estimate Initial Conditions for Simulating Identified Models

Estimate initial conditions for use in simulations executed from the command line, from Simulink®, and from the System Identification app.

Apply Initial Conditions when Simulating Identified Linear Models

This example describes the workflow for obtaining estimated initial conditions (ICs) for a transfer function model and using the ICs when simulating the model. The example also shows how to use ICs when you convert a model from one model type to another.

Reproduce Command Line or System Identification App Simulation Results in Simulink

Resolve differences between simulation results when comparing command-line or System Identification model outputs with Simulink outputs.

Plot Data

Supported Model Plots

Examine available plot types and corresponding supported models.

Compute Model Uncertainty

Compute model parameter uncertainty of linear models.

Toolbox Preferences Editor

Set plot preferences that persist from session to session.