sidCompare¶

Python equivalent: sid.compare

Compare model predicted output to measured data.

result = sidCompare(model, y, u)
result = sidCompare(model, y, u, 'InitialState', x0)
sidCompare(model, y, u, 'Plot', true)

Simulates the model's predicted output given the input signal and compares it to the measured output using the NRMSE fit metric.

Inputs¶

Name	Description
`model`	Result struct from any sid estimator (see sidResultTypes). Freq-domain (§1): requires .Response, .Frequency, .SampleTime State-space (§4/§5): requires .A, .B, .StateDim, .InputDim, .DataLength
`y`	(N x ny) measured output, or (N+1 x p x L) state data for COSMIC
`u`	(N x nu) input, or (N x q x L) for multi-trajectory COSMIC

Name	Description
`'InitialState'`	(p x 1) initial state for state-space simulation (default: first row of y)
`'Plot'`	Display comparison plot (default: true if nargout==0)

Name	Description
`result.Predicted`	(N x ny) model-predicted output
`result.Measured`	(N x ny) measured output (copy)
`result.Fit`	(1 x ny) NRMSE fit percentage per channel
`result.Residual`	(N x ny) residual (y - y_pred)
`result.Method`	char, method of the source model

% Compare frequency-domain model to data
G = sidFreqBT(y, u);
result = sidCompare(G, y, u);

% Visual comparison with plot
sidCompare(G, y, u, 'Plot', true);

fit = 100 * (1 - ||y - y_pred|| / ||y - mean(y)||) 100% = perfect, 0% = no better than mean, negative = worse than mean.

(Model output comparison — not yet in SPEC.md)