getpvec

Obtain model parameters and associated uncertainty data

Syntax

params = getpvec(sys)

[params,stdDev] = getpvec(sys)

[___] = getpvec(sys,'free')

Description

params = getpvec(sys) returns the parameters values of the identified model sys.

[params,stdDev] = getpvec(sys) also returns the standard deviation value for the parameters.

[___] = getpvec(sys,'free') returns values for only the free parameters of sys. For idnlarx and idnlhw models, all parameters are treated as free.

Examples

Retrieve Parameter Values from Estimated Model

Load the estimation data.

load iddata1 z1;

Estimate a transfer function model.

sys = tfest(z1,3);

Retrieve the parameter values from the estimated model.

pvec = getpvec(sys);

Retrieve Parameter Values and Standard Deviations from Estimated Model

Load the estimation data.

load iddata2 z2;

Estimate a state-space model.

sys = ssest(z2,3);

Retrieve the model parameters, pvec, and associated standard deviations, pvec_sd, from the estimated model.

[pvec,pvec_sd] = getpvec(sys);

Retrieve Values of Free Parameters from Estimated Model

Load the estimation data.

load iddata2 z2;

Estimate a state-space model.

sys = ssest(z2,3);

Retrieve the values of the free parameters from the estimated model.

pvec = getpvec(sys,'free');

Input Arguments

sys — Identified model

identified model object | array of identified model objects

Identified model, specified as one of the following model objects or an array of such objects.

• idtf

• idss

• idgrey

• idpoly

• idproc

• idnlarx

• idnlhw

• idnlgrey

Output Arguments

params — Parameter values

vector | cell array | []

Parameter values, returned as a vector.

If sys is a model array, then params is a cell array of parameter value vectors corresponding to each model in sys.

params is [] for idnlarx and idnlhw models that have not been estimated.

stdDev — Standard deviation values

vector | cell array | []

Standard deviation values for parameters, returned as a vector.

If sys is a model array, then stdDev is a cell array of standard deviation value vectors corresponding to each model in sys.

If the model covariance information for sys is not available, then stdDev is []. As a result, stdDev is always [] for idnlarx and idnlhw models because these models do not store parameter covariance information.

Version History

Introduced in R2012a