How to extract idpoly property to workspace

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demos serghiou 2022-12-31

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1886757-how-to-extract-idpoly-property-to-workspace

回答： Star Strider 2022-12-31

采纳的回答： Star Strider

idpoly.mat

Hi, how can I extract and put in my workspace variable A and NoiseVariance from idpoly to do further processing?

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Answer 1

Star Strider 2022-12-31

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https://ww2.mathworks.cn/matlabcentral/answers/1886757-how-to-extract-idpoly-property-to-workspace#answer_1139032

在 MATLAB Online 中打开

There are several properties that can be retrieved from the System Identification Toolbox ‘data’ objects. See the documentation on idpoly and others for details.

Try something like this —

LD = load(websave('idpoly','https://www.mathworks.com/matlabcentral/answers/uploaded_files/1248207/idpoly.mat'))
LD = struct with fields:
    a: [1×0 idpoly]
a = LD.a
a =
Discrete-time AR model: A(z)y(t) = e(t)                                                                                                                                  
                                                                                                                                                                         
  A(z) = 1 + (-7.954 - 0.3i) z^-1 + (26.36 + 2.3i) z^-2 + (-45.35 - 7.6i) z^-3 + (38.88 + 13i) z^-4 + (-7.968 - 12i) z^-5 + (-8.478 + 6.2i) z^-6 + (-3.663 - 2.7i) z^-7  
          + (11.26 + 2.5i) z^-8 + (0.9163 + 0.051i) z^-9 + (-7.189 - 2.7i) z^-10 + (-4.175 + 0.46i) z^-11 + (12.39 + 3.7i) z^-12 + (-4.697 - 5.7i) z^-13 + (-6.017       
              + 3.4i) z^-14 + (6.773 + 3.6i) z^-15 + (-1.439 - 10i) z^-16 + (-1.529 + 11i) z^-17 + (1.173 - 5.9i) z^-18 + (-0.3192 + 1.7i) z^-19 + (0.0307 - 0.21i) z^-20
                                                                                                                                                                         
Sample time: 1 seconds
  
Parameterization:
   Polynomial orders:   na=20
   Number of free coefficients: 20
   Use "polydata", "getpvec", "getcov" for parameters and their uncertainties.

Status:                                                                
Estimated using AR ('burg/now') on time domain data (complex) "est_x1".
Fit to estimation data: 100%                                           
FPE: 2.355e-25, MSE: 2.008e-25                                         
 
Coefficients = a.A
Coefficients = 
   1.0000 + 0.0000i  -7.9541 - 0.2965i  26.3582 + 2.3178i -45.3509 - 7.5709i  38.8797 +13.0764i  -7.9676 -12.3483i  -8.4781 + 6.1760i  -3.6634 - 2.7037i  11.2582 + 2.5171i   0.9163 + 0.0513i  -7.1889 - 2.6674i  -4.1745 + 0.4615i  12.3895 + 3.7428i  -4.6974 - 5.6726i  -6.0167 + 3.4192i   6.7730 + 3.5819i  -1.4387 -10.4534i  -1.5295 +10.7850i   1.1733 - 5.9423i  -0.3192 + 1.7405i   0.0307 - 0.2143i
Variable = a.Variable
Variable = 'z^-1'
Structure = a.Structure
Structure =
                 A: [1×1 param.Continuous]
           IODelay: [1×0 double]
    IntegrateNoise: 0

AR model structure.