# state space model has error

137 views (last 30 days)
Neel on 27 Nov 2013
Commented: Neel Dalwadi on 29 Sep 2021
my A B C D matrices are:
A =
[ 0, 0, 1.0, 0]
[ 0, 0, 0, 1.0]
[ 0, 0.15502416677813339370370805808099, -4.7863736679940324215607420213982, -0.0000033656243151182583405463328000383]
[ 0, -26.094361926054232600130044495449, -11.022752876224010373586983854075, 0.0000077508459792499219645213236865318]
B =
0
0
0.88636549407296896004815441721882
-2.0412505326340757878851343018816
C =
[ 1.0, 0, 0, 0]
[ 1.0, 0, 1.0, 0]
D =
0
0
when i do sys = ss(A,B,C,D)
Error using ss (line 260) The value of the "a" property must be a numeric array without any Inf's or NaN's.
Error in delete6 (line 50) sys = (ss(A,B,C,D))
this error is seen
how to solve this?

Elias Hasle on 11 Oct 2018
I don't know if this is relevant to your (five year old) case, but in case someone else encounters this error message: I got it after inputting data from a symbolic calculation, although the arrays did not look symbolical. Casting the arguments to double removed the error.
Neel Dalwadi on 29 Sep 2021
You can use the function double() for Matlab.

Osman AKYUREK on 12 Nov 2019
Hi,
I have the same error massage. I think this is because of the fact that some zeros in the matrix A. Therefore, the response of the model cannot be obtained through state-space modelling. You need to check out the matrix A. For example in my case:
if there is zero component in the matrix Mst, the same error pops up, because it is going to be infinitive value in the matrix A. I hope this helps you. Check your matrix A.
Best,
Osman

Azzi Abdelmalek on 27 Nov 2013
Your arrays are not correctly written
A =[ 0, 0, 1.0, 0
0, 0, 0, 1.0
0, 0.15502416677813339370370805808099, -4.7863736679940324215607420213982, -0.0000033656243151182583405463328000383
0, -26.094361926054232600130044495449, -11.022752876224010373586983854075, 0.0000077508459792499219645213236865318]
B =[0;0;0.88636549407296896004815441721882; -2.0412505326340757878851343018816]
C =[ 1.0, 0, 0, 0; 1.0, 0, 1.0, 0]
D =[ 0; 0]
sys = ss(A,B,C,D)

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