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_remove_useless_states() can change types to ndarrays #82
Description
It seems that if you enter the if statement here then it replaces self.A withself.A with zeros(1,1) which is of type ndarray. This will cause problems later as the library is taking advantage of the fact that * is matrix multiplication not elementwise multiplcation as it would be for ndarrays.
Here is an example of the problem
sys1 = control.StateSpace(0,0,0,0)
sys2 = control.StateSpace(1,0,0,0)
print "type(sys1.A)", type(sys1.A)
print "type(sys2.A)", type(sys2.A)
type(sys1.A) <type 'numpy.ndarray'>
type(sys2.A) <class 'numpy.matrixlib.defmatrix.matrix'>
Activity
roryyorke commentedon Aug 12, 2016
Fixed in #107 (and it's follow-on, #108); above sample now gives
slivingston commentedon Aug 14, 2016
The link to the source code given in the opening post is floating (i.e., it tracks the tip of master branch). For posterity, a link that is fixed with respect to the current master is
python-control/control/statesp.py
Lines 182 to 186 in 58a3ff2
roryyorke commentedon Jan 1, 2017
Bug not present in d8b07cb; most likely fixed by #110, which superseded #107 and #108.
slivingston commentedon Jan 1, 2017
Yes, I agree that it is fixed. I just ran the example from the opening post using the current tip of
masterbranch (32f13bc), and the output isas reported earlier in #82 (comment).