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doc inconsistency about return type of lqr - matrix vs array #418
Description
I think the doc about the return type of the lqr function looks inconsistent:
https://python-control.readthedocs.io/en/0.8.1/generated/control.lqr.html
states that K is a 2-d array. But it looks a lot like a matrix actually :)
>>> K, _, _ = control.lqr(np.array([1]), np.array([1]), np.array([1]), np.array([1]))
>>> K
matrix([[2.41421356]])
This is Python 3.6.9, control 0.8.3, Ubuntu 18.04 defaults.
This leads to possibly subtle bugs:
Do you think it may be a good idea to 1) update the doc 2) maybe change from matrix to array output altogether? :)
Activity
murrayrm commentedon Jun 12, 2020
The plan is to shift away from the use of the
np.matrixclass at a future point. This functionality is already in place through the use of theuse_numpy_matrixfunction. In version 0.8.3, thenp.matrixclass is still used for backward compatibility, but you can switch to using arrays through the function callWhen we release version 0.9.0, we will switch to have
np.ndarraybe the default class for all matrices inpython-control.I'll leave this issue open for a bit because I think we generally need to update the documentation to reflect that fact that the return type for functions depends on how you have configured
python-control. I've been collecting up documentation updates, so will include those changes in that PR.update lqr() return type documentation (addresses python-control#418)
Documentation update (#476)