- Notifications
You must be signed in to change notification settings - Fork441
Description
The__str__ method inInputOutputSystem assumes that theninputs,noutputs andnstates have all been set to integers, but the constructors do not guarantee this. For example:
>> sys = ctl.NonlinearIOSystem(lambda t, x, u, params: x)>> print(sys)---------------------------------------------------------------------------TypeError Traceback (most recent call last)<ipython-input-4-85c64df40808> in <module>()----> 1 print(sys)/home/arnold/pythonBox/control_dev/python-control-rabraker/control/iosys.py in __str__(self) 214 """String representation of an input/output system""" 215 str = "System: " + (self.name if self.name else "(none)") + "\n"--> 216 str += "Inputs (%d): " % self.ninputs 217 for key in self.input_index: str += key + ", " 218 str += "\nOutputs (%d): " % self.noutputsTypeError: %d format: a number is required, not NoneTypeI would think that once a system is constructed,__str__() should always succeed. The simplest way to fix this is to replace%d with%s in the format string, so it can acceptNoneType. I can submit a PR and add a regression test if this is the desired fix.
This behavior also means that whennoutputs etc are not set, many of the overload operators give unhelpful errors
>>> sys = ctl.NonlinearIOSystem(lambda t, x, u, params: x)>>> sys2 = sys * sys---------------------------------------------------------------------------TypeError Traceback (most recent call last)<ipython-input-27-ea1505c3dfb9> in <module>()----> 1 sys2 = sys * sys/home/arnold/pythonBox/control_dev/python-control-rabraker/control/iosys.py in __mul__(sys2, sys1) 252 253 # Return the series interconnection between the systems--> 254 newsys = InterconnectedSystem((sys1, sys2)) 255 256 # Set up the connecton map/home/arnold/pythonBox/control_dev/python-control-rabraker/control/iosys.py in __init__(self, syslist, connections, inplist, outlist, inputs, outputs, states, params, dt, name) 949 raise TypeError("System '%s' must define number of inputs, " 950 "outputs, states in order to be connected" %--> 951 sys) 952 953 # Keep track of the offsets into the states, inputs, outputs/home/arnold/pythonBox/control_dev/python-control-rabraker/control/iosys.py in __str__(self) 214 """String representation of an input/output system""" 215 str = "System: " + (self.name if self.name else "(none)") + "\n"--> 216 str += "Inputs (%d): " % self.ninputs 217 for key in self.input_index: str += key + ", " 218 str += "\nOutputs (%d): " % self.noutputsTypeError: %d format: a number is required, not NoneTypeAs something of a side note/question/point for discussion: I'm having a hard time groking whyninputs,noutputs andnstates are allowed to beNone. Is there a downside to makinginputs etc a required rather than optional argument in theNonlinearIOSystem constructor? It seems that might make the class easier to use because then all the operators (__mul__() etc) would always work and not depend on how the user called the constructor.