Re: [python-control-discuss] really weird error for SISO step response

[Ryan K. <kra...@gv...>]

Good times.  I have updated to 10.14.6.  I have 39GB of free hard drive
space.  But apparently this isn't enough to install xcode..............

--
Dr. Ryan Krauss
Associate Professor
Product Design and Manufacturing Engineering
Grand Valley State University


On Fri, Aug 30, 2019 at 11:27 AM Ryan Krauss <kra...@gv...> wrote:

> I guess I have to upgrade to OSX 10.14 to get xcode back......
>
> This could take a minute.....
>
> --
> Dr. Ryan Krauss
> Associate Professor
> Product Design and Manufacturing Engineering
> Grand Valley State University
>
>
> On Fri, Aug 30, 2019 at 11:26 AM Ryan Krauss <kra...@gv...> wrote:
>
>> I just ran a pip upgrade for the control module.  I am running 0.8.2.
>>
>> I just tried upgrading slycot via pip.  pip says I am currently running
>> 0.3.0.  I tried to upgrade to 0.3.5 via pip, but I receive error messages
>> about gfortran and xcode.  I am kind of surprised that I don't have them
>> both working.  I will work on that.
>>
>> I am getting False for this variable: slycot.__SLYCOT_SETUP__
>>
>> --
>> Dr. Ryan Krauss
>> Associate Professor
>> Product Design and Manufacturing Engineering
>> Grand Valley State University
>>
>>
>> On Fri, Aug 30, 2019 at 2:16 AM Murray, Richard M. <
>> mu...@cd...> wrote:
>>
>>> Which version of python-control and slycot?  I just ran against the
>>> latest master and slycot 0.3.4 and it didn’t generate an error.
>>>
>>> -richard
>>>
>>> > On 29 Aug 2019, at 11:04 , Ryan Krauss <kra...@gv...> wrote:
>>> >
>>> > I am trying to do a super basic step response for a first order TF and
>>> am getting an error I have never seen before.  The notebook is attached,
>>> but here is the code and the error message:
>>> >
>>> > %matplotlib inline
>>> > import matplotlib.pyplot as plt
>>> > import numpy as np
>>> > import control
>>> > from numpy import sin, cos, tan, pi
>>> > from control import TransferFunction as TF
>>> >
>>> > p = 30
>>> >
>>> > G = control.TransferFunction(p,[1,p])
>>> > G
>>> >
>>> > control.step_response(G)
>>> >
>>> >
>>> ---------------------------------------------------------------------------
>>> > ValueError
>>> >                                 Traceback (most recent call last)
>>> >
>>> > <ipython-input-7-7235fbf92fdd> in <module>()
>>> > ----> 1 control.step_response(G)
>>> >
>>> >
>>> >
>>> > /usr/local/lib/python3.6/site-packages/control/timeresp.py in
>>> step_response(sys, T, X0, input, output, transpose, return_x)
>>> >     450     >>> T, yout = step_response(sys, T, X0)
>>> >     451
>>> >      """
>>> >
>>> > --> 452     sys = _get_ss_simo(sys, input, output)
>>> >     453     if T is None:
>>> >     454         if isctime(sys):
>>> >
>>> >
>>> >
>>> > /usr/local/lib/python3.6/site-packages/control/timeresp.py in
>>> _get_ss_simo(sys, input, output)
>>> >     378     If input is not specified, select first input and
>>> >  issue warning
>>> >
>>> >     379
>>> >      """
>>> >
>>> > --> 380     sys_ss = _convertToStateSpace(sys)
>>> >     381     if sys_ss.issiso():
>>> >     382         return
>>> >  sys_ss
>>> >
>>> >
>>> > /usr/local/lib/python3.6/site-packages/control/statesp.py in
>>> _convertToStateSpace(sys, **kw)
>>> >     895             # transfer function to state space conversion now
>>> should work!
>>> >     896
>>> >              ssout = td04ad('C', sys.inputs, sys.outputs,
>>> >
>>> > --> 897
>>> >                             denorder, den, num, tol=0)
>>> >
>>> >     898
>>> >
>>> >
>>> >     899             states = ssout[0]
>>> >
>>> >
>>> >
>>> > /usr/local/lib/python3.6/site-packages/slycot/transform.py in
>>> td04ad(rowcol, m, p, index, dcoeff, ucoeff, tol, ldwork)
>>> >     446         e = ValueError(error_text)
>>> >     447         e.info = out[-1]
>>> > --> 448         raise
>>> >  e
>>> >
>>> >     449     if out[-1] > 0:
>>> >     450         error_text = "The leading coefficient of a denominator
>>> polynomial is nearly zero; calculations would overflow; no state-space
>>> representation was calculated.
>>> ABS(DCOEFF("+str(out[-1])+",1))="+str(abs(dcoeff(out[-1],1)))+" is too
>>> small."
>>> >
>>> >
>>> >
>>> > ValueError: The following argument had an illegal value: dcoeff
>>> >
>>> > --
>>> > Dr. Ryan Krauss
>>> > Associate Professor
>>> > Product Design and Manufacturing Engineering
>>> > Grand Valley State University
>>> > <illegeal_dcoeff.ipynb>_______________________________________________
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>>>
>>>
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>>