[SciPy-user] signal.lti

[Travis Oliphant]

Ryan Krauss wrote:

>I am having a rough time trying to use the lti portion of
>scipy.signal.  For starters, I just wanted to generate a step response
>for an integrator (1/s). 
>
It turns out your starting-point is a special-case not handled by the 
current code (I checked this on old SciPy and it raised errors as 
well).   The current code is "general-purpose" but does not handle 
lonely integrators.  Thus, any time your denominator ends in a zero, you 
will have trouble.  This case needs to be dealt with separately but so 
far isn't (the error could be more informative of course).  You would be 
better of trying a simple first-order system as your starting point.

1/(s+1) 

Which works fine for me with current SciPy.

from pylab import *
from scipy import *

plot(*signal.step((1,[1,1])))





-Travis

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