[Scipy-tickets] [SciPy] #651: Bug fixed for scipy.signal.tf2zpk
SciPy
scipy-tickets@scipy....
Wed Apr 30 16:41:28 CDT 2008
#651: Bug fixed for scipy.signal.tf2zpk
----------------------------+-----------------------------------------------
Reporter: bow_der_kleine | Owner: somebody
Type: enhancement | Status: new
Priority: normal | Milestone: 0.7
Component: Other | Version:
Severity: normal | Resolution:
Keywords: |
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Comment (by bow_der_kleine):
For example :
{{{
from scipy.signal import *
b,a = bessel(20, 0.1)
z,p,k = tf2zpk(b,a)
# In this line z == array([], dtype=float64). This is a wrong result.
b2, a2 = zpk2tf(z,p,k)
# Here b2 == array([ 1.09154777e-17]). It should be the same as b from
bessel(20, 0.1). But it is not.
}}}
About the code, which you shown from tf2zpk and normalize, I guest, that
it tries to convert the type of array. But it is not a beautiful code. It
would be better with something like that.
{{{
a = array(a).astype(float32)
b = array(b).astype(float32)
}}}
--
Ticket URL: <http://scipy.org/scipy/scipy/ticket/651#comment:2>
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