From bug-octave-request at bevo dot che dot wisc dot edu Mon Dec 15 23:10:00 2003
Subject: zp2sys and bode
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: Gabriele Pannocchia <g dot pannocchia at ing dot unipi dot it>
Cc: "Giovanni Visciano" <giovannivisciano at virgilio dot it>,    bug-octave@bevo.che.wisc.edu
Date: Mon, 15 Dec 2003 23:09:47 -0600

On 15-Dec-2003, Gabriele Pannocchia <g dot pannocchia at ing dot unipi dot it> wrote:

| I think the error is generated by line 74 of zp2ss.m.
| Here is my fix proposal.
| 
| --- /usr/share/octave/2.1.50/m/control/system/zp2ss.m	Mon Sep 22 18:06:43 2003
| +++ zp2ss.m	Mon Dec 15 12:43:49 2003
|  at @ -71,7 +71,7 @@
|      warning("zp2ss: k is complex")
|    endif
|  
| -  zpsys = ss2sys([],[],[],k);
| +  zpsys = ss2sys(zeros(0,0),zeros(0,1),zeros(1,0),k);
|  
|    ## Find the number of zeros and the number of poles
|    nzer=length(zer);
| 
| 
| 
| The reason for this fix is that a pure gain system (as it is meant to be
| defined in line 74) should have 0 states but still 1 input and 1 output. Hence
| its state-space matrices should be:
| A = zeros(0,0);
| B = zeros(0,1);
| C = zeros(1,0);
| D = k;

I made this change in CVS.

Thanks,

jwe



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