Re: rlocus

[Andrei]

In that case, you should specify the returning parameters:
[ro,k_breaks,roots,gains,x_breaks]=rlocus(tf(n,d),0.1,0,10)
and you will get all the roots of the system in variable "roots", with 
their respective gains in vector "gains".
i.e.
roots(:,1)     are from    gain(1)

Eduardo Adam wrote:

> On Thursday 21 June 2007 14:04, Andrei wrote:
>
> Andrei
>  
>
> > ro in your case is the graph, that is plotted.
> > the rlocus function returns multiple roots of the system and graph with
> > different gain (K),
> >    
> This is exactly what I want.  That is, multiple roots for different gain (K) 
> and the comand,
> [ro,Kr]=rlocus(tf(n,d),0.1,0,10)
>
> it doesn't work on my Kubuntu.
>
>
>  
>
> > if you want a specific root, you should use the feedback function for a
> > closed loop, convert the system form to a transfer function and get the
> > roots of the denominator:
> > octave:1> n=1; d=[1 3 2 0];
> > octave:2>[num,den]=feedback(tf(n,d),tf(1,1));
> > octave:3>roots(den)
> > ans =
> >    -2.32472 + 0.0000i
> >    -0.33764 + 0.56228i
> >    -0.33764 - 0.56228i
> >
> > Eduardo Adam wrote:
> >    
> >
> > > Hi everyone,
> > >
> > > I'm sorry for this basic question but I'm a new octave user and, I'm
> > > accustumed to used matlab.  So, I ran the following comands:
> > >
> > > octave:1> n=1; d=[1 3 2 0];
> > > octave:2> [ro,Kr]=rlocus(tf(n,d),0.1,0,10)
> > > warning: in /usr/share/octave/2.1.73/m/control/base/rlocus.m near line 3,
> > > column 8:
> > > warning: rlocus: some elements in list of return values are undefined
> > > ro = [](0x0)
> > > Kr =
> > >
> > > -0.38490
> > >  0.38490
> > >
> > >
> > > My question is, why I have the answer ro=[]?
> > > I'm interested in the closed loop roots and, according to the help, rlocus
> > > would have to provide the roots
> > >
> > > On the other hand, the comand
> > > octave:3> rlocus(tf(n,d),0.1,0,10)
> > >
> > > it works perfectly.
> > > My octave version is 2.1.73 and I'm working with linux-kubuntu.
> > >
> > >
> > > Thanks to everyone.
> > >
> > > Eduardo
> > > _______________________________________________
> > > Help-octave mailing list
> > > address@hidden
> > > https://www.cae.wisc.edu/mailman/listinfo/help-octave
> > >      
>
>