On Wed, Jul 6, 2011 at 8:29 PM, Lukas Reichlin <[email protected]> wrote: > On 06.07.2011, at 14:54, Juan Pablo Carbajal wrote: > >> Hi Lukas, >> I was following your example of a wrapper and found the following >> the function ss2tf has a different interface than your function ss. >> The last argument is not the time sample as in your function but an >> index of the input vector >> http://www.mathworks.com/help/toolbox/signal/ss2tf.html >> >> Is there any of the options in your ss function that can handle this >> or should that option be added? >> >> Also, I cannot access tfdata directly nor octave can find it (though >> is there in @lti), I am not experienced with objects and may be >> something related to that. > > Matlab's Signal Toolbox looks like a dump for old Control System Toolbox > commands ;-) > > Systems are handled like matrices: > > matrix(row_indices, column_indices) > system(output_indices, input_indices) > > To select only certain inputs: > sys(:, idx) > > Regards > Lukas > > > >
Lukas, thanks for the answer If one is searching for the transfer function for the iu-th input it is needed to be able to access the matrices in the state space representation, not only inputs and outputs. Therefore I do not think sys(:,idx) would help. In the old package (1995, this is not even the legacy you passed me) ss2tf has a loop over k (the number of outputs) and calculates the numerator of the TF as num(k,:) = poly(a - b(:,iu)*c(k,:)) - poly(a) + d(k,iu)*den; where a,b,c,d are the system SS matrices. I think this should be added to your example right? or you see a workaround? Cheers, JPi -- M. Sc. Juan Pablo Carbajal ----- PhD Student University of Zürich www.ailab.ch/carbajal ------------------------------------------------------------------------------ All of the data generated in your IT infrastructure is seriously valuable. Why? It contains a definitive record of application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-d2d-c2 _______________________________________________ Octave-dev mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/octave-dev
