Linear time-invariant time response kernel, MATLAB vs Octave Code

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Linear time-invariant time response kernel, MATLAB vs Octave Code

babelproofreader
I am trying to get some MATLAB scripts to run in Octave, but have a problem with the following line of code:

x = ltitr( a, b, u, x0 ) ;

which throws an error in Octave.

Online research shows that the ltitr function is an internal MATLAB function that returns the Linear time-invariant time response kernel for the given inputs. This sounds as if it should be a common DSP requirement, so I feel that this must be implemented directly in Octave, or in the latest Control package from Source Forge. However, I can't seem to find an Octave equivalent. I've read the documentation for the latest Octave Control package and maybe I should be using the functions lsim.m or ss.m or dss.m but I'm not really sure.

Can anyone enlighten me? If it's not implemented in Octave, maybe some online reference to code that I could use to write my own ltitr function?
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Re: Linear time-invariant time response kernel, MATLAB vs Octave Code

Lukas Reichlin-4
On 18.09.2014, at 15:47, babelproofreader <[hidden email]> wrote:

> I am trying to get some MATLAB scripts to run in Octave, but have a problem
> with the following line of code:
>
> x = ltitr( a, b, u, x0 ) ;
>
> which throws an error in Octave.
>
> Online research shows that the ltitr function is an internal MATLAB function
> that returns the Linear time-invariant time response kernel for the given
> inputs. This sounds as if it should be a common DSP requirement, so I feel
> that this must be implemented directly in Octave, or in the latest Control
> package from Source Forge. However, I can't seem to find an Octave
> equivalent. I've read the documentation for the latest Octave Control
> package and maybe I should be using the functions lsim.m or ss.m or dss.m
> but I'm not really sure.
>
> Can anyone enlighten me? If it's not implemented in Octave, maybe some
> online reference to code that I could use to write my own ltitr function?


You could start from something like this:


function x = ltitr (a, b, u, x0)

  x = lsim (ss (a, b, [], [], -1), u, [], x0);

endfunction


Hope this helps,
Lukas


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Re: Linear time-invariant time response kernel, MATLAB vs Octave Code

babelproofreader
Lukas Reichlin-4 wrote
On 18.09.2014, at 15:47, babelproofreader <[hidden email]> wrote:

> I am trying to get some MATLAB scripts to run in Octave, but have a problem
> with the following line of code:
>
> x = ltitr( a, b, u, x0 ) ;
>
> which throws an error in Octave.
>
> Online research shows that the ltitr function is an internal MATLAB function
> that returns the Linear time-invariant time response kernel for the given
> inputs. This sounds as if it should be a common DSP requirement, so I feel
> that this must be implemented directly in Octave, or in the latest Control
> package from Source Forge. However, I can't seem to find an Octave
> equivalent. I've read the documentation for the latest Octave Control
> package and maybe I should be using the functions lsim.m or ss.m or dss.m
> but I'm not really sure.
>
> Can anyone enlighten me? If it's not implemented in Octave, maybe some
> online reference to code that I could use to write my own ltitr function?


You could start from something like this:


function x = ltitr (a, b, u, x0)

  x = lsim (ss (a, b, [], [], -1), u, [], x0);

endfunction


Hope this helps,
Lukas


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Help-octave mailing list
[hidden email]
https://lists.gnu.org/mailman/listinfo/help-octave
This works. Thanks