Re: Plotting Errors

[James Sherman Jr.]

The output of tf is a struct.

The input of plot is either
plot(x, y) or plot(y) where x and y are matrices of the same size.
(well there are other options, but these are the most basic)

I'm unfamiliar with the the functions to interact with this tf struct,
so I can't help you there.  However, if you just want to plot the
transfer function, i'd do something like:

x = where ever you want to evaluate the function;
y = polyval(num, x)./polyval(den, x);
plot(x, y);

where num is the numerator, den is the denominator (just like in the
tf function).

Hope this helps.

On 10/10/07, Ryan Edwards-Crewe <address@hidden> wrote:
> Hi,
>
> I'm trying to plot the results of this transfer function, but when I do
> I get many errors.
>
> octave:6> gos=tf(1000, [1 2 100], 2);
> octave:7> plot(gos)
> error: mapper: wrong type argument `struct'
> error: evaluating assignment expression near line 47, column 8
> error: called from `__plt1__' in file
> `/usr/share/octave/2.9.9/m/plot/__plt1__.m'
> error: evaluating if command near line 58, column 4
> error: evaluating if command near line 56, column 2
> error: evaluating if command near line 55, column 7
> error: evaluating while command near line 44, column 5
> error: evaluating if command near line 34, column 3
> error: called from `__plt__' in file
> `/usr/share/octave/2.9.9/m/plot/__plt__.m'
> error: called from `plot' in file `/usr/share/octave/2.9.9/m/plot/plot.m'
> octave:7>
>
> don't know what any of this means, any help would be appreciated.
>
> - Crewe
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