why the bode function doesn't work?

this is my problem...

>> s=tf('s')

s =

s

Continuous-time transfer function.

>> g=1/(1+s)

g =

    1
  -----
  s + 1

Continuous-time transfer function.

>> bode(g) Error using DynamicSystem/bode (line 97) Index exceeds matrix dimensions.

can anyone solve it?

Answer 1

[Felix Götze]

Hi,

I had the same Problem. In my case the error occured because I had a figure window open. If you have an open figure close it and try the command again it should work properly now.

Answer 2

[Youssef Khmou]

The description is correct and the code is working correctly,try clearing the existing variables

 clear all;
 s=tf('s'); g=1/(1+s); bode(g);

[jia ming chen]

no, it still doesn't work. i think is a problem of che code or my matlab version... the system says that there is a problem in the line 97 of the code , but I've never touched the source of the code.

[Youssef Khmou]

Bode function contains the following code from line 92 through 100

 92 case 3
93   % Transfer function form with time vector
94   if size(a,1)>1,
95      % SIMO syntax
96      a = num2cell(a,2);
97     den = b;
98      b = cell(size(a,1),1);
99      b(:) = {den};
100   end

Answer 3

[Andreas Goser]

Can you verify the output of

which bode -all

Youe should get something like this:

C:\Program Files\MATLAB\R2014b\toolbox\control\ctrlobsolete\bode.m
C:\Program Files\MATLAB\R2014b\toolbox\shared\controllib\engine\@DynamicSystem\bode.m  % DynamicSystem method

Is not, there maybe another function or variable shadowing the bode function you want.

[Lukas Kurmann]

Hi all,

   as stupid it may sound, I have the same problem - bode is not working (any more). Checked possible shadowing, but it seems not the case... Maybe my path is too long (C:\Projects\FHNW\Vorlesungen\HT FHNW\LF Medizinische Automatisierungssysteme\2015FS\03.Unterrichtsvorbereitung\20150316 WK12 - Block 9 - Diskrete Regler\MATLAB')?
Run currently the 8.3.0.532 (R2014a) version, but shall I update to the R2015a? Thx for an answer! BR Lukas

[Andreas Goser]

This user had a different error message. The solution was a compatibility with a 3rd part toolbox. Once this was removed from the path, BODE was working fine.