why polybuffer example doesn't work ?

I'm trying to use the function polybuffer for 2-D points or lines as in example:

https://www.mathworks.com/help/matlab/ref/polybuffer.html

P = [0 0; 1 1; 2 1];
polyout = polybuffer(P,'points',0.25)
plot(P(:,1),P(:,2),'r.','MarkerSize',10)
hold on
plot(polyout)
axis equal

or

 P = [0 0; 1 1; 2 1];
polyout1 = polybuffer(P,'lines',0.25);
plot(P(:,1),P(:,2),'r.','MarkerSize',10)
hold on
plot(polyout1)
axis equal
hold off

but keep getting the following error:

 Undefined function 'polybuffer' for input arguments of type 'double'.

Though the function works fine when using the following example:

https://www.mathworks.com/help/matlab/ref/polyshape.polybuffer.html

 polyin = polyshape({[0 0 1 3],[0.5 1.5 1.5 0.5]},{[0 3 3 0],[0.5 0.5 1.5 1.5]});
 plot(polyin)
 polyout1 = polybuffer(polyin,0.1);
 hold on
 plot(polyout1)
 hold off

does anyone have an idea what did i do wrong ?

Thank you so much

[John D'Errico]

When something does not work because it is not found, the very first question you should ask of yourself is what version of MATLAB you have. polyshape is fairly new as I recall.

If you are using an old release of MATLAb, you could/should look to see if that function was not created until after your release was issued. If not, then what can you expect?

If you have a current release, you might look to see if that code is in a specific toolbox you don't have. But polyshape is in MATLAB proper, at least if you have a current release.

So show the results from the ver command.

[Guillaume]

polyshape requires R2017b or later, but polybuffer is even newer and requires the latest version: R2018a.

[Faez Alkadi]

Hi John,

My matlab is R2017b. And as i said in the question polyshape is working fine with the last example.

i run ver and got the following :

MATLAB                                                Version 9.3         (R2017b)   
Simulink                                              Version 9.0         (R2017b)   
Control System Toolbox                                Version 10.3        (R2017b)   
DSP System Toolbox                                    Version 9.5         (R2017b)   
Data Acquisition Toolbox                              Version 3.12        (R2017b)   
Image Processing Toolbox                              Version 10.1        (R2017b)   
Instrument Control Toolbox                            Version 3.12        (R2017b)   
Mapping Toolbox                                       Version 4.5.1       (R2017b)   
Optimization Toolbox                                  Version 8.0         (R2017b)   
POLYGONS Manipulation of planar polygons and po...    Version 1.6         21-Mar-2011
Signal Processing Toolbox                             Version 7.5         (R2017b)   
Simulink Control Design                               Version 5.0         (R2017b)   
Statistics and Machine Learning Toolbox               Version 11.2        (R2017b)   
Symbolic Math Toolbox                                 Version 8.0         (R2017b)   
>>

Answer 1

[Guillaume]

does anyone have an idea what did i do wrong

Yes, most likely you're not using R2018a, which, for now, is the only version where polybuffer is implemented.

[Faez Alkadi]

Thank you Guillaume, i just updated my matlab to R2018a And it is working now.