MATLAB: Why polybuffer example doesn’t work

Question

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

Answer 1

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.