Bug / compatibility any way to work around?

[RT]

Bug / compatibility problem .  I'm using octave 3.8.1 on ubuntu 14.04 64 bit the code below works in matlab but I get an error when run with octave does anyone know a workaround?

The error that comes back is

error: octave_base_value::array_value(): wrong type argument 'complex matrix'

error: called from: 

which is an error in the set(handle, 'YData', f(x, b)) % set new y-data in plot handle line

Code below:

% // Parameter and x-range

m=3.73;

a=480;

r=1;

fs=44100;

x=linspace(0,2*pi,fs)';

% // function to compute y for given x and parameter b

f = @(x, b) m^3*cos(sqrt(a*r*x)).^(0.77)/r + m^3*cos(sqrt(b*r*x)).^(0.77)/r-20;

% // first plot out of loop (to get plot handle)

figure;

b = 300;

y = f(x, b);

handle = plot(x, y);

xlabel('x') % // only set once

ylabel('y=f(x,b)') % // only set once

title(['b = ' num2str(b)]);

pause(0.1);

% // animate for b = 301 to 86

for b = 301:486 %// Change

set(handle, 'YData', f(x, b)) % set new y-data in plot handle

pause(0.1); %// update plot

title(['b = ' num2str(b)]); %// update title

end