how can I plot heat flux instead of temperature distribution when using the pdeplot() function?

I am currently using:

pdeplot(p, e, t, 'xydata', u(:,end), 'contour', 'on', 'colormap', 'hot')

To plot the temperature distribution of a solution to a pde obtained using parabolic(). How do I instead find plot the heat flux using the pdeplot() command?

Thanks in advance for any help!