PDE thermal model with heat produced as a function of temperature

For the steady state heat transfer model I want to specify internal heat source as a function of local temperature. I tried as:

internalHeatSource(myPde, @(location, state) k*state.u, 'cell', 1);

but when I solve the model, I get an error:

Dot indexing is not supported for variables of this type.

Can you explain me how to properly do that?

Answer 1

[Urban Simoncic]

Documentation says: "The state data is a structure array with the fields state.u, state.ux, state.uy, state.uz (for 3-D problems), and state.time (for transient problems). The state.u field contains the solution vector. The state.ux, state.uy, state.uz fields are estimates of the solution’s partial derivatives at the corresponding points of the location structure. The state.time field contains time at evaluation points."

When I try to write function handle for internal heat source and print out 'state' variable, it shows that the 'state' is empty. That must be the reason why I can't get 'state.u'.