Array maximum size limit using cat

Hi, I am running a model of diffusion between a source and a sink.

When I change the rate of consumption at the sink, I get this error:

Error using cat
Requested 12326x7x12446 (8.0GB) array exceeds maximum array size preference. Creation of arrays greater than this limit may take a
long time and cause MATLAB to become unresponsive. See array size limit or preference panel for more information.

Error in ode15s (line 845)
      dif3d = cat(3,dif3d, zeros(neq,maxk+2,chunk));

Error in pde.EquationModel/solveTimeDependent (line 104)
sol=ode15s(fcn,tlist,uu0,odeoptions);

Error in pde.PDEModel/solvepde (line 54)
    [u,dudt] = self.solveTimeDependent(coefstruct, u0, ut0, tlist, ...

Error in heat_equation (line 25)
results = solvepde(model, times);

This error occurs if i increase the rate of consumption at the sink too high relative to the rate of production at the source.

I've attached the file, and the file that generates the geometry. Just run heat_equation

Essentially what I am trying to do is model how distance affects diffusion between 2 enzymes. The source rate is a constant, but the the consumption rate is dependent on the concentration of substrate that has diffused - using the Michaelis Menten Equation (myufunction in the file)

Increasing the variable vmax2 causes this error.

Thanks

[Stephen23]

@Alexpluto: what is your question? You forgot to actually ask us something.

That error message seems quite clear: you are asking MATLAB to create a bigger matrix than your computer memory can hold. Clearly that is not going to work.