How to set a vector as initial condition for PDEs?

I'm trying to set a vector, Cini, containing a spatially-varying quantity as my intial codition in a pde for all except the first instance of a loop (in this instance, initial condition is uniform for r<=R1). In the current wrong syntax (below), it's tripping the code up. How do I go about correctly implementing this?

function c0 = pdex2ic(r)
if r <= R1
    if i==1
        c0 = C0;
    else
        c0 = Cini;
    end 
else
    c0 = 0;
end
end

Answer 1

[Torsten]

Generate two data vectors R and C0 where R covers the complete spatial interval of integration.

Then

function c0 = pdex2ic(r,R,C0)
  c0 = interp1(R,C0,r)
end

Note that you will have to pass pdex2ic as @(r)pdex2ic(r,R,C0) to the integrator.