Recursive equation

[DannyBoy]

I have this equation, and would like to calculate C(x,t) numerically. The problem I'm having is with the second term on the right hand side, as this means that C(x,t) is effectively defined in terms of itself... Any suggestions?

PS and are simply a decaying exponential and gaussian, respectively, while is the Dirac delta function.

[GiovaMaster]

you ave to create first a vecor of states of C() to know the past of that function, it seams to be an hystory based system