Problem constructors and their complete argument documentation are listed on the Public API page.

While choosing to define a PDE using PIDEProblem, note that the function being integrated f is a function of f(x, y, v_x, v_y, ∇v_x, ∇v_y) out of which y is the integrating variable and x is constant throughout the integration. If a PDE has no integral and the non linear term f is just evaluated as f(x, v_x, ∇v_x) then we suggest using ParabolicPDEProblem