[firedrake] Pointwise calculations

Dear Firedrakers, One of our favourite testcases, the Galewsky jet, is annoying in that the initial conditions for one of the variables is expressed as a 1-dimensional integral which must be evaluated numerically. In our Fortran code, we used the Fluidity Python interface to evaluate this function pointwise at the node points of the coordinate field, and were thus able to use Numpy quadrature routines to evaluate the integral. What is the best way to do this in Firedrake? all the best --Colin