Op:bc
- cartesian_uniform_2d
cartesianfinite_difference
DD2Dxybcgrad_normlimiterreconstructselectorvarcoeff_laplacian
dirichletextrapolate_linearneumannperiodiczero_fluxzero_gradient
Uniform 2-D Cartesian grid with consumer-supplied extent: NX by NY cell-centered points, cell centers (x_i, y_j) = (x0 + (i - 1/2) dx, y0 + (j - 1/2) dy).