  Finite-time coherent sets inhibit mixing over finite times. The most
expensive part of the transfer operator approach to detecting coherent sets is
the construction of the operator itself. We present a numerical method based on
radial basis function collocation and apply it to a recent transfer operator
construction that has been designed specifically for purely advective dynamics.
The construction is based on a "dynamic" Laplacian operator and minimises the
boundary size of the coherent sets relative to their volume. The main advantage
of our new approach is a substantial reduction in the number of Lagrangian
trajectories that need to be computed, leading to large speedups in the
transfer operator analysis when this computation is costly.
