or a block structured adaptive mesh refinement (AMR),
where the spacing between the grid points is dictated by the resolution requirements of the physical model in different regions
of the domain. Note that at the time of writing, the only fully supported AMR grid is the octree based PARAMESH [15],
however, work is underway to support patch based Chombo [6] as an alternative in the near future. The discussion in this
paper is focussed on UG and PARAMESH.