geo_t Derived Type

type, public :: geo_t

Cell metrics for all blocks at once, with the grid index last, exactly like block_grid_t holds the solution. One instance covers every block a rank can own (1:max_blocks), so the arrays are allocated once at startup instead of per block, and device kernels can index them directly by igrid rather than chasing a per-block pointer. The corresponding state components (ps(igrid)%x, %dx, ...) are bounds-remapped views into these arrays, so host code keeps working unchanged.

All of it is device-resident, because the device is what produces it: fill_geometry_device builds every member there. That includes dx, which no kernel reads - it has to live where it is written, and is pulled back only on demand (see sync_geometry_host).

  type geo_t
     !> Cell-center positions
     double precision, dimension(:,:,:,:,:), allocatable  :: x
     !> Cell sizes in length unit
     double precision, dimension(:,:,:,:,:), allocatable  :: ds
     !> Volumes of a cell
     double precision, dimension(:,:,:,:), allocatable    :: dvolume
     !> Areas of cell-face surfaces
     double precision, dimension(:,:,:,:,:), allocatable  :: surfaceC
     !> Cell sizes in coordinate units.  Read on the host alone - by calc_x,
     !> by the collapsed output and by set_B0_grid - never by a kernel.
     double precision, dimension(:,:,:,:,:), allocatable  :: dx
  end type geo_t