; docformat = 'rst'
;+
;This function returns the shape and size of a grid of vectors.
;
; :Examples:
;   dimensions = shape_grid(grid)
;-
;+
; :Params:
;   v : in, required, type=vector of double or grid of vectors
;     A grid of vectors of form v[size_1,size_2,...,size_k,N]. N can be 
;     any positive integer value, but usually is 3 for position vectors 
;     and 4 for quaternions.
;     
; :Returns:
;   A 1D array of integers [size_1,size_2,...,size_k]. This array is 
;   suitable for creating scalar grids directly with 
;   dblarr(shape_grid(...)) or similar, and suitable for creating vector 
;   or quaternion grids with dblarr([shape_grid(...),N]).
;-
function shape_grid,v
  ndims=size(v,/n_dimensions)-1
  return,(size(v,/dimensions))[0:ndims-1]
end