Type mshel (mshel%realvolume )

mshel%xxx is the type that defines the element information of the mesh read in from gmsh file. The element includes 1. Point 2. Line 3. Surface 4. Volume.

  mshel%n        ! total element numbers, including point, line, surface, and volume
  mshel%tetraelenum   ! Total tetrahedron element number
  mshel%tetraelenumstart    ! The starting point of the tetrahedron element number
  mshel%realvolnum(i)     ! Indicating what the volume number the element belongs to
  mshel%nlold(4,i)     ! The orginal node number of the tetrahydron number (gmsh number)
  mshel%nl(4,i)       ! The 4 node numbers of the tetrahydron  (The node number may change after applying the periodic boundary condition)