anchor.diff:  REAL, DIMENSION(:,:), ALLOCATABLE :: D              ! Diffusion coefficient
   REAL, DIMENSION(:,:), ALLOCATABLE :: sigr           ! Removal macroscopic cx
   
  - 
  +!! CXs Assigned to Materials
  +REAL, DIMENSION(:,:), ALLOCATABLE :: xsigtr          ! Transport macroscopic cx
  +REAL, DIMENSION(:,:), ALLOCATABLE :: xsiga           ! Absorption macroscopic cx
  +REAL, DIMENSION(:,:), ALLOCATABLE :: xnuf            ! nu* fission macroscopic cx
  +REAL, DIMENSION(:,:), ALLOCATABLE :: xsigf           ! fission macroscopic cx
  +REAL, DIMENSION(:,:), ALLOCATABLE :: xchi            ! neutron fission spectrum
  +REAL, DIMENSION(:,:), ALLOCATABLE :: xD              ! Diffusion coefficient
  +REAL, DIMENSION(:,:), ALLOCATABLE :: xsigr           ! Removal macroscopic cx
  +REAL, DIMENSION(:,:,:), ALLOCATABLE :: xsigs         ! Scattering macroscopic cx
  +LOGICAL :: ccnuf = .TRUE.                            ! Logical variable to check the presence of fissile material
  +LOGICAL :: ccsigf = .TRUE.                           ! Logical variable to check the presence of fissile material
  +
  +! Geometry 
   INTEGER :: nx, ny, nz                                ! Number of assemblies in x, y, and z directions
   INTEGER :: nxx, nyy, nzz                             ! Number of nodes in x, y, and z directions 
   INTEGER :: nnod                                      ! Number of nodes
   INTEGER, DIMENSION(:), ALLOCATABLE :: ix, iy, iz
   INTEGER, DIMENSION(:,:,:), ALLOCATABLE :: xyz
  -INTEGER, DIMENSION(:), ALLOCATABLE :: xdiv, ydiv, zdiv  ! Assembly division
  -REAL, DIMENSION(:), ALLOCATABLE :: xdel, ydel, zdel  ! Delta x, y and z
  -INTEGER :: xwest, xeast, ysouth, ynorth, zbott, ztop   ! Boundary conditions
  +INTEGER, DIMENSION(:), ALLOCATABLE :: xdiv, ydiv, zdiv     ! Assembly division
  +REAL, DIMENSION(:), ALLOCATABLE :: xdel, ydel, zdel, vdel  ! Delta x, y and z and nodes' volume in cm3
  +INTEGER :: xwest, xeast, ysouth, ynorth, zbott, ztop       ! Boundary conditions
  +INTEGER, DIMENSION(:), ALLOCATABLE :: mat
   
  +! Keff, flux and currents
   REAL :: Ke
   TYPE :: NODE_DATA
   	REAL, DIMENSION(6) :: jo             ! Nodals' outgoing currents (X+,X-,Y+, Y-, Z+, Z-)
  
positive.code: 
  INTEGER :: ng     ! number of groups
  INTEGER :: nmat   ! number of materials
  ! MAterial CX data
  REAL, DIMENSION(:,:), ALLOCATABLE :: sigtr          ! Transport macroscopic cx
  REAL, DIMENSION(:,:), ALLOCATABLE :: siga           ! Absorption macroscopic cx
  REAL, DIMENSION(:,:), ALLOCATABLE :: nuf            ! nu* fission macroscopic cx
  
negative.code: REAL :: serc = 1.e-5
  REAL :: ierc = 1.e-5
  INTEGER :: nin = 2
  INTEGER :: nout = 500
  INTEGER :: nac = 5
  
  ! OUTPUT PRINT OPTION
  