subroutine build_grid(nNuc,ZNuc,rNuc,nShell,TotAngMomShell,ExpShell,max_ang_mom,min_exponent,max_exponent, & 
                      nGrid,weight,root)

! Compute quadrature grid with numgrid (Radovan Bast)

  use numgrid
  use, intrinsic :: iso_c_binding, only: c_ptr

  implicit none
  include 'parameters.h'

! Input variables

  integer,intent(in)            :: nNuc
  double precision,intent(in)   :: ZNuc(nNuc)
  double precision,intent(in)   :: rNuc(nNuc,ncart)

  integer,intent(in)            :: nShell
  integer,intent(in)            :: TotAngMomShell(maxShell)
  double precision,intent(in)   :: ExpShell(maxShell,maxK)

  integer,intent(in)            :: max_ang_mom(nNuc)
  double precision,intent(in)   :: min_exponent(nNuc,maxL+1)
  double precision,intent(in)   :: max_exponent(nNuc)

  integer,intent(in)            :: nGrid

! Local variables
 
  integer                       :: iNuc
  integer                       :: iG

  double precision              :: radial_precision
  integer                       :: min_num_angular_points
  integer                       :: max_num_angular_points
  integer                       :: num_points

  integer                       :: center_index
  type(c_ptr)                   :: context

! Output variables

  double precision,intent(out)  :: root(ncart,nGrid)
  double precision,intent(out)  :: weight(nGrid)

! Set useful variables

  radial_precision = 1d-12
  min_num_angular_points = 6 ! SG-0
  max_num_angular_points = 170 ! SG-3

!------------------------------------------------------------------------
! Main loop over atoms
!------------------------------------------------------------------------

  iG = 0

  do iNuc=1,nNuc

    context = numgrid_new_atom_grid(radial_precision,       &
                                    min_num_angular_points, &
                                    max_num_angular_points, &
                                    int(ZNuc(iNuc)),        &
                                    max_exponent(iNuc),     &
                                    max_ang_mom(iNuc),      &
                                    min_exponent(iNuc,:)    )

    center_index = iNuc - 1
    num_points = numgrid_get_num_grid_points(context)

    call numgrid_get_grid(context,                 &
                          nNuc,                    &
                          center_index,            &
                          rNuc(:,1),               &
                          rNuc(:,2),               &
                          rNuc(:,3),               &
                          int(ZNuc(:)),            &
                          root(1,iG+1:num_points), &
                          root(3,iG+1:num_points), &
                          root(3,iG+1:num_points), &
                          weight(iG+1:num_points)  )

    iG = iG + num_points

    call numgrid_free_atom_grid(context)

  end do

!------------------------------------------------------------------------
! End main loop over atoms
!------------------------------------------------------------------------

! Print grid

  write(*,*) ' ***********************'
  write(*,*) ' *** QUADRATURE GRID ***'
  write(*,*) ' ***********************'
  write(*,'(A10,3X,3A15)') 'Grid point','X','Y','Z'
  do iG=1,nGrid
     write(*,'(I10,3X,4F15.10)') iG,weight(iG),root(:,iG)
  end do
  write(*,*)

end subroutine build_grid