program main

!*****************************************************************************80
!
!! tetrahedron_grid_test() tests tetrahedron_grid().
!
!  Licensing:
!
!    This code is distributed under the MIT license.
!
!  Modified:
!
!    11 November 2011
!
!  Author:
!
!    John Burkardt
!
  implicit none

  integer, parameter :: rk = kind ( 1.0D+00 )

  call timestamp ( )
  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) 'tetrahedron_grid_test():'
  write ( *, '(a)' ) '  Fortran90 version'
  write ( *, '(a)' ) '  Test tetrahedron_grid().'

  call tetrahedron_grid_test01 ( )
!
!  Terminate.
!
  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) 'TETRAHEDRON_GRID_TEST:'
  write ( *, '(a)' ) '  Normal end of execution.'
  write ( *, '(a)' ) ' '
  call timestamp ( )

  stop 0
end
subroutine tetrahedron_grid_test01 ( )

!*****************************************************************************80
!
!! TETRAHEDRON_GRID_TEST01 tests TETRAHEDRON_GRID.
!
!  Licensing:
!
!    This code is distributed under the MIT license.
!
!  Modified:
!
!    10 November 2011
!
!  Author:
!
!    John Burkardt
!
  implicit none

  integer, parameter :: rk = kind ( 1.0D+00 )

  character ( len = 80 ) filename
  integer n
  integer ng
  real ( kind = rk ) :: t(3,4) = reshape ( (/ &
    0.0D+00, 0.0D+00, 0.0D+00, &
    1.0D+00, 0.0D+00, 0.0D+00, &
    0.0D+00, 1.0D+00, 0.0D+00, &
    0.0D+00, 0.0D+00, 1.0D+00 /), (/ 3, 4 /) )
  real ( kind = rk ), allocatable :: tg(:,:)

  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) 'TEST01:'
  write ( *, '(a)' ) '  TETRAHEDRON_GRID can define a tetrahedral grid'
  write ( *, '(a)' ) '  with N+1 points on a side, based on any tetrahedron.'

  n = 10
  write ( *, '(a,i8)' ) '  N = ', n

  call tetrahedron_grid_count ( n, ng )

  call r8mat_print ( 3, 4, t, '  Tetrahedron vertices:' )

  allocate ( tg(1:3,1:ng) )

  call tetrahedron_grid ( n, t, ng, tg )

  call r83vec_print_part ( ng, tg, 20, '  Part of the grid point array:' )

  filename = 'tetrahedron_grid_test01.xyz'

  call r8mat_write ( filename, 3, ng, tg )

  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) '  Data written to the file "' // trim ( filename ) // '".'

  deallocate ( tg )

  return
end
subroutine timestamp ( )

!*****************************************************************************80
!
!! timestamp() prints the current YMDHMS date as a time stamp.
!
!  Example:
!
!    31 May 2001   9:45:54.872 AM
!
!  Licensing:
!
!    This code is distributed under the MIT license.
!
!  Modified:
!
!    18 May 2013
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    None
!
  implicit none

  integer, parameter :: rk = kind ( 1.0D+00 )

  character ( len = 8 ) ampm
  integer d
  integer h
  integer m
  integer mm
  character ( len = 9 ), parameter, dimension(12) :: month = (/ &
    'January  ', 'February ', 'March    ', 'April    ', &
    'May      ', 'June     ', 'July     ', 'August   ', &
    'September', 'October  ', 'November ', 'December ' /)
  integer n
  integer s
  integer values(8)
  integer y

  call date_and_time ( values = values )

  y = values(1)
  m = values(2)
  d = values(3)
  h = values(5)
  n = values(6)
  s = values(7)
  mm = values(8)

  if ( h < 12 ) then
    ampm = 'AM'
  else if ( h == 12 ) then
    if ( n == 0 .and. s == 0 ) then
      ampm = 'Noon'
    else
      ampm = 'PM'
    end if
  else
    h = h - 12
    if ( h < 12 ) then
      ampm = 'PM'
    else if ( h == 12 ) then
      if ( n == 0 .and. s == 0 ) then
        ampm = 'Midnight'
      else
        ampm = 'AM'
      end if
    end if
  end if

  write ( *, '(i2.2,1x,a,1x,i4,2x,i2,a1,i2.2,a1,i2.2,a1,i3.3,1x,a)' ) &
    d, trim ( month(m) ), y, h, ':', n, ':', s, '.', mm, trim ( ampm )

  return
end