program main

!*****************************************************************************80
!
!! halton_test() tests halton().
!
!  Licensing:
!
!    This code is distributed under the MIT license.
!
!  Modified:
!
!    11 August 2016
!
!  Author:
!
!    John Burkardt
!
  implicit none

  call timestamp ( )
  write ( *, '(a)' ) ''
  write ( *, '(a)' ) 'halton_test():'
  write ( *, '(a)' ) '  FORTRAN90 version'
  write ( *, '(a)' ) '  Test halton()'

  call halton_test ( )
  call halton_sequence_test ( )
  call halton_inverse_test ( )
  call halton_base_test ( )
!
!  Terminate.
!
  write ( *, '(a)' ) ''
  write ( *, '(a)' ) 'halton_test():'
  write ( *, '(a)' ) '  Normal end of execution.'
  write ( *, '(a)' ) ''
  call timestamp ( )

  stop 0
end
subroutine halton_test ( )

!*****************************************************************************80
!
!! halton_test() tests halton().
!
!  Licensing:
!
!    This code is distributed under the MIT license.
!
!  Modified:
!
!    11 August 2016
!
!  Author:
!
!    John Burkardt
!
  implicit none

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

  integer i
  integer m
  real ( kind = rk ) r(3)

  write ( *, '(a)' ) ''
  write ( *, '(a)' ) 'HALTON_TEST'
  write ( *, '(a)' ) '  HALTON returns the I-th element of an M-dimensional'
  write ( *, '(a)' ) '  Halton sequence.'
  write ( *, '(a)' ) ''
  write ( *, '(a)' ) '    I          HALTON(I)'

  do m = 1, 3
    write ( *, '(a)' ) ''
    write ( *, '(a,i2)' ) '  Use M = ', m
    write ( *, '(a)' ) ''
    do i = 0, 10
      call  halton ( i, m, r )
      write ( *, '(2x,i3,3(2x,f14.8))' ) i, r(1:m)
    end do
  end do

  return
end
subroutine halton_base_test ( )

!*****************************************************************************80
!
!! halton_base_test() tests halton_base().
!
!  Licensing:
!
!    This code is distributed under the MIT license.
!
!  Modified:
!
!    11 August 2016
!
!  Author:
!
!    John Burkardt
!
  implicit none

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

  integer b(3)
  integer i
  integer m
  real ( kind = rk ) r(3)

  write ( *, '(a)' ) ''
  write ( *, '(a)' ) 'HALTON_BASE_TEST'
  write ( *, '(a)' ) '  HALTON_BASE returns the I-th element of an M-dimensional'
  write ( *, '(a)' ) '  Halton sequence, using user-specified bases.'

  m = 3
  b = (/ 2, 3, 5 /)
  write ( *, '(a)' ) ''
  write ( *, '(a,i3)' ) '  M = ', m
  write ( *, '(a,3(2x,i14))' ) '   B:', b(1:m)
  do i = 0, 10
    call  halton_base ( i, m, b, r )
    write ( *, '(2x,i3,3(2x,f14.8))' ) i, r(1:m)
  end do

  m = 3
  b = (/ 3, 10, 2 /)
  write ( *, '(a)' ) ''
  write ( *, '(a,i3)' ) '  M = ', m
  write ( *, '(a,3(2x,i14))' ) '   B:', b(1:m)
  do i = 0, 10
    call  halton_base ( i, m, b, r )
    write ( *, '(2x,i3,3(2x,f14.8))' ) i, r(1:m)
  end do

  return
end
subroutine halton_inverse_test ( )

!*****************************************************************************80
!
!! halton_inverse_test() tests halton_inverse().
!
!  Licensing:
!
!    This code is distributed under the MIT license.
!
!  Modified:
!
!    11 August 2016
!
!  Author:
!
!    John Burkardt
!
  implicit none

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

  integer i
  integer i2
  integer m
  real ( kind = rk ) r(3)

  write ( *, '(a)' ) ''
  write ( *, '(a)' ) 'HALTON_INVERSE_TEST'
  write ( *, '(a)' ) '  HALTON_INVERSE inverts an element of a Halton sequence.'
  write ( *, '(a)' ) ''
  write ( *, '(a)' ) '    I        R=HALTON(I,3)  HALTON_INVERSE(R,3)'
  write ( *, '(a)' ) ''

  m = 3

  do i = 0, 10
    call halton ( i, m, r )
    call halton_inverse ( r, m, i2 )
    write ( *, '(2x,i3,3(2x,f14.8),2x,i3)' ) i, r(1:m), i2
  end do

  return
end
subroutine halton_sequence_test ( )

!*****************************************************************************80
!
!! halton_sequence_test() tests halton_sequence().
!
!  Licensing:
!
!    This code is distributed under the MIT license.
!
!  Modified:
!
!    11 August 2016
!
!  Author:
!
!    John Burkardt
!
  implicit none

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

  integer m
  real ( kind = rk ) r(3,11)

  write ( *, '(a)' ) ''
  write ( *, '(a)' ) 'halton_sequence_test():'
  write ( *, '(a)' ) '  halton_sequence() returns the elements I1 through I2'
  write ( *, '(a)' ) '  of an M-dimensional Halton sequence.'

  do m = 1, 3
    write ( *, '(a)' ) ''
    write ( *, '(a,i1,a)' ) '  HALTON_SEQUENCE(0,10,', m, ',R):'
    call halton_sequence ( 0, 10, m, r )
    call r8mat_print ( m, 11, r, '  R:' )
  end do

  m = 3
  write ( *, '(a)' ) ''
  write ( *, '(a,i1,a)' ) '  HALTON_SEQUENCE(10,0,', m, ',R):'
  call halton_sequence ( 10, 0, m, r )
  call r8mat_print ( m, 11, r, '  R:' )

  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
!
  implicit none

  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 ( *, '(i2,1x,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