program main

!*****************************************************************************80
!
!! faure_test() tests faure().
!
!  Licensing:
!
!    This code is distributed under the MIT license.
!
!  Modified:
!
!    04 June 2007
!
!  Author:
!
!    John Burkardt
!
  implicit none

  call timestamp ( )
  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) 'faure_test():'
  write ( *, '(a)' ) '  Fortran90 version'
  write ( *, '(a)' ) '  Test FAURE().'

  call test005 ( )
  call test006 ( )
  call test01 ( )
  call test02 ( )
  call test03 ( )
!
!  Terminate.
!
  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) 'faure_test():'
  write ( *, '(a)' ) '  Normal end of execution.'
  write ( *, '(a)' ) ' '
  call timestamp ( )

  stop 0
end
subroutine test005 ( )

!*****************************************************************************80
!
!! TEST005 tests BINOMIAL_TABLE.
!
!  Licensing:
!
!    This code is distributed under the MIT license.
!
!  Modified:
!
!    08 June 2007
!
!  Author:
!
!    John Burkardt
!
  implicit none

  integer, parameter :: m = 10
  integer, parameter :: n = 7

  integer, dimension ( 0:m, 0:n ) :: coef
  integer i
  integer j
  integer, parameter :: qs = 7

  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) 'TEST005'
  write ( *, '(a)' ) '  BINOMIAL_TABLE computes a table of binomial.'
  write ( *, '(a)' ) '  coefficients mod QS.'
  write ( *, '(a)' ) ' '
  write ( *, '(a,i8)' ) '  Here, QS = ', qs

  call binomial_table ( qs, m, n, coef )

  write ( *, '(a)' ) ' '
  write ( *, '(a,8i8)' ) '   I/J', ( j, j = 0, n )
  write ( *, '(a)' ) ' '

  do i = 0, m
    write ( *, '(2x,i2,2x,8i8)' ) i, coef(i,0:n)
  end do

  return
end
subroutine test006 ( )

!*****************************************************************************80
!
!! TEST006 tests I4_LOG_I4.
!
!  Licensing:
!
!    This code is distributed under the MIT license.
!
!  Modified:
!
!    09 June 2007
!
!  Author:
!
!    John Burkardt
!
  implicit none

  integer i4
  integer i4_log_i4
  integer j4

  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) 'TEST006'
  write ( *, '(a)' ) '  I4_LOG_I4: logarith of I4 base J4,'
  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) '        I4        J4 I4_LOG_I4'
  write ( *, '(a)' ) ' '

  do j4 = 2, 5
    do i4 = 0, 10
      write ( *, '(2x, i8, 2x, i8, 2x, i8 )' ) i4, j4, i4_log_i4 ( i4, j4 )
    end do
    write ( *, '(a)' ) ' '
  end do

  return
end

subroutine test01 ( )

!*****************************************************************************80
!
!! TEST01 tests FAURE.
!
!  Licensing:
!
!    This code is distributed under the MIT license.
!
!  Modified:
!
!    31 January 2007
!
!  Author:
!
!    John Burkardt
!
  implicit none

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

  integer, parameter :: dim_max = 4

  integer dim_num
  integer i
  integer qs
  integer prime_ge
  real ( kind = rk ) r(dim_max)
  integer seed
  integer seed_in
  integer seed_out

  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) 'TEST01'
  write ( *, '(a)' ) '  FAURE computes the next element of a Faure sequence.'
  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) '  In this test, we call FAURE repeatedly.'

  do dim_num = 2, dim_max

    seed = -1
    qs = prime_ge ( dim_num )

    write ( *, '(a)' ) ' '
    write ( *, '(a,i8)' ) '  Using dimension DIM_NUM =   ', dim_num
    write ( *, '(a,i8)' ) '  The prime base QS       =   ', qs
    write ( *, '(a)' ) ' '
    write ( *, '(a)' ) '    Seed    Seed    Faure'
    write ( *, '(a)' ) '      In     Out'
    write ( *, '(a)' ) ' '
    do i = 1, 10
      seed_in = seed
      call faure ( dim_num, seed, r )
      seed_out = seed
      write ( *, '(2i8,4f10.6)' ) seed_in, seed_out, r(1:dim_num)
    end do

  end do

  return
end
subroutine test02 ( )

!*****************************************************************************80
!
!! TEST02 tests FAURE.
!
!  Licensing:
!
!    This code is distributed under the MIT license.
!
!  Modified:
!
!    31 January 2007
!
!  Author:
!
!    John Burkardt
!
  implicit none

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

  integer, parameter :: dim_num = 3

  integer i
  integer qs
  integer prime_ge
  real ( kind = rk ) r(dim_num)
  integer seed
  integer seed_in
  integer seed_out

  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) 'TEST02'
  write ( *, '(a)' ) '  FAURE computes the next element of a Faure sequence.'
  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) '  In this test, we demonstrate how the SEED can be'
  write ( *, '(a)' ) '  manipulated to skip ahead in the sequence, or'
  write ( *, '(a)' ) '  to come back to any part of the sequence.'

  qs = prime_ge ( dim_num )

  write ( *, '(a)' ) ' '
  write ( *, '(a,i8)' ) '  Using dimension DIM_NUM = ', dim_num
  write ( *, '(a,i8)' ) '  The prime base QS       = ', qs

  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) '  Note that on the first call to FAURE, if'
  write ( *, '(a)' ) '  SEED is negative, it is reset to a value that'
  write ( *, '(a)' ) '  is the recommended starting point:'

  seed = -1
  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) '    Seed    Seed    Faure'
  write ( *, '(a)' ) '      In     Out'
  write ( *, '(a)' ) ' '
  do i = 1, 5
    seed_in = seed
    call faure ( dim_num, seed, r )
    seed_out = seed
    write ( *, '(2i8,4f10.6)' ) seed_in, seed_out, r(1:dim_num)
  end do

  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) '  However, if the input value of SEED is 0,'
  write ( *, '(a)' ) '  then no initial skipping is done.'

  seed = 0

  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) '    Seed    Seed    Faure'
  write ( *, '(a)' ) '      In     Out'
  write ( *, '(a)' ) ' '
  do i = 1, 10
    seed_in = seed
    call faure ( dim_num, seed, r )
    seed_out = seed
    write ( *, '(2i8,4f10.6)' ) seed_in, seed_out, r(1:dim_num)
  end do

  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) '  Jump ahead by increasing SEED:'
  write ( *, '(a)' ) ' '

  seed = 100

  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) '    Seed    Seed    Faure'
  write ( *, '(a)' ) '      In     Out'
  write ( *, '(a)' ) ' '
  do i = 1, 5
    seed_in = seed
    call faure ( dim_num, seed, r )
    seed_out = seed
    write ( *, '(2i8,4f10.6)' ) seed_in, seed_out, r(1:dim_num)
  end do

  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) '  Jump back by decreasing SEED:'
  write ( *, '(a)' ) ' '

  seed = 3

  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) '    Seed    Seed    Faure'
  write ( *, '(a)' ) '      In     Out'
  write ( *, '(a)' ) ' '
  do i = 1, 10
    seed_in = seed
    call faure ( dim_num, seed, r )
    seed_out = seed
    write ( *, '(2i8,4f10.6)' ) seed_in, seed_out, r(1:dim_num)
  end do

  return
end
subroutine test03 ( )

!*****************************************************************************80
!
!! TEST03 tests FAURE.
!
!  Licensing:
!
!    This code is distributed under the MIT license.
!
!  Modified:
!
!    04 June 2007
!
!  Author:
!
!    John Burkardt
!
  implicit none

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

  integer, parameter :: dim_base = 10
  integer dim_num
  integer i
  integer qs
  integer prime_ge
  real ( kind = rk ), allocatable, dimension ( : ) :: r
  integer seed
  integer seed_in
  integer seed_out

  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) 'TEST03'
  write ( *, '(a)' ) '  FAURE computes the next element of a Faure sequence.'
  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) '  In this test, we try some large dimensions.'

  do dim_num = dim_base, 6 * dim_base, dim_base

    allocate ( r(1:dim_num) )

    seed = -1
    qs = prime_ge ( dim_num )

    write ( *, '(a)' ) ' '
    write ( *, '(a,i8)' ) '  Using dimension DIM_NUM = ', dim_num
    write ( *, '(a,i8)' ) '  The prime base QS       = ', qs
    do i = 1, 2
      seed_in = seed
      call faure ( dim_num, seed, r )
      seed_out = seed
      write ( *, '(a)' ) ' '
      write ( *, '(a,i10)' ) '  Seed in =  ', seed_in
      write ( *, '(a,i10)' ) '  Seed out = ', seed_out
      write ( *, '(a,i2,a)' ) '  R(1:', dim_num,') = '
      write ( *, '(5(2x,f10.6))' ) r(1:dim_num)
    end do

    deallocate ( r )

  end do

  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:
!
!    03 September 2021
!
!  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