program main

!*****************************************************************************80
!
!! MAIN is the main program for TRIANGULATION_Q2L.
!
!  Discussion:
!
!    TRIANGULATION_Q2L makes a linear triangulation from a quadratic one.
!
!    A quadratic triangulation is assumed to consist of 6-node triangles,
!    as in the following:
!
!    11-12-13-14-15
!     |\    |\    |
!     | \   | \   |
!     6  7  8  9 10
!     |   \ |   \ |
!     |    \|    \|
!     1--2--3--4--5
!
!    This routine rearranges information so as to define the 3-node
!    triangulation:
!
!    11-12-13-14-15
!     |\ |\ |\ |\ |
!     | \| \| \| \|
!     6--7--8--9-10
!     |\ |\ |\ |\ |
!     | \| \| \| \|
!     1--2--3--4--5
!
!  Modified:
!
!    22 March 2005
!
!  Author:
!
!    John Burkardt
!
!  Usage:
!
!    triangulation_q2l triangle_file
!
  implicit none

  integer arg_num
  integer boundary_num
  integer edge_num
  integer i
  integer i4_wrap
  integer iarg
  integer iargc
  integer :: ierror = 0
  integer ii
  character ( len = 256 ) :: input_triangulation_filename = ' '
  integer interior_num
  integer ip1
  integer k1
  integer k2
  integer m
  character ( len = 256 ) :: output_triangulation_filename = ' '
  integer, allocatable, dimension ( :, : ) :: triangle_node1
  integer, allocatable, dimension ( :, : ) :: triangle_node2
  integer triangle_num1
  integer triangle_num2
  integer triangle_order1
  integer triangle_order2

  call timestamp ( )

  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) 'TRIANGULATION_Q2L'
  write ( *, '(a)' ) '  (FORTRAN90 version)'
  write ( *, '(a)' ) '  Read a "quadratic" triangulation and'
  write ( *, '(a)' ) '  write out a "linear" triangulation.'
  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) '  Read a triangulation dataset of TRIANGLE_NUM1'
  write ( *, '(a)' ) '  triangles using 6 nodes.'
  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) '  Create a 3 node triangulation by breaking'
  write ( *, '(a)' ) '  every 6 node triangle into 4 smaller ones.'
  write ( *, '(a)' ) '  Write the new linear triangulation to a file.'
!
!  Get the number of command line arguments.
!
  arg_num = iargc ( )
!
!  If at least one command line argument, it is the triangulation file.
!
  if ( 1 <= arg_num ) then

    iarg = 1
    call getarg ( iarg, input_triangulation_filename )

  else

    write ( *, '(a)' ) ' '
    write ( *, '(a)' ) 'TRIANGULATION_Q2L:'
    write ( *, '(a)' ) '  Please enter the name of the triangulation file.'

    read ( *, '(a)' ) input_triangulation_filename

  end if
!
!  Read the data.
!
  call itable_header_read ( input_triangulation_filename, triangle_order1, &
    triangle_num1 )

  if ( triangle_order1 /= 6 ) then
    write ( *, * ) ' '
    write ( *, '(a)' ) 'TRIANGULATION_Q2L - Fatal error!'
    write ( *, '(a)' ) '  Input data is not for a 6-node triangulation.'
    stop
  end if

  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) '  Read the header of "' &
    // trim ( input_triangulation_filename ) //'".'
  write ( *, '(a)' ) ' '
  write ( *, '(a,i8)' ) '  Triangle order = ', triangle_order1
  write ( *, '(a,i8)' ) '  Number of triangles TRIANGLE_NUM1  = ', triangle_num1

  allocate ( triangle_node1(1:triangle_order1,1:triangle_num1) )

  call itable_data_read ( input_triangulation_filename, triangle_order1, &
    triangle_num1, triangle_node1 )

  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) '  Read the data in "' &
    // trim ( input_triangulation_filename ) //'".'

  call i4mat_transpose_print_some ( triangle_order1, triangle_num1, &
    triangle_node1, &
    1, 1, 6, 10, '  6 by 10 portion TRIANGLE_NODE1:' )
!
!  Create the output file name from the input file name.
!
  output_triangulation_filename = input_triangulation_filename
  call file_name_ext_swap ( output_triangulation_filename, 'q2l.txt' )
!
!  Set the number of linear triangles:
!
  triangle_num2 = 4 * triangle_num1
  triangle_order2 = 3
!
!  Allocate space.
!
  allocate ( triangle_node2(1:triangle_order2,1:triangle_num2) )
!
!  Convert the data.
!
  call triangulation_order6_to_order3 ( triangle_num1, triangle_node1, &
    triangle_num2, triangle_node2 )

  call i4mat_transpose_print ( triangle_order2, triangle_num2, &
    triangle_node2, '  TRIANGLE_NODE2' )
!
!  Write out the node and triangle data for the quadratic mesh
!
  call itable_write ( output_triangulation_filename, triangle_order2, &
    triangle_num2, triangle_node2 )
!
!  Free up memory.
!
  deallocate ( triangle_node1 )
  deallocate ( triangle_node2 )

  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) 'TRIANGULATION_Q2L'
  write ( *, '(a)' ) '  Normal end of execution.'

  write ( *, '(a)' ) ' '
  call timestamp ( )

  stop
end
subroutine ch_cap ( c )

!*****************************************************************************80
!
!! CH_CAP capitalizes a single character.
!
!  Modified:
!
!    19 July 1998
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input/output, character C, the character to capitalize.
!
  implicit none

  character c
  integer itemp

  itemp = ichar ( c )

  if ( 97 <= itemp .and. itemp <= 122 ) then
    c = char ( itemp - 32 )
  end if

  return
end
function ch_eqi ( c1, c2 )

!*****************************************************************************80
!
!! CH_EQI is a case insensitive comparison of two characters for equality.
!
!  Examples:
!
!    CH_EQI ( 'A', 'a' ) is .TRUE.
!
!  Modified:
!
!    28 July 2000
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input, character C1, C2, the characters to compare.
!
!    Output, logical CH_EQI, the result of the comparison.
!
  implicit none

  logical ch_eqi
  character c1
  character c1_cap
  character c2
  character c2_cap

  c1_cap = c1
  c2_cap = c2

  call ch_cap ( c1_cap )
  call ch_cap ( c2_cap )

  if ( c1_cap == c2_cap ) then
    ch_eqi = .true.
  else
    ch_eqi = .false.
  end if

  return
end
subroutine ch_to_digit ( c, digit )

!*****************************************************************************80
!
!! CH_TO_DIGIT returns the integer value of a base 10 digit.
!
!  Example:
!
!     C   DIGIT
!    ---  -----
!    '0'    0
!    '1'    1
!    ...  ...
!    '9'    9
!    ' '    0
!    'X'   -1
!
!  Modified:
!
!    04 August 1999
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input, character C, the decimal digit, '0' through '9' or blank
!    are legal.
!
!    Output, integer DIGIT, the corresponding integer value.  If C was
!    'illegal', then DIGIT is -1.
!
  implicit none

  character c
  integer digit

  if ( lge ( c, '0' ) .and. lle ( c, '9' ) ) then

    digit = ichar ( c ) - 48

  else if ( c == ' ' ) then

    digit = 0

  else

    digit = -1

  end if

  return
end
subroutine file_column_count ( input_filename, column_num )

!*****************************************************************************80
!
!! FILE_COLUMN_COUNT counts the number of columns in the first line of a file.
!
!  Discussion:
!
!    The file is assumed to be a simple text file.
!
!    Most lines of the file is presumed to consist of COLUMN_NUM words,
!    separated by spaces.  There may also be some blank lines, and some 
!    comment lines,
!    which have a "#" in column 1.
!
!    The routine tries to find the first non-comment non-blank line and
!    counts the number of words in that line.
!
!    If all lines are blanks or comments, it goes back and tries to analyze
!    a comment line.
!
!  Modified:
!
!    21 June 2001
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input, character ( len = * ) INPUT_FILENAME, the name of the file.
!
!    Output, integer COLUMN_NUM, the number of columns in the file.
!
  implicit none

  integer column_num
  logical got_one
  character ( len = * ) input_filename
  integer input_unit
  integer ios
  character ( len = 256 ) line
!
!  Open the file.
!
  call get_unit ( input_unit )

  open ( unit = input_unit, file = input_filename, status = 'old', &
    form = 'formatted', access = 'sequential', iostat = ios )

  if ( ios /= 0 ) then
    column_num = -1
    write ( *, '(a)' ) ' '
    write ( *, '(a)' ) 'FILE_COLUMN_COUNT - Fatal error!'
    write ( *, '(a)' ) '  Could not open the file:'
    write ( *, '(a)' ) '    ' // trim ( input_filename )
    return
  end if
!
!  Read one line, but skip blank lines and comment lines.
!
  got_one = .false.

  do

    read ( input_unit, '(a)', iostat = ios ) line

    if ( ios /= 0 ) then
      exit
    end if

    if ( len_trim ( line ) == 0 ) then
      cycle
    end if

    if ( line(1:1) == '#' ) then
      cycle
    end if

    got_one = .true.
    exit

  end do

  if ( .not. got_one ) then

    rewind ( input_unit )

    do

      read ( input_unit, '(a)', iostat = ios ) line

      if ( ios /= 0 ) then
        exit
      end if

      if ( len_trim ( line ) == 0 ) then
        cycle
      end if

      got_one = .true.
      exit

    end do

  end if

  close ( unit = input_unit )

  if ( .not. got_one ) then
    write ( *, '(a)' ) ' '
    write ( *, '(a)' ) 'FILE_COLUMN_COUNT - Warning!'
    write ( *, '(a)' ) '  The file does not seem to contain any data.'
    column_num = -1
    return
  end if

  call s_word_count ( line, column_num )

  return
end
subroutine file_name_ext_get ( file_name, i, j )

!*****************************************************************************80
!
!! FILE_NAME_EXT_GET determines the "extension" of a file name.
!
!  Definition:
!
!    The "extension" of a filename is the string of characters
!    that appears after the LAST period in the name.  A file
!    with no period, or with a period as the last character
!    in the name, has a "null" extension.
!
!  Note:
!
!    Blanks are unusual in filenames.  This routine ignores all
!    trailing blanks, but will treat initial or internal blanks
!    as regular characters acceptable in a file name.
!
!  Examples:
!
!    FILE_NAME   I  J
!
!    bob.for     4  7
!    N.B.C.D     6  7
!    Naomi.      6  6
!    Arthur      0  0
!    .com        1  1
!
!  Modified:
!
!    17 July 1998
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input, character ( len = * ) FILE_NAME, a file name to be examined.
!
!    Output, integer I, J, the indices of the first and last characters
!    in the file extension.
!
!    If no period occurs in FILE_NAME, then
!      I = J = 0;
!    Otherwise,
!      I is the position of the LAST period in FILE_NAME, and J is the
!      position of the last nonblank character following the period.
!
  implicit none

  character ( len = * ) file_name
  integer i
  integer j
  integer s_index_last

  i = s_index_last ( file_name, '.' )

  if ( i /= 0 ) then

    j = len_trim ( file_name )

  else

    j = 0

  end if

  return
end
subroutine file_name_ext_swap ( file_name, ext )

!*****************************************************************************80
!
!! FILE_NAME_EXT_SWAP replaces the current "extension" of a file name.
!
!  Definition:
!
!    The "extension" of a filename is the string of characters
!    that appears after the LAST period in the name.  A file
!    with no period, or with a period as the last character
!    in the name, has a "null" extension.
!
!  Examples:
!
!          Input           Output
!    ================     =========
!    FILE_NAME    EXT     FILE_NAME
!
!    bob.for      obj     bob.obj
!    bob.bob.bob  txt     bob.bob.txt
!    bob          yak     bob.yak
!
!  Modified:
!
!    09 August 1999
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input/output, character ( len = * ) FILE_NAME, a file name.
!    On output, the extension of the file has been changed.
!
!    Input, character ( len = * ) EXT, the extension to be used on the output
!    copy of FILE_NAME, replacing the current extension if any.
!
  implicit none

  character ( len = * ) ext
  character ( len = * ) file_name
  integer i
  integer j
  integer len_max
  integer len_name

  len_max = len ( file_name )
  len_name = len_trim ( file_name )

  call file_name_ext_get ( file_name, i, j )

  if ( i == 0 ) then

    if ( len_max < len_name + 1 ) then
      return
    end if

    len_name = len_name + 1
    file_name(len_name:len_name) = '.'
    i = len_name + 1

  else

    i = i + 1
    file_name(i:j) = ' '

  end if

  file_name(i:) = ext

  return
end
subroutine file_row_count ( input_filename, row_num )

!*****************************************************************************80
!
!! FILE_ROW_COUNT counts the number of row records in a file.
!
!  Discussion:
!
!    It does not count lines that are blank, or that begin with a
!    comment symbol '#'.
!
!  Modified:
!
!    06 March 2003
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input, character ( len = * ) INPUT_FILENAME, the name of the input file.
!
!    Output, integer ROW_NUM, the number of rows found.
!
  implicit none

  integer bad_num
  integer comment_num
  integer ierror
  character ( len = * ) input_filename
  integer input_unit
  integer ios
  character ( len = 100 ) line
  integer record_num
  integer row_num

  call get_unit ( input_unit )

  open ( unit = input_unit, file = input_filename, status = 'old', &
    iostat = ios )

  if ( ios /= 0 ) then
    row_num = -1;
    ierror = 1
    write ( *, '(a)' ) ' '
    write ( *, '(a)' ) 'FILE_ROW_COUNT - Fatal error!'
    write ( *, '(a)' ) '  Could not open the input file: ' // &
      trim ( input_filename )
    stop
  end if

  comment_num = 0
  row_num = 0
  record_num = 0
  bad_num = 0

  do

    read ( input_unit, '(a)', iostat = ios ) line

    if ( ios /= 0 ) then
      ierror = record_num
      exit
    end if

    record_num = record_num + 1

    if ( line(1:1) == '#' ) then
      comment_num = comment_num + 1
      cycle
    end if

    if ( len_trim ( line ) == 0 ) then
      comment_num = comment_num + 1
      cycle
    end if

    row_num = row_num + 1

  end do

  close ( unit = input_unit )

  return
end
subroutine get_unit ( iunit )

!*****************************************************************************80
!
!! GET_UNIT returns a free FORTRAN unit number.
!
!  Discussion:
!
!    A "free" FORTRAN unit number is an integer between 1 and 99 which
!    is not currently associated with an I/O device.  A free FORTRAN unit
!    number is needed in order to open a file with the OPEN command.
!
!    If IUNIT = 0, then no free FORTRAN unit could be found, although
!    all 99 units were checked (except for units 5, 6 and 9, which
!    are commonly reserved for console I/O).
!
!    Otherwise, IUNIT is an integer between 1 and 99, representing a
!    free FORTRAN unit.  Note that GET_UNIT assumes that units 5 and 6
!    are special, and will never return those values.
!
!  Modified:
!
!    18 September 2005
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Output, integer IUNIT, the free unit number.
!
  implicit none

  integer i
  integer ios
  integer iunit
  logical lopen

  iunit = 0

  do i = 1, 99

    if ( i /= 5 .and. i /= 6 .and. i /= 9 ) then

      inquire ( unit = i, opened = lopen, iostat = ios )

      if ( ios == 0 ) then
        if ( .not. lopen ) then
          iunit = i
          return
        end if
      end if

    end if

  end do

  return
end
function i4_modp ( i, j )

!*****************************************************************************80
!
!! I4_MODP returns the nonnegative remainder of integer division.
!
!  Formula:
!
!    If
!      NREM = I_MODP ( I, J )
!      NMULT = ( I - NREM ) / J
!    then
!      I = J * NMULT + NREM
!    where NREM is always nonnegative.
!
!  Comments:
!
!    The MOD function computes a result with the same sign as the
!    quantity being divided.  Thus, suppose you had an angle A,
!    and you wanted to ensure that it was between 0 and 360.
!    Then mod(A,360) would do, if A was positive, but if A
!    was negative, your result would be between -360 and 0.
!
!    On the other hand, I4_MODP(A,360) is between 0 and 360, always.
!
!  Examples:
!
!        I     J     MOD  I4_MODP    Factorization
!
!      107    50       7       7    107 =  2 *  50 + 7
!      107   -50       7       7    107 = -2 * -50 + 7
!     -107    50      -7      43   -107 = -3 *  50 + 43
!     -107   -50      -7      43   -107 =  3 * -50 + 43
!
!  Modified:
!
!    02 March 1999
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input, integer I, the number to be divided.
!
!    Input, integer J, the number that divides I.
!
!    Output, integer I4_MODP, the nonnegative remainder when I is
!    divided by J.
!
  implicit none

  integer i
  integer i4_modp
  integer j

  if ( j == 0 ) then
    write ( *, '(a)' ) ' '
    write ( *, '(a)' ) 'I4_MODP - Fatal error!'
    write ( *, '(a,i8)' ) '  I4_MODP ( I, J ) called with J = ', j
    stop
  end if

  i4_modp = mod ( i, j )

  if ( i4_modp < 0 ) then
    i4_modp = i4_modp + abs ( j )
  end if

  return
end
function i4_wrap ( ival, ilo, ihi )

!*****************************************************************************80
!
!! I4_WRAP forces an integer to lie between given limits by wrapping.
!
!  Example:
!
!    ILO = 4, IHI = 8
!
!    I  I4_WRAP
!
!    -2     8
!    -1     4
!     0     5
!     1     6
!     2     7
!     3     8
!     4     4
!     5     5
!     6     6
!     7     7
!     8     8
!     9     4
!    10     5
!    11     6
!    12     7
!    13     8
!    14     4
!
!  Modified:
!
!    15 July 2000
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input, integer IVAL, an integer value.
!
!    Input, integer ILO, IHI, the desired bounds for the integer value.
!
!    Output, integer I4_WRAP, a "wrapped" version of IVAL.
!
  implicit none

  integer i4_modp
  integer i4_wrap
  integer ihi
  integer ilo
  integer ival
  integer wide

  wide = ihi + 1 - ilo

  if ( wide == 0 ) then
    i4_wrap = ilo
  else
    i4_wrap = ilo + i4_modp ( ival - ilo, wide )
  end if

  return
end
subroutine i4mat_transpose_print ( m, n, a, title )

!*****************************************************************************80
!
!! I4MAT_TRANSPOSE_PRINT prints an I4MAT, transposed.
!
!  Modified:
!
!    28 December 2004
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input, integer M, N, the number of rows and columns.
!
!    Input, integer A(M,N), an M by N matrix to be printed.
!
!    Input, character ( len = * ) TITLE, an optional title.
!
  implicit none

  integer m
  integer n

  integer a(m,n)
  character ( len = * ) title

  call i4mat_transpose_print_some ( m, n, a, 1, 1, m, n, title )

  return
end
subroutine i4mat_transpose_print_some ( m, n, a, ilo, jlo, ihi, jhi, title )

!*****************************************************************************80
!
!! I4MAT_TRANSPOSE_PRINT_SOME prints some of the transpose of an I4MAT.
!
!  Modified:
!
!    09 February 2005
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input, integer M, N, the number of rows and columns.
!
!    Input, integer A(M,N), an M by N matrix to be printed.
!
!    Input, integer ILO, JLO, the first row and column to print.
!
!    Input, integer IHI, JHI, the last row and column to print.
!
!    Input, character ( len = * ) TITLE, an optional title.
!
  implicit none

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

  integer a(m,n)
  character ( len = 7 ) ctemp(incx)
  integer i
  integer i2
  integer i2hi
  integer i2lo
  integer ihi
  integer ilo
  integer inc
  integer j
  integer j2hi
  integer j2lo
  integer jhi
  integer jlo
  character ( len = * ) title

  if ( 0 < len_trim ( title ) ) then
    write ( *, '(a)' ) ' '
    write ( *, '(a)' ) trim ( title )
  end if

  do i2lo = max ( ilo, 1 ), min ( ihi, m ), incx

    i2hi = i2lo + incx - 1
    i2hi = min ( i2hi, m )
    i2hi = min ( i2hi, ihi )

    inc = i2hi + 1 - i2lo

    write ( *, '(a)' ) ' '

    do i = i2lo, i2hi
      i2 = i + 1 - i2lo
      write ( ctemp(i2), '(i7)') i
    end do

    write ( *, '(''  Row '',10a7)' ) ctemp(1:inc)
    write ( *, '(a)' ) '  Col'
    write ( *, '(a)' ) ' '

    j2lo = max ( jlo, 1 )
    j2hi = min ( jhi, n )

    do j = j2lo, j2hi

      do i2 = 1, inc

        i = i2lo - 1 + i2

        write ( ctemp(i2), '(i7)' ) a(i,j)

      end do

      write ( *, '(i5,1x,10a7)' ) j, ( ctemp(i), i = 1, inc )

    end do

  end do

  write ( *, '(a)' ) ' '

  return
end
subroutine itable_data_read ( input_filename, m, n, table )

!*****************************************************************************80
!
!! ITABLE_DATA_READ reads data from an integer table file.
!
!  Discussion:
!
!    The file may contain more than N points, but this routine
!    will return after reading N points.
!
!  Modified:
!
!    08 October 2003
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input, character ( len = * ) INPUT_FILENAME, the name of the input file.
!
!    Input, integer M, the spatial dimension.
!
!    Input, integer N, the number of points.  
!
!    Output, integer TABLE(M,N), the table data.
!
  implicit none

  integer m
  integer n

  integer i
  integer ierror
  character ( len = * ) input_filename
  integer input_unit
  integer ios
  character ( len = 255 ) line
  integer table(m,n)
  integer x(m)

  call get_unit ( input_unit )

  open ( unit = input_unit, file = input_filename, status = 'old', &
    iostat = ios )

  if ( ios /= 0 ) then
    ierror = 1
    write ( *, '(a)' ) ' '
    write ( *, '(a)' ) 'ITABLE_DATA_READ - Fatal error!'
    write ( *, '(a)' ) '  Could not open the input file: ' // &
      trim ( input_filename )
    stop
  end if

  i = 0

  do while ( i < n )

    read ( input_unit, '(a)', iostat = ios ) line

    if ( ios /= 0 ) then
      ierror = i
      exit
    end if

    if ( line(1:1) == '#' .or. len_trim ( line ) == 0 ) then
      cycle
    end if

    call s_to_i4vec ( line, m, x, ierror )

    if ( ierror /= 0 ) then
      cycle
    end if

    i = i + 1

    table(1:m,i) = x(1:m)

  end do

  close ( unit = input_unit )

  return
end
subroutine itable_data_write ( output_unit, m, n, table )

!*****************************************************************************80
!
!! ITABLE_DATA_WRITE writes data to an integer table file.
!
!  Discussion:
!
!    This routine writes a single line of output for each point,
!    containing its spatial coordinates.
!
!  Modified:
!
!    02 October 2003
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input, integer OUTPUT_UNIT, the output unit.
!
!    Input, integer M, the spatial dimension.
!
!    Input, integer N, the number of points.
!
!    Input, integer TABLE(M,N), the table data.
!
  implicit none

  integer m
  integer n

  integer output_unit
  integer j
  character ( len = 30 ) string
  integer table(m,n)
!
!  Create the format string.
!
  write ( string, '(a1,i8,a4)' ) '(', m, 'i10)'
  call s_blank_delete ( string )

  do j = 1, n
    write ( output_unit, string ) table(1:m,j)
  end do

  return
end
subroutine itable_header_read ( input_filename, m, n )

!*****************************************************************************80
!
!! ITABLE_HEADER_READ reads the header from an integer table file.
!
!  Modified:
!
!    04 June 2004
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input, character ( len = * ) INPUT_FILENAME, the name of the input file.
!
!    Output, integer M, spatial dimension.
!
!    Output, integer N, the number of points. 
!
  implicit none

  character ( len = * ) input_filename
  integer m
  integer n

  call file_column_count ( input_filename, m )

  if ( m <= 0 ) then
    write ( *, '(a)' ) ' '
    write ( *, '(a)' ) 'ITABLE_HEADER_READ - Fatal error!'
    write ( *, '(a)' ) '  There was some kind of I/O problem while trying'
    write ( *, '(a)' ) '  to count the number of data columns in'
    write ( *, '(a)' ) '  the file "' // trim ( input_filename ) // '".'
    stop
  end if

  call file_row_count ( input_filename, n )

  if ( n <= 0 ) then
    write ( *, '(a)' ) ' '
    write ( *, '(a)' ) 'ITABLE_HEADER_READ - Fatal error!'
    write ( *, '(a)' ) '  There was some kind of I/O problem while trying'
    write ( *, '(a)' ) '  to count the number of data rows in'
    write ( *, '(a)' ) '  the file "' // trim ( input_filename ) // '".'
    stop
  end if

  return
end
subroutine itable_header_write ( output_filename, output_unit, m, n )

!*****************************************************************************80
!
!! ITABLE_HEADER_WRITE writes the header to an integer table file.
!
!  Modified:
!
!    04 June 2004
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input, character ( len = * ) OUTPUT_FILENAME, the output filename.
!
!    Input, integer OUTPUT_UNIT, the output unit.
!
!    Input, integer M, the spatial dimension.
!
!    Input, integer N, the number of points.
!
  implicit none

  integer m
  integer n
  character ( len = * ) output_filename
  integer output_unit
  character ( len = 40 ) string

  call timestring ( string )

  write ( output_unit, '(a)'       ) '#  ' // trim ( output_filename )
  write ( output_unit, '(a)'       ) '#  created by TABLE_IO.F90'
  write ( output_unit, '(a)'       ) '#  at ' // trim ( string )
  write ( output_unit, '(a)'       ) '#'
  write ( output_unit, '(a,i8)'    ) '#  Spatial dimension M = ', m
  write ( output_unit, '(a,i8)'    ) '#  Number of points N = ', n
  write ( output_unit, '(a)'       ) '#'

  return
end
subroutine itable_write ( output_filename, m, n, table )

!*****************************************************************************80
!
!! ITABLE_WRITE writes an integer table file.
!
!  Modified:
!
!    08 October 2003
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input, character ( len = * ) OUTPUT_FILENAME, the output filename.
!
!    Input, integer M, the spatial dimension.
!
!    Input, integer N, the number of points.
!
!    Input, integer TABLE(M,N), the table data.
!
  implicit none

  integer m
  integer n

  integer ios
  character ( len = * ) output_filename
  integer output_unit
  integer table(m,n)

  call get_unit ( output_unit )

  open ( unit = output_unit, file = output_filename, &
    status = 'replace', iostat = ios )

  if ( ios /= 0 ) then
    write ( *, '(a)' ) ' '
    write ( *, '(a)' ) 'ITABLE_WRITE - Fatal error!'
    write ( *, '(a)' ) '  Could not open the output file.'
    stop
  end if

  call itable_header_write ( output_filename, output_unit, m, n )

  call itable_data_write ( output_unit, m, n, table )

  close ( unit = output_unit )

  return
end
subroutine s_blank_delete ( s )

!*****************************************************************************80
!
!! S_BLANK_DELETE removes blanks from a string, left justifying the remainder.
!
!  Comment:
!
!    All TAB characters are also removed.
!
!  Modified:
!
!    26 July 1998
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input/output, character ( len = * ) S, the string to be transformed.
!
  implicit none

  character c
  integer get
  integer put
  integer nchar
  character ( len = * ) s
  character, parameter :: TAB = char ( 9 )

  put = 0
  nchar = len_trim ( s )

  do get = 1, nchar

    c = s(get:get)

    if ( c /= ' ' .and. c /= TAB ) then
      put = put + 1
      s(put:put) = c
    end if

  end do

  s(put+1:nchar) = ' '

  return
end
function s_index_last ( s, sub )

!*****************************************************************************80
!
!! S_INDEX_LAST finds the LAST occurrence of a given substring.
!
!  Discussion:
!
!    It returns the location in the string at which the substring SUB is
!    first found, or 0 if the substring does not occur at all.
!
!    The routine is also trailing blank insensitive.  This is very
!    important for those cases where you have stored information in
!    larger variables.  If S is of length 80, and SUB is of
!    length 80, then if S = 'FRED' and SUB = 'RED', a match would
!    not be reported by the standard FORTRAN INDEX, because it treats
!    both variables as being 80 characters long!  This routine assumes that
!    trailing blanks represent garbage!
!
!    This means that this routine cannot be used to find, say, the last
!    occurrence of a substring 'A ', since it assumes the blank space
!    was not specified by the user, but is, rather, padding by the
!    system.  However, as a special case, this routine can properly handle
!    the case where either S or SUB is all blanks.
!
!  Modified:
!
!    14 April 1999
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input, character ( len = * ) S, the string to be searched.
!
!    Input, character ( len = * ) SUB, the substring to search for.
!
!    Output, integer S_INDEX_LAST.  0 if SUB does not occur in
!    the string.  Otherwise S_INDEX_LAST = I, where S(I:I+LENS-1) = SUB,
!    where LENS is the length of SUB, and is the last place
!    this happens.
!
  implicit none

  integer i
  integer j
  integer llen1
  integer llen2
  character ( len = * ) s
  integer s_index_last
  character ( len = * ) sub

  s_index_last = 0

  llen1 = len_trim ( s )
  llen2 = len_trim ( sub )
!
!  In case S or SUB is blanks, use LEN
!
  if ( llen1 == 0 ) then
    llen1 = len ( s )
  end if

  if ( llen2 == 0 ) then
    llen2 = len ( sub )
  end if

  if ( llen1 < llen2 ) then
    return
  end if

  do j = 1, llen1+1-llen2

    i = llen1 + 2 - llen2 - j

    if ( s(i:i+llen2-1) == sub ) then
      s_index_last = i
      return
    end if

  end do

  return
end
subroutine s_to_i4 ( s, ival, ierror, length )

!*****************************************************************************80
!
!! S_TO_I4 reads an I4 from a string.
!
!  Modified:
!
!    28 June 2000
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input, character ( len = * ) S, a string to be examined.
!
!    Output, integer IVAL, the integer value read from the string.
!    If the string is blank, then IVAL will be returned 0.
!
!    Output, integer IERROR, an error flag.
!    0, no error.
!    1, an error occurred.
!
!    Output, integer LENGTH, the number of characters of S used to make IVAL.
!
  implicit none

  character c
  integer i
  integer ierror
  integer isgn
  integer istate
  integer ival
  integer length
  character ( len = * ) s

  ierror = 0
  istate = 0
  isgn = 1
  ival = 0

  do i = 1, len_trim ( s )

    c = s(i:i)
!
!  Haven't read anything.
!
    if ( istate == 0 ) then

      if ( c == ' ' ) then

      else if ( c == '-' ) then
        istate = 1
        isgn = -1
      else if ( c == '+' ) then
        istate = 1
        isgn = + 1
      else if ( lle ( '0', c ) .and. lle ( c, '9' ) ) then
        istate = 2
        ival = ichar ( c ) - ichar ( '0' )
      else
        ierror = 1
        return
      end if
!
!  Have read the sign, expecting digits.
!
    else if ( istate == 1 ) then

      if ( c == ' ' ) then

      else if ( lle ( '0', c ) .and. lle ( c, '9' ) ) then
        istate = 2
        ival = ichar ( c ) - ichar ( '0' )
      else
        ierror = 1
        return
      end if
!
!  Have read at least one digit, expecting more.
!
    else if ( istate == 2 ) then

      if ( lle ( '0', c ) .and. lle ( c, '9' ) ) then
        ival = 10 * ival + ichar ( c ) - ichar ( '0' )
      else
        ival = isgn * ival
        length = i - 1
        return
      end if

    end if

  end do
!
!  If we read all the characters in the string, see if we're OK.
!
  if ( istate == 2 ) then
    ival = isgn * ival
    length = len_trim ( s )
  else
    ierror = 1
    length = 0
  end if

  return
end
subroutine s_to_i4vec ( s, n, ivec, ierror )

!*****************************************************************************80
!
!! S_TO_I4VEC reads an I4VEC from a string.
!
!  Modified:
!
!    08 October 2003
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input, character ( len = * ) S, the string to be read.
!
!    Input, integer N, the number of values expected.
!
!    Output, integer IVEC(N), the values read from the string.
!
!    Output, integer IERROR, error flag.
!    0, no errors occurred.
!    -K, could not read data for entries -K through N.
!
  implicit none

  integer n

  integer i
  integer ierror
  integer ilo
  integer ivec(n)
  integer length
  character ( len = * ) s

  i = 0

  ilo = 1

  do while ( i < n )

    i = i + 1

    call s_to_i4 ( s(ilo:), ivec(i), ierror, length )

    if ( ierror /= 0 ) then
      ierror = -i
      exit
    end if

    ilo = ilo + length

  end do

  return
end
subroutine s_word_count ( s, nword )

!*****************************************************************************80
!
!! S_WORD_COUNT counts the number of "words" in a string.
!
!  Modified:
!
!    14 April 1999
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input, character ( len = * ) S, the string to be examined.
!
!    Output, integer NWORD, the number of "words" in the string.
!    Words are presumed to be separated by one or more blanks.
!
  implicit none

  logical blank
  integer i
  integer lens
  integer nword
  character ( len = * ) s

  nword = 0
  lens = len ( s )

  if ( lens <= 0 ) then
    return
  end if

  blank = .true.

  do i = 1, lens

    if ( s(i:i) == ' ' ) then
      blank = .true.
    else if ( blank ) then
      nword = nword + 1
      blank = .false.
    end if

  end do

  return
end
subroutine timestamp ( )

!*****************************************************************************80
!
!! TIMESTAMP prints the current YMDHMS date as a time stamp.
!
!  Example:
!
!    May 31 2001   9:45:54.872 AM
!
!  Modified:
!
!    15 March 2003
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    None
!
  implicit none

  character ( len = 40 ) string

  call timestring ( string )

  write ( *, '(a)' ) trim ( string )

  return
end
subroutine timestring ( string )

!*****************************************************************************80
!
!! TIMESTRING writes the current YMDHMS date into a string.
!
!  Example:
!
!    STRING = 'May 31 2001   9:45:54.872 AM'
!
!  Modified:
!
!    15 March 2003
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Output, character ( len = * ) STRING, contains the date information.
!    A character length of 40 should always be sufficient.
!
  implicit none

  character ( len = 8 ) ampm
  integer d
  character ( len = 8 ) date
  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
  character ( len = * ) string
  character ( len = 10 ) time
  integer values(8)
  integer y
  character ( len = 5 ) zone

  call date_and_time ( date, time, zone, 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 ( string, '(a,1x,i2,1x,i4,2x,i2,a1,i2.2,a1,i2.2,a1,i3.3,1x,a)' ) &
    trim ( month(m) ), d, y, h, ':', n, ':', s, '.', mm, trim ( ampm )

  return
end
subroutine triangulation_order6_to_order3 ( tri_num1, triangle1, tri_num2, &
  triangle2 )

!*****************************************************************************80
!
!! TRIANGULATION_ORDER6_TO_ORDER3 linearizes a quadratic triangulation.
!
!  Discussion:
!
!    A quadratic triangulation is assumed to consist of 6-node triangles,
!    as in the following:
!
!    11-12-13-14-15
!     |\    |\    |
!     | \   | \   |
!     6  7  8  9 10
!     |   \ |   \ |
!     |    \|    \|
!     1--2--3--4--5
!
!   This routine rearranges information so as to define the 3-node
!   triangulation:
!
!    11-12-13-14-15
!     |\ |\ |\ |\ |
!     | \| \| \| \|
!     6--7--8--9-10
!     |\ |\ |\ |\ |
!     | \| \| \| \|
!     1--2--3--4--5
!
!  Modified:
!
!    22 March 2005
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input, integer TRI_NUM1, the number of triangles in the quadratic
!    triangulation.
!
!    Input, integer TRIANGLE1(6,TRI_NUM1), the quadratic triangulation.
!
!    Input, integer TRI_NUM2, the number of triangles in the linear
!    triangulation.  TRI_NUM2 = 4 * TRI_NUM1.
!
!    Output, integer TRIANGLE2(3,TRI_NUM2), the linear triangulation.
!
  implicit none

  integer tri_num1
  integer tri_num2

  integer n1
  integer n2
  integer n3
  integer n4
  integer n5
  integer n6
  integer tri1
  integer tri2
  integer triangle1(6,tri_num1)
  integer triangle2(3,tri_num2)

  tri2 = 0

  do tri1 = 1, tri_num1

    n1 = triangle1(1,tri1)
    n2 = triangle1(2,tri1)
    n3 = triangle1(3,tri1)
    n4 = triangle1(4,tri1)
    n5 = triangle1(5,tri1)
    n6 = triangle1(6,tri1)
    write ( *, * ) tri1, n1, n2, n3, n4, n5, n6
    tri2 = tri2 + 1
    triangle2(1:3,tri2) = (/ n1, n4, n6 /)
    tri2 = tri2 + 1
    triangle2(1:3,tri2) = (/ n2, n5, n4 /)
    tri2 = tri2 + 1
    triangle2(1:3,tri2) = (/ n3, n6, n5 /)
    tri2 = tri2 + 1
    triangle2(1:3,tri2) = (/ n4, n5, n6 /)

  end do

  return
end