function [ dim_num, node_num, element_num, element_order, node_data_num, ...
  node_coord, element_node, node_data ] = fem_read ( node_coord_file_name, ...
  element_file_name, node_data_file_name )

%% FEM_READ reads data files associated with a finite element solution.
%
%  Discussion:
%
%    This program reads the node, element and data files that define
%    a finite element geometry and data based on that geometry:
%    * a set of nodes, 
%    * a set of elements based on those nodes, 
%    * a set of data values associated with each node.
%
%  Modified:
%
%    26 January 2006
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, character NODE_COORD_FILE_NAME(*), the name of the node coordinate
%    file.  If this argument is not supplied, it will be requested.  If the interactive
%    response is blank, or otherwise defective, then the program terminates.
%
%    Input, character ELEMENT_FILE_NAME(*), the name of the element file.  If
%    this argument is not supplied, it will be requested.  If the interactive
%    response is blank, then the program will assume that no element information
%    is to be supplied.  (But the node coordinates must be available and may be plotted.
%    And if a node data file is supplied, then the data can be plotted against
%    the node coordinates without using any finite element structure.)
%
%    Input, character NODE_DATA_FILE_NAME(*), the name of the node data file.  If
%    this argument is not supplied, it will be requested.  If the interactive
%    response is blank, then the program will assume that no node data information
%    is to be supplied.  (But the node coordinates will be available and may be plotted.
%    And if an element file is supplied, then the elements can also be displayed.)
%
%    Output, integer DIM_NUM, the spatial dimension, inferred from the
%    "shape" of the data in the node file.
%
%    Output, integer NODE_NUM, the number of nodes, inferred from the 
%    number of lines of data in the node coordinate file.
%
%    Output, integer ELEMENT_NUM, the number of elements, inferred from the
%    number of lines of data in the element file.
%
%    Output, integer ELEMENT_ORDER, the order of the elements, inferred from
%    the number of items in the first line of the element file.
%
%    Output, integer NODE_DATA_NUM, the number of data items per node,
%    inferred from the number of items in the first line of the node data file.
%
%    Output, real NODE_COORD(DIM_NUM,NODE_NUM), the coordinates of nodes.
%
%    Output, integer ELEMENT_NODE(ELEMENT_ORDER,ELEMENT_NUM); 
%    the global index of local node I in element J.
%
%    Output, real NODE_DATA(NODE_DATA_NUM,NODE_NUM), the data values associated
%    with each node.
%

%
%  Read the node coordinate file.
%
  [ dim_num, node_num ] = dtable_header_read ( node_coord_file_name );

  [ element_order, element_num ] = itable_header_read ( element_file_name );

  [ node_data_num, node_num2 ] = dtable_header_read ( node_data_file_name );

  if ( node_num2 ~= node_num )
    fprintf ( 1, '\n' );
    fprintf ( 1, ...
      '  The number of nodes in the node coordinate file is %d.\n', ...
      node_num );
    fprintf ( 1, ...
      '  but the number in the node data file is %d\n', node_num2 );
    fprintf ( 1, '  Because of this, no node data will be stored.\n' );
    node_data_num = 0;
  end

  node_coord = dtable_data_read ( node_coord_file_name, dim_num, node_num );

  element_node = itable_data_read ( element_file_name, element_order, ...
    element_num );

  node_data = dtable_data_read ( node_data_file_name, node_data_num, node_num );