function  hidden_scp_er_est_surface ()
% Copyright 2000, J.E. Akin.  All rights reserved.
%  ------------------------------------------------------
%  Matlab carpet plot of scp est energy norm error
%  at mesh node locations
%  ------------------------------------------------------
 %? global az el   ? these are not changing with new view

% c_x    = x coordinates of nod_per_el line polygon
% c_y    = y coordinates of nod_per_el line polygon
% msh_typ_nodes   = connectivity list for elements, nt x nod_per_el
% loop   = corners for nod_per_el line polygon
% nod_per_el = Nodes per element
% np     = Number of Points
% nt     = Number of elements
% pre_e  = Element items before connectivity list
  pre_e  = 0 ;
% pre_p  = Nodal items before coordinates
  pre_p = 1;
% msh_bc_xyz = Nodal coordinates (with preceeding data)
% t_x    = x coordinates of nod_per_el corners
% t_y    = y coordinates of nod_per_el corners

%    Read coordinate file and connectivity file
%    integer bc code, real xy pairs for np points (pre_p = 1)
  load msh_bc_xyz.tmp ;  

%    Set control data: number of points
  np = size (msh_bc_xyz,1) ;   % number of nodal points  
  % fprintf ('Read %g mesh coordinate pairs \n', np)
  ns = size (msh_bc_xyz,2) - pre_p ;   % space dimension
  if ( ns < 2 )
    error ('This is not a 2D mesh')
  end % if not 2D data
  
%    Set control data: number elements
  load  msh_typ_nodes.tmp ; % nod_per_el nodes per element
  nt = size (msh_typ_nodes,1) ;          % number of elements in mesh 
  nod_per_el = size (msh_typ_nodes,2) - pre_e -1 ; % nodes per elem
  % fprintf ('Read %g elements connections \n', nt)

  load pt_ave_error_est.tmp
  nr = size (pt_ave_error_est, 1);
  if ( nr == 0 )
    error ('Error missing file pt_ave_error_est.tmp')
  end % if error
  max_p = size (pt_ave_error_est, 2) ; % number of columns
  % fprintf ('Read %g nodal solution values \n', nr)
  % fprintf ('     with %g components each \n', max_p)

  x (np)      = 0.       ;       % pre-allocate array x
  y (np)      = 0.       ;       % pre-allocate array y
  z (np)      = 0.       ;       % pre-allocate array z
  t_nodes (nod_per_el) = 0 ;    % Optional pre-allocation
  t_x (nod_per_el) = 0 ;        % Optional pre-allocation
  t_y (nod_per_el) = 0 ;        % Optional pre-allocation
  c_x (nod_per_el + 1) = 0 ;    % Optional pre-allocation
  c_y (nod_per_el + 1) = 0 ;    % Optional pre-allocation
  loop (nod_per_el + 1) = 0 ;   % Optional pre-allocation

%                set constants
  [loop] = get_El_Loop (nod_per_el) ;

  % msh_bc_xyz has: pre_p items then: x, y
  x = msh_bc_xyz (1:np, (pre_p+1)) ; % extract x column
  y = msh_bc_xyz (1:np, (pre_p+2)) ; % extract y column 
  z = pt_ave_error_est(:, 1) ;

%    Cite max, min values
  [V_X, L_X] = max (z) ;
  [V_N, L_N] = min (z) ;
  fprintf ('Max value is %g at node %g \n', V_X, L_X)
  fprintf ('Min value is %g at node %g \n', V_N, L_N)

%    Initialize plots
   xmax = max (x)      ; xmin = min (x) ;
   ymax = max (y)      ; ymin = min (y) ;
   zmax = max (z)      ; zmin = min (z) ;
% zmax= 5.5
   clf                               % clear graphics
   axis ([xmin, xmax, ymin, ymax, zmin, zmax])   % set axes
% view([52.5,30])


   hold on                           % hold image for plots
   xlabel ('X')                      % add label 
   ylabel ('Y')                      % add label
   zlabel ('SCP Average Nodal Error Est, % * 100');
   title(['FEA SCP Average Nodal Energy Norm Error: ', ...
            int2str(nt),' Elements, ', int2str(np), ...   
            ' Nodes (', int2str(nod_per_el), ' per Element)'])

%    Loop over all elements
  for it = 1:nt  ;

%      Extract corner connectivity 
    t_nodes = msh_typ_nodes (it, (pre_e+2):(nod_per_el+pre_e+1)); 
    if ( all ( t_nodes > 0 ) ) %B

%      Extract corner coordinates
      t_x  = x (t_nodes) ;         % x at those nodes, only
      t_y  = y (t_nodes) ;         % y at those nodes, only
      t_z  = z (t_nodes) ;         % z at those nodes, only

%      Plot this polygon
      c_x  = t_x (loop) ;       % x for nod_per_el line polygon
      c_y  = t_y (loop) ;       % y for nod_per_el line polygon
      c_z  = t_z (loop) ;
      fill3 (c_x, c_y, c_z, 'w'  )           % plot nod_per_el lines
    end % if all
  end % for over all elements
  grid
 
%% label max min points 
%  v_text = sprintf ('------min') ;
%  text  (x(L_N), y(L_N), V_N, v_text) ;
%  v_text = sprintf ('------max') ;
%  text  (x(L_X), y(L_X), V_X, [v_text]) ;   ;

% end % if show labels
%       -depsc -tiff            % for an eps version
% print ('-dpsc', ['hidden_scp_err_est_surf'])
  hold off
%  v_text = ['Created hidden_scp_err_est_surf.ps'] ;
% fprintf (1,'%s', v_text) ; fprintf (1, ' \n' )
% end of hidden_scp_er_est_surface