+## Copyright (C) 2004-2008,2009 Carlo de Falco, Massimiliano Culpo
+##
+## This file is part of
+##
+## FPL - Fem PLotting package for octave
+##
+## FPL is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 2 of the License, or
+## (at your option) any later version.
+##
+## FPL is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with FPL; If not, see <http://www.gnu.org/licenses/>.
+##
+##
+## AUTHORS:
+## Carlo de Falco <cdf _AT_ users.sourceforge.net>
+##
+## Culpo Massimiliano
+## Bergische Universitaet Wuppertal
+## Fachbereich C - Mathematik und Naturwissenschaften
+## Arbeitsgruppe fuer Angewandte MathematD-42119 Wuppertal Gaussstr. 20
+## D-42119 Wuppertal, Germany
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {} FPL2pdesurf (@var{mesh}, @
+## @var{u} [ @var{property}, @var{value} ...])
+##
+## plots the scalar field @var{u}
+## defined on the triangulation @var{mesh} using opendx.
+##
+## options (default value):
+## @itemize @minus
+## @item data_dep ("positions") defines wether data depends on
+## positions or connections
+## @item plot_field ("scalar") defines wether to plot the scalar field
+## itself or its gradient
+## @end itemize
+##
+## @seealso{MSH2Mgmsh, MSH2Mstructmesh}
+## @end deftypefn
+
+function FPL2pdesurf(varargin)
+
+ data_dep = "positions";
+ plot_field = "scalar";
+
+ if nargin == 1
+ FPL2showmesh(varargin{1});
+ elseif nargin == 2
+ mesh = varargin{1};
+ u = varargin{2};
+ elseif ( (nargin > 2) && (rem(nargin,2)==0) )
+ mesh = varargin{1};
+ u = varargin{2};
+ for ii=3:2:nargin
+ eval([ varargin{ii} " = """ varargin{ii+1} """;" ]);
+ endfor
+ else
+ keyboard ,error(["wrong number of parameters " num2str (nargin)])
+ endif
+
+ dataname = mktemp("/tmp",".dx");
+ scriptname = mktemp("/tmp",".net");
+
+ FPL2dxoutputdata(dataname,mesh.p,mesh.t,u,'u',0,1,1);
+
+ switch plot_field
+ case {"scalar","scal"}
+ showmesh = file_in_path(path,"FPL2coloredrubbersheet.net");
+ case {"gradient","grad"}
+ showmesh = file_in_path(path,"FPL2coloredgradient.net");
+ otherwise
+ error ([ "incorrect value " plot_field " for option plot_field "])
+ endswitch
+
+ system (["cp " showmesh " " scriptname]);
+ system (["sed -i \'s|__FILE__DX__|" dataname "|g\' " scriptname]);
+
+ switch data_dep
+ case {"positions","continuous","interpolate","P1"}
+ system (["sed -i \'s|__DATA_DEPENDENCY__|positions|g\' " scriptname]);
+ case {"connections","discontinuous","P0"}
+ system (["sed -i \'s|__DATA_DEPENDENCY__|positions|g\' " scriptname]);
+ otherwise
+ error ([ "incorrect value " data_dep " for option data_dep "])
+ endswitch
+
+ ##command = ["dx -noConfirmedQuit -noImageRWNetFile -program " scriptname " -execute -image >& /dev/null & "];
+ command = ["dx -noConfirmedQuit -program " scriptname " -execute -image >& /dev/null & "];
+
+ system(command);
+
+endfunction
+
+function filename = mktemp (direct,ext);
+
+ if (~exist(direct,"dir"))
+ error("trying to save temporary file to non existing directory")
+ endif
+
+ done=false;
+
+ while ~done
+ filename = [direct,"/FPL.",num2str(floor(rand*1e7)),ext];
+ if ~exist(filename,"file")
+ done =true;
+ endif
+ endwhile
+
+endfunction
+
+%!shared msh
+%!demo
+%! msh.p = [0 0; 1 0; 1 1; 0 1].';
+%! msh.t = [1 2 3 1; 1 3 4 1].';
+%! msh.e = [1 2 0 0 1 0 1; 2 3 0 0 2 0 1; 3 4 0 0 3 0 1; 4 1 0 0 4 0 1].';
+%! u = [0 1].';
+%! FPL2pdesurf (msh, u, "data_dep", "connections");
+%! s = input ("do you see a square divided into two triangles with a diagonal red-to-blue gradient color (if you see an empty plot try ctrl-F)? (y/n): " ,"s");
+%! assert(s, "y")
+%!demo
+%! v = [0 0 1 1].';
+%! FPL2pdesurf (msh, v);
+%! s = input ("do you see a square divided into two triangles with a vertical red-to-blue gradient color (if you see an empty plot try ctrl-F)? (y/n): " ,"s");