/usr/share/octave/packages/fpl-1.3.5/pdesurf.m is in octave-fpl 1.3.5-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 | ## Copyright (C) 2010 Carlo de Falco
##
## 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 3 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/>.
##
## author: Carlo de Falco <cdf _AT_ users.sourceforge.net>
## -*- texinfo -*-
## @deftypefn {Function File} {@var{h} =} pdesurf (@var{p}, @var{t}, @var{u})
##
## Plot a 3D surface given node or element data on a triangular mesh.
## @var{p}, @var{t} are the mesh vertices and connectivity, @var{u} node or element data.
##
## @seealso{fpl_dx_write_field, fpl_vtk_write_field}
##
## @end deftypefn
function h = pdesurf (p, t, u)
## Check input
if nargin!=3
error("pdesurf: wrong number of input parameters");
endif
nel = columns (t);
npt = columns (p);
if (numel (u) != npt && numel (u) != nel)
error("pdesurf: wrong data size");
endif
hs = ishold ();
### node data
if (numel (u) == npt)
## normalize data
c = colormap;
uc = sum (u(t(1:3, :)), 1)/3;
uc = floor ((rows (c)-1)*(uc - min (uc))/(max (uc) - min (uc))) + 1;
H = patch ('Faces', t(1:3, :)',
'Vertices', [p(1,:)', p(2,:)', u],
'FaceVertexCData', c(uc(:), :));
### triangle data
elseif (numel (u) == nel)
tri = reshape (1:3*nel, 3, [])';
pt(:, 1) = p(1, t(1:3, :));
pt(:, 2) = p(2, t(1:3, :));
pt(:, 3) = repmat (u(:)', 3, 1)(:);
## normalize data
c = colormap;
uc = floor ((rows (c)-1)*(u - min (u))/(max (u) - min (u))) + 1;
H = patch ('Faces', tri,
'Vertices', pt,
'FaceVertexCData', c(uc(:), :),
'FaceColor', 'flat');
endif
if (nargout == 1)
h = H;
endif
if (hs)
hold on;
else
hold off;
endif
endfunction
%!demo
%! msh = msh2m_structured_mesh ([0:.05:1], [0:.1:1], 1, 1:4, 'random');
%! x = msh.p(1,:)'; xm = sum(x(msh.t(1:3,:)),1)/3;
%! y = msh.p(2,:)'; ym = sum(y(msh.t(1:3,:)),1)/3;
%! pdesurf (msh.p, msh.t, x.*(1-x).*y.*(1-y))
%! title ('node data')
%! view(3)
%! figure ()
%! pdesurf (msh.p, msh.t, xm.*(1-xm).*ym.*(1-ym))
%! title ('element data')
%! view(3)
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