/usr/share/octave/packages/msh-1.0.10/msh2m_submesh.m is in octave-msh 1.0.10-5.
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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 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 | ## Copyright (C) 2006,2007,2008,2009,2010 Carlo de Falco, Massimiliano Culpo
##
## This file is part of:
## MSH - Meshing Software Package for Octave
##
## MSH 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.
##
## MSH 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 MSH; If not, see <http://www.gnu.org/licenses/>.
##
## author: Carlo de Falco <cdf _AT_ users.sourceforge.net>
## author: Massimiliano Culpo <culpo _AT_ users.sourceforge.net>
## -*- texinfo -*-
## @deftypefn {Function File} {[@var{omesh},@var{nodelist},@var{elementlist}]} = @
## msh2m_submesh(@var{imesh},@var{intrfc},@var{sdl})
##
## Extract the subdomain(s) in @var{sdl} from @var{imesh}.
##
## The row vector @var{intrfc} contains the internal interface sides to
## be maintained (field @code{mesh.e(5,:)}). It can be empty.
##
## Return the vectors @var{nodelist} and @var{elementlist} containing
## respectively the list of nodes and elements of the original mesh that
## are part of the selected subdomain(s).
##
## @seealso{msh2m_join_structured_mesh, msh3m_submesh,
## msh3e_surface_mesh}
## @end deftypefn
function [omesh,nodelist,elementlist] = msh2m_submesh(imesh,intrfc,sdl)
## Check input
if nargin != 3
error("msh2m_submesh: wrong number of input parameters.");
endif
if !isstruct(imesh)
error("msh2m_submesh: first input is not a valid mesh structure.");
endif
if !isvector(sdl)
error("msh2m_submesh: third input is not a valid vector.");
endif
## Extract sub-mesh
nsd = length(sdl); # number of subdomains
## Set list of output triangles
elementlist=[];
for isd=1:nsd
elementlist = [elementlist find(imesh.t(4,:) == sdl(isd))];
endfor
omesh.t = imesh.t(:,elementlist);
## Set list of output nodes
nodelist = unique(reshape(imesh.t(1:3,elementlist),1,[]));
omesh.p = imesh.p(:,nodelist);
## Use new node numbering in connectivity matrix
indx(nodelist) = [1:length(nodelist)];
iel = [1:length(elementlist)];
omesh.t(1:3,iel) = indx(omesh.t(1:3,iel));
## Set list of output edges
omesh.e =[];
for isd=1:nsd
omesh.e = [omesh.e imesh.e(:,imesh.e(7,:)==sdl(isd))];
omesh.e = [omesh.e imesh.e(:,imesh.e(6,:)==sdl(isd))];
endfor
omesh.e=unique(omesh.e',"rows")';
## Use new node numbering in boundary segment list
ied = [1:size(omesh.e,2)];
omesh.e(1:2,ied) = indx(omesh.e(1:2,ied));
endfunction
%!test
%! [mesh1] = msh2m_structured_mesh(0:.5:1, 0:.5:1, 1, 1:4, 'left');
%! [mesh2] = msh2m_structured_mesh(1:.5:2, 0:.5:1, 1, 1:4, 'left');
%! [mesh] = msh2m_join_structured_mesh(mesh1,mesh2,2,4);
%! [omesh,nodelist,elementlist] = msh2m_submesh(mesh,[],2);
%! p = [1.00000 1.00000 1.00000 1.50000 1.50000 1.50000 2.00000 2.00000 2.00000
%! 0.00000 0.50000 1.00000 0.00000 0.50000 1.00000 0.00000 0.50000 1.00000];
%! e = [1 1 2 3 4 6 7 8
%! 2 4 3 6 7 9 8 9
%! 0 0 0 0 0 0 0 0
%! 0 0 0 0 0 0 0 0
%! 2 5 2 7 5 7 6 6
%! 2 0 2 0 0 0 0 0
%! 1 2 1 2 2 2 2 2];
%! t = [1 2 4 5 2 3 5 6
%! 4 5 7 8 4 5 7 8
%! 2 3 5 6 5 6 8 9
%! 2 2 2 2 2 2 2 2];
%! nl = [7 8 9 10 11 12 13 14 15];
%! el = [9 10 11 12 13 14 15 16];
%! toll = 1e-4;
%! assert(omesh.p,p,toll);
%! assert(omesh.e,e);
%! assert(omesh.t,t);
%! assert(nodelist,nl);
%! assert(elementlist,el);
%!demo
%! name = [tmpnam ".geo"];
%! fid = fopen (name, "w");
%! fputs (fid, "Point(1) = {0, 0, 0, .1};\n");
%! fputs (fid, "Point(2) = {1, 0, 0, .1};\n");
%! fputs (fid, "Point(3) = {1, 0.5, 0, .1};\n");
%! fputs (fid, "Point(4) = {1, 1, 0, .1};\n");
%! fputs (fid, "Point(5) = {0, 1, 0, .1};\n");
%! fputs (fid, "Point(6) = {0, 0.5, 0, .1};\n");
%! fputs (fid, "Line(1) = {1, 2};\n");
%! fputs (fid, "Line(2) = {2, 3};\n");
%! fputs (fid, "Line(3) = {3, 4};\n");
%! fputs (fid, "Line(4) = {4, 5};\n");
%! fputs (fid, "Line(5) = {5, 6};\n");
%! fputs (fid, "Line(6) = {6, 1};\n");
%! fputs (fid, "Point(7) = {0.2, 0.6, 0};\n");
%! fputs (fid, "Point(8) = {0.5, 0.4, 0};\n");
%! fputs (fid, "Point(9) = {0.7, 0.6, 0};\n");
%! fputs (fid, "BSpline(7) = {6, 7, 8, 9, 3};\n");
%! fputs (fid, "Line Loop(8) = {6, 1, 2, -7};\n");
%! fputs (fid, "Plane Surface(9) = {8};\n");
%! fputs (fid, "Line Loop(10) = {7, 3, 4, 5};\n");
%! fputs (fid, "Plane Surface(11) = {10};\n");
%! fclose (fid);
%! mesh = msh2m_gmsh (canonicalize_file_name (name)(1:end-4), "clscale", ".5");
%! mesh1 = msh2m_submesh (mesh, 7, 9);
%! subplot (1, 2, 1);
%! trimesh (mesh.t(1:3,:)', mesh.p(1,:)', mesh.p(2,:)');
%! axis ("equal"); title ("full mesh")
%! subplot (1, 2, 2);
%! trimesh (mesh1.t(1:3,:)', mesh1.p(1,:)', mesh1.p(2,:)');
%! axis ("equal"); title ("sub-mesh")
%! unlink (canonicalize_file_name (name))
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