GetMeshOpt.m

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function Mesh=GetMeshOpt(cFileName)
% function Mesh=GetMesh(cFileName)
% Initialization of the Mesh structure from a FreeFEM++ mesh file -
% Optimized version
%
%
% Parameters:
%  cFileName: FreeFEM++ mesh file name (string)
%
% Return values:
%  Mesh: mesh structure
%
% Generated fields of Mesh:
%  q: Array of vertices coordinates, `2\times\nq` array. <br/>
%  `{\q}(\il,j)` is the
%  `\il`-th coordinate of the `j`-th vertex, `\il\in\{1,2\}` and
%  `j\in\ENS{1}{\nq}`
%  me: Connectivity array, `3\times\nme` array. <br/>
%  `\me(\jl,k)` is the storage index of the
%  `\jl`-th  vertex of the `k`-th triangle in the array `\q` of vertices coordinates, `\jl\in\{1,2,3\}` and
%       `k\in{\ENS{1}{\nme}}`.
%  ql: Array of vertices labels, `1\times\nq` array.
%  mel: Array of elements labels, `1\times\nme` array.
%  be: Connectivity array for boundary edges, `2\times\nbe` array.<br/>
% `\be(\il,l)` is the storage index of the
%  `\il`-th  vertex of the `l`-th edge in the array `\q` of vertices coordinates, `\il\in\{1,2\}` and
%       `l\in{\ENS{1}{\nbe}}`.
%  bel: Array of boundary edges labels, `1\times\nbe` array.
%  nq: total number of vertices, also denoted by `\nq`
%  nme: total number of elements, also denoted by `\nme`
%  nbe: total number of boundary edges, also denoted by `\nbe`
%  areas: Array of areas, `1\times\nme` array. areas(k) is the area of the `k`-th triangle.
%  lbe: Array of edges lengths,  `1\times\nbe` array. `\lbe(j)`  is the length of the `j`-th edge.
%
% See also
% #ComputeAreaOpt, #EdgeLength
% Example:
%  @verbatim 
%    Th=GetMeshOpt('disk.msh')
%  @endverbatim
% Copyright:
%   See \ref license

% Example:
%  @verbatim 
%    Th=GetMeshOpt('carre.msh')
%  @endverbatim
% @author François Cuvelier
%

  [fid,message]=fopen(cFileName,'r');
  if ( fid == -1 )
    error([message,' : ',cFileName]);
  end
  if isOctave()
  [n]=fscanf(fid,'%d %d %d',3);

  R=fscanf(fid,'%f %f %d',[3,n(1)]);
  q=R([1 2],:);
  ql=R(3,:);
  R=fscanf(fid,'%d %d %d %d',[4,n(2)]);

  me=R([1:3],:);
  mel=R(4,:);
  R=fscanf(fid,'%d %d %d',[3,n(3)]);
  
  be=R([1 2],:);
  bel=R(3,:);
  else % Matlab
  n=textscan(fid,'%d %d %d',1); % n(1) -> number of vertices
                      % n(2) -> number of triangles
                      % n(3) -> number of boundary edges
  
  R=textscan(fid,'%f %f %d',n{1});
  q=[R{1},R{2}]';
  ql=R{3}';
  R=textscan(fid,'%d %d %d %d',n{2});
  me=[R{1},R{2},R{3}]';
  mel=R{4}';

  R=textscan(fid,'%d %d %d',n{3});
  be=[R{1},R{2}]';
  bel=R{3}';
  end
  fclose(fid);

  Mesh=struct('q',q,'me',double(me),'ql',ql,'mel',double(mel), ...
              'be',double(be),'bel',double(bel), ...
              'nq',size(q,2), ...
              'nme',size(me,2), ...
              'nbe',size(be,2), ...
              'areas',ComputeAreaOpt(q,me),...
              'lbe',EdgeLength(be,q));