code

Signed-off-by: 刘明宏 <liuminghong@mail.sdu.edu.cn>

bin/RMT3d/get_edges.m

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+function [elems2edges, edges2nodes]=get_edges(elems2nodes)
+%function: [element2edges, edge2nodes]=get_edges(elems2nodes)
+%requires: deleterepeatedrows
+%generates edges of (triangular) triangulation defined in elems2nodes
+%elems2nodes is matrix, whose rows contain numbers of its element nodes 
+%element2edges returns edges numbers of each triangular element
+%edge2nodes returns two node numbers of each edge
+%example in 2D: [element2edges, edge2nodes]=get_edges([1 2 3; 2 4 3])
+%example in 3D: [element2edges, edge2nodes]=get_edges([1 2 3 4; 1 2 3 5; 1 2 4 6])
+ % Liu minghong 20221026   
+%2D case
+if (size(elems2nodes,2)==3)
+    %extracts sets of edges 
+    edges1=elems2nodes(:,[2 3]);
+    edges2=elems2nodes(:,[3 1]);
+    edges3=elems2nodes(:,[1 2]);
+
+    %as sets of their nodes (vertices)
+    vertices=zeros(size(elems2nodes,1)*3,2);
+    vertices(1:3:end,:)=edges1;
+    vertices(2:3:end,:)=edges2;
+    vertices(3:3:end,:)=edges3;
+
+    %repeated sets of nodes (joint edges) are eliminated 
+    [edges2nodes,elems2edges]=deleterepeatedrows(vertices);
+    elems2edges=reshape(elems2edges,3,size(elems2nodes,1))';
+end
+
+%3D case
+if (size(elems2nodes,2)==4)
+    %extracts sets of edges 
+    edges1=elems2nodes(:,[1 2]);
+    edges2=elems2nodes(:,[1 3]);
+    edges3=elems2nodes(:,[1 4]);
+    edges4=elems2nodes(:,[2 3]);     
+%     edges5=elems2nodes(:,[3 4]);
+%     edges6=elems2nodes(:,[4 2]);
+       % Liu minghong 20221026 
+    edges5=elems2nodes(:,[4 2]);
+    edges6=elems2nodes(:,[3 4]);
+        
+    %as sets of their nodes (vertices)
+    vertices=zeros(size(elems2nodes,1)*6,2);
+    vertices(1:6:end,:)=edges1;
+    vertices(2:6:end,:)=edges2;
+    vertices(3:6:end,:)=edges3;
+    vertices(4:6:end,:)=edges4;
+    vertices(5:6:end,:)=edges5;
+    vertices(6:6:end,:)=edges6;
+    
+    %repeated sets of nodes (joint edges) are eliminated 
+    [edges2nodes,elems2edges]=deleterepeatedrows(vertices);
+    elems2edges=reshape(elems2edges,6,size(elems2nodes,1))';
+    % *** 20221026
+    edges2nodes=sort(edges2nodes,2);
+    
+end
+
+
+function [matrix,I]=deleterepeatedrows(matrix)
+%function: [element2edges, edge2nodes]=edge_numbering(elements)
+%requires: deleterepeatedrows
+%generates edges of (triangular) triangulation defined in elements
+%elements is matrix, whose rows contain numbers of its element nodes 
+%element2edges returns edges numbers of each triangular element
+%edge2nodes returns two node numbers of each edge
+%example: [element2edges, edge2nodes]=edge_numbering([1 2 3; 2 4 3])
+
+
+%fast and short way suggested by John D'Ericco working in both 2D and 3D
+matrixs=sort(matrix,2);
+[dummy,J,I] = unique(matrixs,'rows');
+%I=reshape(I,size(matrixs,2),size(I,1)/size(matrixs,2));
+matrix=matrix(J,:);