Add extractNodes function

matlab/src/extractNodes.m

@@ -0,0 +1,91 @@
+function [int_xyz, int_i, n_xyz, n_i, nodes] = extractNodes(filename)
+% extractNodes -
+%
+% Syntax: [n_xyz, nodes] = extractNodes(filename)
+%
+% Inputs:
+%    - filename - relative or absolute path of the file that contains the Matrix
+%
+% Outputs:
+%    - n_xyz -
+%    - nodes - table containing the node numbers and corresponding dof of the interfaced DoFs
+
+arguments
+    filename
+end
+
+fid = fopen(filename,'rt');
+
+if fid == -1
+    error('Error opening the file');
+end
+
+n_xyz = []; % Contains nodes coordinates
+n_i = []; % Contains nodes indices
+
+n_num = []; % Contains node numbers
+n_dof = {}; % Contains node directions
+
+while 1
+    % Read a line
+    nextline = fgetl(fid);
+
+    % End of the file
+    if ~isstr(nextline), break, end
+
+    % Line just before the list of nodes coordinates
+    if contains(nextline, 'NODE') && ...
+            contains(nextline, 'X') && ...
+            contains(nextline, 'Y') && ...
+            contains(nextline, 'Z')
+
+        while 1
+            nextline = fgetl(fid);
+
+            if nextline < 0, break, end
+
+            c = sscanf(nextline, ' %f');
+
+            if isempty(c), break, end
+
+            n_xyz = [n_xyz; c(2:4)'];
+            n_i = [n_i; c(1)];
+        end
+    end
+
+    if nextline < 0, break, end
+
+    % Line just before the list of node DOF
+  if contains(nextline, 'NODE') && ...
+         contains(nextline, 'LABEL')
+
+        while 1
+            nextline = fgetl(fid);
+
+            if nextline < 0, break, end
+
+            c = sscanf(nextline, ' %d %s');
+
+            if isempty(c), break, end
+
+            n_num = [n_num; c(1)];
+
+            n_dof{length(n_dof)+1} = char(c(2:end)');
+        end
+
+        nodes = table(n_num, string(n_dof'), 'VariableNames', {'node_i', 'node_dof'});
+    end
+
+    if nextline < 0, break, end
+end
+
+fclose(fid);
+
+int_i = unique(nodes.('node_i')); % indices of interface nodes
+
+% Extract XYZ coordinates of only the interface nodes
+if length(n_xyz) > 0 && length(n_i) > 0
+    int_xyz = n_xyz(logical(sum(n_i.*ones(1, length(int_i)) == int_i', 2)), :);
+else
+    int_xyz = n_xyz;
+end