xmlmesh(vrts,tets)
xmlmesh(vrts,tets,'filename.xml')
xmlmesh(____,'doctype','xmlns')

xmlmesh() takes a set of 2D or 3D vertices (vrts) and a tetrahedral (tets)
connectivity list, and creates an XML file of the mesh. This function was
originally created to export xml mesh files for using in Fenics:Dolfin
but can be adapted for universal xml export of triangulated meshes.

xmlmesh(vrts,tets)
    creates an XML file 'xmlmesh.xml' from a set of vertices "vrts"
    and a connectivity list; here the connectivity list is referred
    to as "tets". These parameters can be generated manually, or by
    using matlab's builtin triangulation functions. The point list
    "vrts" is a matrix with dimensions Mx2 (for 2D) or Mx3 (for 3D).
    The matrix "tets" represents the triangulated connectivity list
    of size Mx3 (for 2D) or Mx4 (for 3D), where M is the number of
    triangles. Each row of tets specifies a triangle defined by indices
    with respect to the points. The delaunayTriangulation function
    can be used to quickly generate these input variables:
        TR = delaunayTriangulation(XYZ);
        vrts = TR.Points;
        tets = TR.ConnectivityList;


xmlmesh(vrts,tets,'filename.xml')
    same as above, but allows you to specify the xml filename.


xmlmesh(____,'doctype','xmlns')
    same as above, but allows you to additionally specify the
    xml namespace xmlns attribute. For details see:
    http://www.w3schools.com/xml/xml_namespaces.asp

XY = randn(10,2);
TR2D = delaunayTriangulation(XY);
vrts = TR2D.Points;
tets = TR2D.ConnectivityList;
xmlmesh(vrts,tets,'xmlmesh_2D.xml')

d = [-5 8];
[x,y,z] = meshgrid(d,d,d); % a cube
XYZ = [x(:) y(:) z(:)];
TR3D = delaunayTriangulation(XYZ);
vrts = TR3D.Points;
tets = TR3D.ConnectivityList;
xmlmesh(vrts,tets,'xmlmesh_3D.xml')

<?xml version="1.0" encoding="utf-8"?>
<dolfin xmlns:dolfin="bradleymonk.com/xmlmesh">
   <mesh celltype="tetrahedron" dim="2">
      <vertices size="10">
         <vertex index="0" x="-2.9375e-01" y="-1.33200e+00"/>
         <vertex index="1" x="-8.4792e-01" y="-2.32986e+00"/>
         <vertex index="2" x="-1.1201e+00" y="-1.44909e+00"/>
         <vertex index="3" x="2.52599e+00" y="3.335108e-01"/>
         <vertex index="4" x="1.65549e+00" y="3.913536e-01"/>
         <vertex index="5" x="3.075351e-01" y="4.51679e-01"/>
         <vertex index="6" x="-1.25711e+00" y="-1.3028e-01"/>
         <vertex index="7" x="-8.65468e-01" y="1.83689e-01"/>
         <vertex index="8" x="-1.76534e-01" y="-4.7615e-01"/>
         <vertex index="9" x="7.914160e-01" y="8.62021e-01"/>
      </vertices>
      <cells size="12">
         <tetrahedron index="0" v0="2" v1="1" v2="0"/>
         <tetrahedron index="1" v0="5" v1="9" v2="7"/>
         <tetrahedron index="2" v0="2" v1="0" v2="8"/>
         <tetrahedron index="3" v0="6" v1="2" v2="8"/>
         <tetrahedron index="4" v0="8" v1="5" v2="7"/>
         <tetrahedron index="5" v0="8" v1="4" v2="5"/>
         <tetrahedron index="6" v0="4" v1="3" v2="9"/>
         <tetrahedron index="7" v0="6" v1="8" v2="7"/>
         <tetrahedron index="8" v0="0" v1="4" v2="8"/>
         <tetrahedron index="9" v0="5" v1="4" v2="9"/>
         <tetrahedron index="10" v0="0" v1="1" v2="3"/>
         <tetrahedron index="11" v0="0" v1="3" v2="4"/>
      </cells>
   </mesh>
</dolfin>

<?xml version="1.0" encoding="utf-8"?>
<dolfin xmlns:dolfin="bradleymonk.com/xmlmesh">
   <mesh celltype="tetrahedron" dim="3">
      <vertices size="8">
         <vertex index="0" x="-5.00000e+00" y="-5.0000e+00" z="-5.00000e+00"/>
         <vertex index="1" x="-5.00000e+00" y="8.00000e+00" z="-5.00000e+00"/>
         <vertex index="2" x="8.00000e+00" y="-5.00000e+00" z="-5.00000e+00"/>
         <vertex index="3" x="8.00000e+00" y="8.00000e+00" z="-5.00000e+00"/>
         <vertex index="4" x="-5.00000e+00" y="-5.0000e+00" z="8.00000e+00"/>
         <vertex index="5" x="-5.00000e+00" y="8.00000e+00" z="8.00000e+00"/>
         <vertex index="6" x="8.00000e+00" y="-5.00000e+00" z="8.00000e+00"/>
         <vertex index="7" x="8.00000e+00" y="8.00000e+00" z="8.00000e+00"/>
      </vertices>
      <cells size="6">
         <tetrahedron index="0" v0="4" v1="0" v2="1" v3="2"/>
         <tetrahedron index="1" v0="5" v1="4" v2="1" v3="2"/>
         <tetrahedron index="2" v0="5" v1="6" v2="4" v3="2"/>
         <tetrahedron index="3" v0="5" v1="3" v2="6" v3="2"/>
         <tetrahedron index="4" v0="5" v1="1" v2="3" v3="2"/>
         <tetrahedron index="5" v0="5" v1="7" v2="6" v3="3"/>
      </cells>
   </mesh>
</dolfin>