Tetrangulation of the master mesh

The master mesh must consist of volumetric elements, i.e. linear or quadratic hexahedra, wedges or tetrahedra. For each element type a remeshing into linear tetrahedral elements was devised: a C3D8, C3D6, C3D20(R), C3D15 and C3D10 element is mesh with 6 (field i1 in getuncrackedresults.c), 3 (field i2), 22 (field i4), 14 (field i5) and 8 (field i6) linear tetrahedra, respectively. Subsequently, the centers of gravity of the resulting tetrahedra are calculated and sorted according to the global x-values, the global y-values and global z-values. Furthermore, the element numbers of the original parent elements of these tetrahedra (several tetrahedra share one parent element) are stored in fields elemnr (original element numbers; may exhibit gaps) and iparent (continuous increasing numbers starting at 1). All values are frequently stored in fields integerglob and doubleglob for further use at the time of interpolation.