Tetrahedron integration
- P. B. Allen, Phys. Stat. Sol. (b) 120, 629 (1983)
- Blöchl et al, Phys. Rev. B 16, 232 (1994)
- Add introduction to README
- Add references
- Full coverage
- Docs
- Improve gaussian with small e2-e1, e3-e2, e4-e3, Add tests
- Implement Blöchl correction (Eq. (22))
- Which diagonal to cut the cube into tetrahedron
- Modularize (e0, v0) -> (e1, ..., e8)
- Add type for piecewise polynomial (?)
- Functions other than gaussian (by quadrature integration?)