Voigt notation in output
When looking at Wiki and other resources about Voigt notation we find:
xx, yy, zz, yz, xz, xy
which I can easily remember as this:
x, y, z, not x, not y, not z
However, the Voigt representation output in Siesta (write_subs
) does:
x, y, z, xy, yz, xz
which is not standard.
I propose we either:
- Add what the Voigt representation means in the output, or
- Change to the conventional Voigt notation
I am more in favour of 2. since that would be more stable going forward.