Add more entries to the parser

[espenfl]

This issue is a container for requests related to additions of new parser entries.

• additional energy entries

[espenfl]

There is a request to add other energy entries outside energy_no_entropy. #33 (comment).

[zhubonan]

The other thing that would be nice is the runtime timings such as the total runtime, scf time and ionic steps times. The last two can be obtained using grep LOOP OUTCAR while the first one is only printed at the end.

They can probably be used for estimating a suitable walltime limits for subsequent runs.

[zhubonan]

Hi @espenfl, I am trying to understand what the energy_no_entropy is.

I found the code here:

parsevasp/parsevasp/vasprun.py

Lines 1901 to 1911 in 44a3936

	for index, calc in enumerate(entries):
	# energy without entropy
	data = self._findall(calc,
	'.//scstep/energy/i[@name="e_0_energy"]')
	if data is None:
	return None
	data = self._convert_array1D_f(data)
	if index == 0:
	energies[1] = {'energy_no_entropy': [data[-1], data]}
	else:
	energies[index + 1] = {'energy_no_entropy': [data[-1], data]}

But it looks to me that it fetches the e_0_energy which is the extrapolated energy to 0 K (E-0.5TS). This is different from the e_fr_energy which is the energy that is minimised (free energy, E-TS), or e_wo_entrp which I think is the total energy (with fractional occupations).

Does this mean that energy_no_entropy is in fact E-0.5TS?

[espenfl]

@zhubonan Plan was to add the other energies, but did not get that far. Let us add all of those, so that the user can select. This also includes the components composing the total energy. Sometimes you want to have a look at that and we should support its extraction. Default should still be e_0_energy (energy(sigma->0) in OUTCAR) as this is the extrapolated one that tries to remove the sigma smearing contributions etc. This is typically slightly higher than the e_wo_entrp and is what many use for the total energy in VASP. When running with different sigma and you want to compare, you have to look at this one, otherwise you might get tricked by the differences being caused by differences in sigma etc. And so forth. But we should anyway support the extraction of the others. Currently, that is not implemented, but should be easy to do. If you want, please give it a go.

[zhubonan]

I see, yeah energy(sigma->0) is the one we want. Just that the naming is a bit confusing.
I will see if I can make it extract other energies as well. It could be useful when someone want to knwon how much the effect of SIGMA is having.

[lorenzovarrassi]

At the moment the parser does not fully support GW and response calculations.
It would be nice to add support for G0W0 and optics calculations (LOPTICS - BSE).