inaccurate description of psp_cutoff_table in 00_basic_usage.ipynb

[deyulu]

The description of the format of psp_cutoff_table is inaccurate. It strictly requires a json format.

[FCMeng]

{ 'Ag': {'filename': 'Ag.upf', 'cutoff_wfc': 50.0, 'cutoff_rho': 200.0}, }

This is a json format. This is not an assignment to a variable. The idea I put this format here is in case users will write their cutoff table by themselves.

The cutoff table from SSSP can be found at https://archive.materialscloud.org/record/file?record_id=1732&filename=SSSP_1.3.0_PBE_precision.json.

[matthewcarbone]

@FCMeng I talked to Deyu about this a bit. Basically the issue is it's just written confusingly in the notebook. I.e., it's written like a variable declaration in the notebook but someone unfamiliar with json might not know that you need to omit the variable part.

[deyulu]

@FCMeng @matthewcarbone I have two concrete suggestions. 1) Clarify that the file needs to be in a json format and provide the SSSP cutoff table link to give users a reference. The purpose of this description is to help users to prepare this file. If I literally copy and paste the current section in the notebook: cutoff_table = { 'Ag': {'filename': 'Ag.upf', 'cutoff_wfc': 50.0, 'cutoff_rho': 200.0}, } to a cutoff table file, Lightshow will throw out an error. One needs to remove " cutoff_table =" at the beginning and replace ' with ". For users who have no experience with json, they won't figure this out by themselves and could get confused. 2) Revise the example of Ag and provide the correct info for Ti and O, since the example of the notebook is for Ti compound.

[matthewcarbone]

Resolved in #189.