Materials project and atomate

Materials Project Materials Project Data/API
1

Materials project seems to use Atomate to generate its workflow data. However, it seems that a further processing is done to produce the results I get from the API as the keys are different from Atomate results, e.g. for elasticity data you have G_Reuss from MP API while g_reuss from Atomate. Can you please confirm or comment on this?

2

Hi @ladinesa, we indeed do post-processing on the data coming from atomate workflows using our emmet package before serving it up via the API. This may include name changes to the fields associated with different quantities.

– Jason

3

Hi @munrojm, thank you for your reply. I would like to know if the results for the other atomate workflows such as the equation of state and surface energies are available in the api results. I can only find the elasticity results so far in my api queries.

4

@ladinesa, I would suggest using the new API. Both the eos and surface energy data can be access via the eos and surface_properties endpoints. Instructions on how to access the new MPRester can be found here: Materials Project - API.

To get access to that data for silicon (mp-149) for example, you can do the following:

with MPRester(YOUR_API_KEY) as mpr:
    eos_data = mpr.eos.get_document_by_id("mp-149")
    surface_data = mpr.surface_properties.get_document_by_id("mp-149")
5

Thanks a lot! I will definitely give this a try. Is there any limit on the amount of api queries?

6

@ladinesa, the package will auto limit you at 100/min, but will do so politely. Meaning, it will simply pause for a brief period before continuing.

– Jason

7

@munrojm , the api works great. I would like to know if there is an endpoint for retrieving the vasp output files or at least the workflow ouput? Thanks!

8

@ladinesa, we are currently in the process of uploading the raw output files to the NOMAD repository (see NOMAD). Other than that, you can see which workflow steps and calculations (indexed by task_id values) are associated with a material using the calc_types field from the materials endpoint. From there, you can query the data that we parse from the vasprun.xml file(s) using the tasks endpoint. You can ask for the calcs_reversed field to get detailed input and output data. For a full list of task doc fields, see the sample output on the right hand side of this docs page: Materials Project API - ReDoc.

– Jason