missing header information in snapshot files (TNG100-1)

Duncan Campbell
  • 19 Mar '19


When I download a subset of particle data (following the example of task 11 in the Web API Documentation), the snapshot headers are missing at least some information. For example they are missing the 'NumPart_ThisFile' entry. This seems similar to the issue here: http://www.tng-project.org/data/forum/topic/109/missing-header-extract-subset-of-snapshots-particl/

Any suggestions for work arounds to this problem?


Dylan Nelson
  • 20 Mar '19

Hi Duncan,

I have added NumPart_ThisFile back to these type of cutouts, I had removed it since it could be ambiguous.

If you don't request a certain particle type, then it will have zero for these entries.

I left NumPart_Total alone (same as in the original snapshot files).

Duncan Campbell
  • 20 Mar '19

Hi Dylan,

Thanks. I think that is probably best since some of the illustris_python functions seem to require that header entry. I ended up writing a script to add that header information, also putting zeros for particle types not requested. Another option would be to provide such a script, or build that functionality into illustris_python.


Thanks again,

Dylan Nelson
  • 20 Mar '19

Yes I realized that the scripts may not actually work as is with cutouts, I had always assumed people would be reading cutouts "raw" (e.g. with h5py).

Let me know if there are any similar improvements that would help.

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