Public Data Access Overview / Discussion Forum

I am attempting to run this block of code in the image in order to extract the sub halo ID along with how many major mergers it has undergone:
Screenshot 2025-11-13 at 6.44.21 PM.png

This error comes up - I have already downloaded all the merger trees so I am not sure why this is:

OSError: Unable to synchronously open file (truncated file: eof = 10976975296, sblock->base_addr = 0, stored_eof = 12127878566)

Any help would be greatly appreciated!!

Sounds like a corrupt HDF5 file, suggest to redownload the file that is causing the issue.

I tried redownloading the file and the same error is still an issue - any idea what else I can try?

Can you please post a minimal, working code example, that reproduces the problem?

In the above screenshot, this means e.g. the values of basepath, and so on.

Can you also clarify if you are running this code on your own system, after downloading file(s), or if you are running on the Lab.

I am running the code on the JupyterLab interface.

I am not exactly sure what you mean by a minimal working code example - but here is the error that pops up.link text

Please see minimal reproducible example.

This is what the error boils down to - the issue is with when I use loadTree. I have attached the MRE that reproduces the same error that I posted previously.

When I start python in the Lab and run:

import illustris_python as il
basePath = 'sims.TNG/TNG300-1/output/'
fields = ['SubhaloID','NextProgenitorID','MainLeafProgenitorID','FirstProgenitorID','SubhaloMassType']
tree = il.sublink.loadTree(basePath,99,0,fields=fields)
tree['count']

736368

everything works ok.

If the error occurs only when you ask for the tree of subhalo ID 4294967295, then this is not a valid subhalo ID, and the answer is in your other thread.