# HDF5 nuclear data converted from ACE **URL:** \ **Category:** User Support\ **Created:** [May 22, 2017, 10:46pm UTC](https://openmc.discourse.group/t/hdf5-nuclear-data-converted-from-ace/272 "2017-05-22T22:46:43Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![walshjon](https://avatars.discourse-cdn.com/v4/letter/w/cdc98d/32.png) [@walshjon](https://openmc.discourse.group/u/walshjon)\ **Post date:** [May 22, 2017, 10:46pm UTC](https://openmc.discourse.group/t/hdf5-nuclear-data-converted-from-ace/272/1 "2017-05-22T22:46:43Z")
I am able to convert ACE data to HDF5 (using the provided script) and run OpenMC (develop and various other branches) with that data locally. I am also able to run OpenMC with that locally-converted data on a cluster. However, when I do the conversion on the cluster, running OpenMC with the converted HDF5 data yields: HDF5-DIAG: Error detected in HDF5 (1.8.18) MPI-process 0: #000: H5F.c line 604 in H5Fopen(): unable to open file major: File accessibilty minor: Unable to open file I don’t think it’s an issue of the files’ existence or permissions. Are there any typical causes of this error when running OpenMC? Thanks, Jon ---
**Author:** ![paulromano](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/paulromano/32/486_2.png) [@paulromano](https://openmc.discourse.group/u/paulromano)\ **Post date:** [May 22, 2017, 11:39pm UTC](https://openmc.discourse.group/t/hdf5-nuclear-data-converted-from-ace/272/2 "2017-05-22T23:39:52Z")
Hi Jon, Is it possible that the filesystem the data is a local filesystem on a single node (i.e., other ranks don’t have access to the file)? Best, Paul ---
**Author:** ![walshjon](https://avatars.discourse-cdn.com/v4/letter/w/cdc98d/32.png) [@walshjon](https://openmc.discourse.group/u/walshjon)\ **Post date:** [May 23, 2017, 12:47am UTC](https://openmc.discourse.group/t/hdf5-nuclear-data-converted-from-ace/272/3 "2017-05-23T00:47:48Z")
With all data on the same filesystem, I am able to access HDF5 files that were converted from ACE locally and then transferred to the cluster, but when I hit a file (in the same run) that was converted on the cluster, I hit this error. I have ~TBs of ACE data I’m trying to convert, so I’d prefer to keep it on the cluster. ---
**Author:** ![paulromano](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/paulromano/32/486_2.png) [@paulromano](https://openmc.discourse.group/u/paulromano)\ **Post date:** [May 23, 2017, 1:57am UTC](https://openmc.discourse.group/t/hdf5-nuclear-data-converted-from-ace/272/4 "2017-05-23T01:57:45Z")
What version of HDF5 is your h5py installation linked against? You can find out by running import h5py print(h5py.h5.get\_libversion()) ---
**Author:** ![walshjon](https://avatars.discourse-cdn.com/v4/letter/w/cdc98d/32.png) [@walshjon](https://openmc.discourse.group/u/walshjon)\ **Post date:** [May 23, 2017, 2:26am UTC](https://openmc.discourse.group/t/hdf5-nuclear-data-converted-from-ace/272/5 "2017-05-23T02:26:20Z")
In the meantime, I built a new HDF5, and with gcc-4.9.3, mvapich2-2.2, and hdf5-1.10.1 everything is now working on the cluster. That said: – The erroring exe was built with gcc-4.9.3, mvapich2-2.2, and **hdf5-1.8.18 with the same configuration as the successful hdf5-1.10.1** – cluster h5py is linked against 1.10.0 – local h5py is linked against 1.8.13 So, the 1.8.18 openmc didn’t play well with the 1.10.0-generated data, but the 1.8.13-generated data was fine (as is 1.10.0-generated data with a 1.10.1 exe). Thanks for looking at this, Paul. ---
**Author:** ![paulromano](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/paulromano/32/486_2.png) [@paulromano](https://openmc.discourse.group/u/paulromano)\ **Post date:** [May 23, 2017, 2:29am UTC](https://openmc.discourse.group/t/hdf5-nuclear-data-converted-from-ace/272/6 "2017-05-23T02:29:52Z")
This is probably [the line](https://github.com/mit-crpg/openmc/blob/develop/openmc/data/neutron.py#L499) that bit you – we use libver=‘latest’ when creating HDF5 files using h5py, which may produce libraries that are incompatible with previous versions of HDF5 as described [here](http://docs.h5py.org/en/latest/high/file.html#version-bounding). Glad you got it working!