Limited functionality for simulations ran with nightly build FDS version

[ManuelOsburg]

I have identical two FDS simulations. One was run with FDS-6.8.0-release and another with FDS-6.8.0-1386-g42fde33-nightly. While there are no problems with the simulation calculated with FDS-release, the fdsreader functionality is limited with the simulation calculated with FDS-nightly. In particular, the BNDF files cannot be read.

FDS-release

FDS-nightly:

[JanVogelsang]

Yes, that might very well be the case, as the nightly build incorporates wild changes of the FDS development team that might very well never make it to an actual release. As the FDS team is not supporting this project in any way, it's impossible to keep up with their daily changes. It's even difficult to make the FDSreader compatible with various FDS release versions, as the FDS team is not managing to make their versions backward-compatible.
So unfortunately, we can't offer any support for nightly builds. They might work, but might also not work. You can create an issue at FDS thought and indicate that their nightly builds are not producing the same (binary) outputs as their release versions, but I would assume they are aware of that and simply don't guarantee any consistency between versions.

[amarcozzi]

Hi, @JanVogelsang. Now that these changes have transitioned from the nightly release to the new minor release version 6.9 of FDS, would you be open to integrating this change? I have a member of my team that can work on a fix for the new output file format.

[JanVogelsang]

@amarcozzi Sure thing, such a fix would be very welcome! He could either create a pull request directly or just describe how the file format has changed, so that I can integrate the changes into the code!

[amarcozzi]

Thanks, @JanVogelsang. My teammate and I talked about this yesterday and she's going to start looking into a fix. This is related to issue #73 as well just so you're aware.

[briannak7]

@JanVogelsang, the FDS developers informed me that the .bnd files have been changed and no longer output the minimum and maximum values for each timestep.

When looking at the source code for fdsreader, it appears that Simulation._load_boundary_data is reading the number of timesteps (n_t) from these .bnd files. Consequently, when the Patch object is created in this method, n_t is set to 1 due to the file changes. This is why, I think, we’re only seeing the one timestep of boundary data.

Since these files are now differently structured, I wondered if reading in the data from the .bf files rather than the .bnd files would be a good approach. If so, any ideas on how to start with this change would be appreciated!

[JanVogelsang]

@briannak7 Are they now outputting the number of time steps somewhere in .bf files instead? If not it's quite difficult to read in the data, as you can't just read in binary data without knowing how you should actually interpret the data. It might be possible to calculate the number of time steps using the file size though, I think I have done that for some other data type as well.