Displacement output

[CsatiZoltan]

Hi,

In section 2.1.6 Printing Results of the documentation, the nodal coordinates and velocities are available but not the displacements. I guess that this is because FEPX solves a time-dependent (elasto-visco-plastic) problem. However, I would need to have access to the displacements as well, which can easily be determined from the nodal coordinates. Is there a reason why it is not implemented in FEPX? If it will soon be available in a future release, I may wait to implement it by myself...

Thank you,
Zoltan

[mkasemer]

@CsatiZoltan - you are right that it is relatively easy to calculate displacements, either in-code or during post-processing. We are working on a new release for sometime early next week (the plan was today, but a bug was found). I can attempt to add displacement output to the next release, but otherwise I will let you know, and you could submit a pull request with changes. I assume you would prefer total (cumulative) displacements, rather than incremental?

In the meantime, if it cannot wait until Monday or so, Neper should have the ability to perform such mathematical manipulations during post-processing. @rquey could comment here.

[rquey]

Okay, -noderes disp is now live in Neper (which will still be useful if it was not among FEPX's output). (not documented yet)

@CsatiZoltan It should be possible to get a functional Neper without admin access, although it is certainly no fun. You would have to install the dependencies locally and link them. Most Neper dependencies are optional and can be switched off. Only GSL is mandatory but it can be compiled easily (it has no dependency). The next release of Neper will have some of its dependencies built-in to ease installation.

[CsatiZoltan]

Thank you, @rquey
As I wanted to perform the visualization on the cluster (no need to move results from the cluster to the local machine, and also Neper is parallelized so the visualization is faster), I needed the GSL and the POV-Ray dependencies. As conda is available on the university cluster (as part of the Anaconda distribution), I could make use of it. This is how I installed Neper:

1. Activate the Anaconda module on the cluster

   $ module load anaconda3/2020.02

2. Create a conda environment from the following file (environment.yml)

   name: Neper
   channels:
   - conda-forge
   dependencies:
   - povray
   - neper
   

   $ conda env create -f environment.yml

3. Activate that environment and check if Neper is indeed installed locally

   $ conda activate Neper
   $ which neper
   ~/.conda/envs/Neper/bin/neper

I hope it helps others. The downsides of this approach:

• it doesn't use the latest version of Neper: https://anaconda.org/conda-forge/neper
• the created environment takes more than 2 GB of space (not a big issue on a cluster, though)

[mkasemer]

@CsatiZoltan: please note that the release was again delayed (more bugs!) but that it is coming imminently. The Neper fix should work for the interim.

[mkasemer]

@CsatiZoltan: FEPX v1.2.0 has been released, which contain some updates to output (among other things). Please note that you may need to update to Neper v4.2.0 for full compatibility.

[CsatiZoltan]

@mkasemer Wow, great news. Big thanks to the FEPX and Neper developers!