fesnt

Finite element Sn transport for math6641 project

Solve the 1D, 1G discrete ordinates neutron transport equation with a fairly flexible input structure.

Structure

fesnt.py - Main entry point. Can be used as a script as python3 fesnt.py <inputfile>. Will then create a pickled instance of the Manager object which stores all data and runs the show
mesh.py - Mesh objects that store material properties inside a single element. Responsible for solving a linear system given and updating iteration-wise fluxes
solver.py - Solver class that marches through time levels, angles, and meshes. Calls upon Mesh objects to solve the problems.
report - LaTeX document to build the report
figures - A collection of gifs and images that show how well the method works/doesn't work

Known issues

Due to some end of the semester travel, I had to get something to submit. There are some definite issues with this project, as detailed in the report and the TODO file. Time allowing I will attempt to polish up this project 🤞

Test functions used in the finite element method do not satisfy homogeneous Dirichlet boundary conditions across the element
Scattering and fission sources fail to propagate through to negative mu fluxes

Usage

When launching fesnt.py as a script, the pickled data can be loaded and then used to create gifs with the following simple two-step procedure

Make all the images - python script for de-pickling

# this chunk only needed to load the manager from the pickled file
import pickle
from fesnt import *

with open(<pickledFileHere>, 'rb') as inp:
  manager = pickle.load(inp)

# with any manager
manager.angularGif(pointsPerMesh=5)

Alternatively, load a manager from within python with

from fesnt import Manager
m = Manager('test.yaml')
m.main()

A collection on images will be saved in a directory matching the name of the input file, e.g. test.yaml ➡️ test/teststep<XYZ>.png

Convert the images to a gif The Image Magick convert function works very well for this. The gifs found in figures were produced with the following code

$ cd test
$ convert -delay 15 -loop 0 *.png test.fig

Some gifs

Pure absorber

Multi-region with fission and scattering

License

The full license can be found here

Copyright (C) Andrew Johnson, GTRC

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.