QXGraphDecompositions is a Julia package for analysing and manipulating graph structures describing tensor networks in the QuantEx project. It provides functions for solving graph theoretic problems related to the task of efficiently slicing and contracting a tensor network. Documentation can be found here.

QXGraphDecompositions was developed as part of the QuantEx project, one of the individual software projects of WP8 of PRACE 6IP.

QXGraphDecompositions is a Julia package and can be installed using Julia's inbuilt package manager from the Julia REPL using.

import Pkg
Pkg.add("QXGraphDecompositions")

To ensure everything is working, the unittests can be run using

import Pkg; Pkg.test()

An example of how QXGraphDecompositions can be used to calculate a vertex elimination order for a graph looks like:

using QXGraphDecompositions

# Create a LabeledGraph with N fully connected vertices.
N = 10
G = LabeledGraph(N)
for i = 1:N, j = i+1:N
    add_edge!(G, i, j)
end

# To get an elimination order for G with minimal treewidth we can use the min fill heuristic.
tw, elimination_order = min_fill(G);
@show elimination_order

# The treewidth of the elimination order is:
@show tw

Contributions from users are welcome and we encourage users to open issues and submit merge/pull requests for any problems or feature requests they have. The CONTRIBUTING.md has further details of the contribution guidelines.

QXTn.jl uses Documenter.jl to generate documentation. To build the documentation locally run the following from the root folder.

The first time it is will be necessary to instantiate the environment to install dependencies

julia --project=docs/ -e 'using Pkg; Pkg.develop(PackageSpec(path=pwd())); Pkg.instantiate()'

and then to build the documentation

julia --project=docs/ docs/make.jl

The generated document will be in the docs/build folder. To serve these locally one can use the LiveServer package as

julia --project -e 'import Pkg; Pkg.add("LiveServer");
julia --project -e  'using LiveServer; serve(dir="docs/build")'

Or with python3 using from the docs/build folder using

python3 -m http.server

The generated documentation should now be viewable locally in a browser at http://localhost:8000.