QXTools

QXTools is a Julia package for simulating quantum circuits using tensor networking approaches. It targets large distributed memory clusters with hardware accelerators. It was developed as part of the QuantEx project, one of the individual software projects of WP8 of PRACE 6IP.

QXTools depends on a number of other Julia packages developed that were also developed as part of the QuantEx project. These include QXZoo which is capable of generating and manipulating quantum circuits, QXTns which features data structures and functions for manipulating tensor networks, QXGraphDecompositions which implements a number of graph algorithms for finding good contraction plans and QXContexts which is designed to run on large distributed clusters.

Documentation can be found here.

The design and implementation of QXTools and related packages was inspired by many other frameworks and packages including ITensors.jl, TensorOperations.jl, Yao.jl, TAL-SH and ExaTN.

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

import Pkg
Pkg.add("QXTools")

An example of how QXTools can be used to calculate a set of amplitudes for small GHZ preparation circuit looks like

using QXTools
using QXTools.Circuits

# Create ghz circuit
circ = create_ghz_circuit(3)

# Convert the circuit to a tensor network circuit
tnc = convert_to_tnc(circ)

# Find a good contraction plan
plan = flow_cutter_contraction_plan(tnc; time=10)

# Contract the network using this plan to find the given amplitude for different outputs
@show QXTools.single_amplitude(tnc, plan, "000")
@show QXTools.single_amplitude(tnc, plan, "111")
@show QXTools.single_amplitude(tnc, plan, "100")

This is only recommended for small test cases. For larger scale runs one can call the generate_simulation_files which will do the conversion to a network, find the contraction plan and create output files describing the required calculations. For example

using QXTools
using QXTools.Circuits

# Create ghz circuit
circ = create_ghz_circuit(3)

generate_simulation_files(circ, "ghz_3", time=10)

will generate the files:

• ghz_3.qx: A DSL file with instructions
• ghz_3.jld2: A data file with initial tensors
• ghz_3.yml: A parameter file with parameters controlling the simulation

These can be used as input to QXContexts to run the simulation on distributed clusters. For more details and options see the documentation at docs.

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.

QXTools.jl using Documenter.jl to generate documentation. To build the documentation locally run the following from the docs folder.

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

julia --project -e 'import Pkg; Pkg.instantiate()'

and then to build the documentation

julia --project make.jl

To serve the generated documentation locally use

julia --project -e 'using LiveServer; serve(dir="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.