This repository host the work I done with QISKit during my Master's thesis. I shared the code according to the CeCILL-B license (see the license file).

Installation

The installation procedure is not really standard and will be changed when I will have the time. At the moment, you need to clone the repository in a folder called utils because all the imports in the code assume that the folder is called utils. Then you need to update your PYTHONPATH. The procedure is summarised below:

1. Clone the repository as utils:

git clone https://github.com/nelimee/quantum-tools.git utils

2. Update your PYTHONPATH to point to the parent folder of utils:

export PYTHONPATH="/parent/folder/of/utils/:${PYTHONPATH}"

Instead of updating the PYTHONPATH at each login, you can add the previous line to your .bashrc:

echo 'export PYTHONPATH="/parent/folder/of/utils/:${PYTHONPATH}"' >> ~/.bashrc

Directory structure

HHL folder

As its name indicates, this folder is dedicated to scripts related to the HHL algorithm. In this folder you have:

1. 4x4_system.py: An implementation of the HHL algorithm for a 4x4 matrix. The implementation is based on Quantum Circuit Design for Solving Linear Systems of Equations (v2) but corrects some errors in the original paper.
2. hamiltonian_error.py: A script that will compute the errors in the Hamiltonian simulation procedure and that will output useful information on them. The error is the norm of the difference between the simulated matrix and the "exact" matrix (up to floating-point errors in the numerical methods used).
3. hamiltonian_unitary_test.py: A convenient script that I used to verify the validity of the different steps of HHL by computing the error between the expected unitary matrix and the simulated one. The script has not been formatted to be user-friendly.
4. optim_hamil.py: A script used to compute the best coefficients for the powers of the Hamiltonian simulation procedure. As written in the comments, there is no proof of "why it works?", but the Hamiltonian powers are simulated with a really low error.
5. test.py: A scratch file that contains an example of the usage of the qiskit.extensions.quantum_initializer._initializer.initialize function.

error_analysis folder

This folder links to an other git repository that contains helpers to estimate the errors due to the physical imprecisions of the quantum chips. The code is still draft and does not work as expected for the moment.

gates folder

Each file in this folder declare some personalised quantum gates.

visualisation folder

This folder links to an other git repository: qasm2image.

Usage

The module is installed under the name utils. You can import the qpe gate using

import utils.gates.qpe

You can also launch the scripts in HHL/