Cristallo is an open-source web-based digital twin operational platform (DTOP). User interaction is currently provided via webforms. This version works best on a standalone machine, and is primarily aimed at demonstrating how this type of digital twin can be applied to a specific engineering application. In this code, the application structure is a 3-storey structure.

Disclaimer: The repository does not include code for recording data, because of the hardware-specific nature of such code. In the spirit of demonstrating the concept, data is either simulated or in some cases pre-recorded experimental data is used.

The DTOP runs on any machine with a modern browser. There are no proprietary barriers preventing users to access the software. This section will guide you through a few main steps to install Cristallo on your machine. Cristallo is powered by Python 3, so before you begin, make sure you have Python 3 installed on your machine.

Best performance with python 3.8+

Download or clone this repository on your local machine. For a visual walkthrough on how to download and run, visit https://www.youtube.com/watch?v=-l04b4dEypo

Skip the following instructions if you are familiar with GitHub.

If you don't have git and a Github account, just click on the code green button at the top of this page and hit Download. This will zip and download the code in your designated downloads folder. Then, open a code editor in the unzipped downloaded folder.

If you have git but not a Github account, or if you don't have Github SSH keys, then clone the repo with:

git clone https://github.com/Digital-Twin-Operational-Platform/Cristallo.git

If you have GitHub SSH keys you know what you are doing and you can move ahead.

Before we install the required dependencies, we need a new virtual environment, i.e. a safe copy of your installed Python distribution.

But why? Python 3 is often used by your machine to perform essential tasks. Creating a virtual environment will prevent installing dependencies that your OS does not need, which can conflict with your computer system (a.k.a. dependency hell). In other words, the Python used by your OS will be fully orthogonal to the Python used in your project.

To create the virtual environment (1) locate the executable of your Python3 system distrubution, and (2) invoke the following CLI command:

python3 -m venv venv 

If your Python3 distribution is not in your PATH, you may need to replace python3 with the full path. For example on Windows:

C:/Users/mda/AppData/Local/Programs/Python/Python39/python.exe -m venv venv 

or on MacOS:

/usr/local/bin/python3 -m venv venv 

This will create the folder venv in your current directory. This folder need not be located inside the downloaded repository.

If you go ahead and create the venv folder in the downloaded repository then make sure it is detached from version control.

From the same directory, invoking the following command will activate the virtual environment:

MacOS/Linux:

source venv/bin/activate

Windows:

venv\Scripts\activate

Successful execution of the above CLI command will result in the prompt displaying the name of the environment venv before the prompt line, as such

MacOS/Linux:

# MacOS/Linux
(venv) cristallo % 
# Windows:
(venv) C:\cristallo> 

There are four main dependencies that need to be installed separately:

1. Flask
2. Scipy
3. Plotly
4. Wtforms

We can install these dependencies by pip install. pip will take care to install all the related dependencies that these packages need in order to function.

(venv) C:\cristallo> pip install flask scipy plotly wtforms

pip install flask will automatically install the following: zipp, MarkupSafe, colorama, Werkzeug, Jinja2, itsdangerous, importlib-metadata, click, flask

pip install scipy will automatically install the following: numpy, scipy

pip install plotly will automatically install the following: six, tenacity, plotly

You can also install all the dependencies in one go with the following CLI command:

(venv) C:\cristallo> pip install -r requirements.txt

In requirements.txt all the individual dependencies are spelled out in a list. This file is a snapshot of the list of dependencies at a particular point in time, i.e. the moment the requirements.txt was created.

At this particular moment (April 2022) the requirements.txt looks as follows:

click==8.1.2
colorama==0.4.4
Flask==2.1.1
importlib-metadata==4.11.3
itsdangerous==2.1.2
Jinja2==3.1.1
MarkupSafe==2.1.1
numpy==1.22.3
plotly==5.7.0
scipy==1.8.0
six==1.16.0
tenacity==8.0.1
Werkzeug==2.1.1
WTForms==3.0.1
zipp==3.8.0

This is how requirements.txt is supposed to look like for the current version of the project.

Using the pip install -r requirements.txt CLI command is only reccommended to install the dependencies if your venv is set up correctly.

Finally, we can give Cristallo a go by starting the Flask server.

# MacOS/Linux:
(venv) cristallo% export FLASK_APP=run.py
(venv) cristallo% export FLASK_DEBUG=1
(venv) cristallo% flask run

# PowerShell (Windows)
(venv) C:\cristallo> $env:FLASK_APP=run.py
(venv) C:\cristallo> $env:FLASK_DEBUG=1
(venv) C:\cristallo> flask run

# Windows:
(venv) C:\cristallo> set FLASK_APP=run.py
(venv) C:\cristallo> set FLASK_DEBUG=1
(venv) C:\cristallo> flask run

The successful excecution of this CLI sequence will start the flask server, which will output the following console message:

 * Serving Flask app 'run.py' (lazy loading)
 * Environment: production
   WARNING: This is a development server. Do not use it in a production deployment.
   Use a production WSGI server instead.
 * Debug mode: on
 * Running on http://127.0.0.1:5000 (Press CTRL+C to quit)
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 169-144-882

Now you can navigate to the URL http://localhost:5000/ via your browser to access the DTOP.

Bonney, M., De Angelis, M., Dal Borgo, M., Andrade, L., Beregi, S., Jamia, N., & Wagg, D. (2022). Development of a digital twin operational platform using Python Flask. Data-Centric Engineering, 3, E1. doi:10.1017/dce.2022.1

@article{bonney_de angelis_dal borgo_andrade_beregi_jamia_wagg_2022, 
title = {Development of a digital twin operational platform using Python Flask},
volume = {3}, 
DOI = {10.1017/dce.2022.1}, 
journal = {Data-Centric Engineering}, 
publisher = {Cambridge University Press}, 
author = {Bonney, Matthew S. and de Angelis, Marco and Dal Borgo, Mattia and Andrade, Luis and Beregi, Sandor and Jamia, Nidhal and Wagg, David J.}, 
year = {2022}, 
pages = {e1}}

Instructions on how to contribute to the project as adeveloper can be consulted via our documentation.

documentation: https://digital-twin-operational-platform.github.io/ github: https://github.com/Digital-Twin-Operational-Platform/Cristallo/