The QAD-API Python library is a library for accessing the (REST) API of QAD Cloud.

As this library serves simply as a Python front-end to the QAD Cloud, you will first need an account on this platform, before using the library.

We do not yet provide a PyPi package. The recommended method for installing QAD-API is to clone the following repository, and then "pip install" it from the appropriate local folder:

git clone https://github.com/HQSquantumsimulations/qad-api.git
pip install -e qad-api

The QAD-API is utilized by importing the class QAD_API from the root package qad_api. In order access the API, one must create an instance of this class.

To learn more about the API functionality, please refer to the documentation of QAD_API.

To get started with the QAD_API, we provide a quick and simple example here. You also find this example in the folder examples/lattice.

We will create an instance of QAD_API, which will authenticate the user with the back-end. The first time this is done, the user will be asked to open a link in a browser and use their credentials to authenticate with the back-end (OAuth2).

After this, we use the instance of QAD_API to access the API functionality. We create a unit-cell and a system for the lattice-based problem solver "SCCE," and also create a job for that solver by passing the recently created handlers, then wait for the job to finish. This will take some time, after which we download the results file to the local file system.

from qad_api import QAD_API

# Creating an QAD_API instance will authenticate the user with the backend
qad = QAD_API()

# Create a unit-cell
unit_cell = qad.lattice.unit_cells.create('1D XXZ', {
    "unitcell": {
        "atoms": [ #                     eps    U
            ['0', 'A', [   0, 0, 0],  0.0001, 0.0 ],
            ['1', 'B', [ 0.5, 0, 0], -0.0001, 0.0 ] 
        ],
        "bonds": [ #                 t    U
            ['0', '0', [1, 0, 0], -1.0, 0.0]
        ],
        "lattice_vectors": [
            [1, 0, 0]
        ]
    }
})
print(f"Unit cell created: {unit_cell.id}")

# Create a system
system = qad.lattice.systems.create('1D XXZ', {
    "system": {
        "cluster_size":    [14, 1, 1],   # measured in unit cells
        "system_size":     [ 2, 1, 1],   # measured in clusters
        "cluster_offset":  [ 0, 0, 0],   # measured in clusters
        "system_boundary_condition": "periodic"
    }
})
print(f"System created: {system.id}")

# Create a job (will start to run it automatically)
job = qad.lattice.scce.jobs.create('1D XXZ', unit_cell, system)
print(f"Job created: {job.id}")

# Wait for the job to be done (when using co-routines: await job.wait())
job.wait_blocking()

# Download the result to a local file
job.download_result(f"./{job.id}.h5")
print("Downloaded result")