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An open source quantum circuit simulator to be run locally with the Amazon Braket SDK

Project description

Amazon Braket Default Simulator

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The Amazon Braket Default Simulator is a Python open source library that provides an implementation of a quantum simulator that you can run locally. You can use the simulator to test quantum tasks that you construct for the Amazon Braket SDK before you submit them to the Amazon Braket service for execution.

Setting up Amazon Braket Default Simulator Python

You must have the Amazon Braket SDK installed to use the local simulator. Follow the instructions in the README for setup.

Checking the version of the default simulator

You can check your currently installed version of amazon-braket-default-simulator with pip show:

pip show amazon-braket-default-simulator

or alternatively from within Python:

>>> from braket import default_simulator
>>> default_simulator.__version__


The quantum simulator implementations StateVectorSimulator and DensityMatrixSimulator plug into the LocalSimulator interface in Amazon Braket SDK, with the backend parameters as "braket_sv" and "braket_dm", respectively. Alternatively, to use StateVectorSimulator, you can instantiate LocalSimulator with no arguments or with backend="default":

Executing a circuit using the default simulator

from braket.circuits import Circuit
from braket.devices import LocalSimulator

device = LocalSimulator()

bell = Circuit().h(0).cnot(0, 1)
print(, shots=100).result().measurement_counts)


Detailed documentation, including the API reference, can be found on Read the Docs

To generate the API Reference HTML in your local environment

First, install tox:

pip install tox

To generate the HTML, first change directories (cd) to position the cursor in the amazon-braket-default-simulator-python directory. Then, run the following command to generate the HTML documentation files:

tox -e docs

To view the generated documentation, open the following file in a browser: ../amazon-braket-default-simulator-python/build/documentation/html/index.html


If you want to contribute to the project, be sure to run unit tests and get a successful result before you submit a pull request. To run the unit tests, first install the test dependencies using the following command:

pip install -e "amazon-braket-default-simulator-python[test]"

To run the unit tests:

tox -e unit-tests

You can also pass in various pytest arguments to run selected tests:

tox -e unit-tests -- your-arguments

For more information, please see pytest usage.

To run linters and doc generators and unit tests:


To run the performance tests:

tox -e performance-tests

These tests will compare the performance of a series of simulator executions for your changes against the latest commit on the main branch. Note: The execution times for the performance tests are affected by the other processes running on the system. In order to get stable results, stop other applications when running these tests.


This project is licensed under the Apache-2.0 License.

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