sinter 1.9.dev1648802898

Samples stim circuits and decodes them using pymatching.

sinter: stim sampling helper

sinter is a bit of glue code that allows using Stim and a decoder in tandem in order to benchmark quantum error correction circuits using Monte Carlo sampling. sinter supports using pymatching to decode the samples, and can use python multiprocessing to fully utilize a computer's resources to get good performance.

sinter is still in development. Its API and output formats are not stable.

How to Install

Sinter is available as a pypi package. It can be installed using pip:

pip install sinter

How to Use: Python API

This example assumes you are in a python environment with stim and sinter installed.

import stim
import sinter


# Generates surface code circuit tasks using Stim's circuit generation.
def generate_example_tasks():
    for p in [0.001, 0.005, 0.01]:
        for d in [3, 5]:
            yield sinter.Task(
                circuit=stim.Circuit.generated(
                    rounds=d,
                    distance=d,
                    after_clifford_depolarization=p,
                    code_task=f'surface_code:rotated_memory_x',
                ),
                json_metadata={
                    'p': p,
                    'd': d,
                },
            )


def main():
    # Collect the samples (takes a few minutes).
    samples = sinter.collect(
        num_workers=4,
        max_shots=1_000_000,
        max_errors=1000,
        tasks=generate_example_tasks(),
        decoders=['pymatching'],
    )

    # Print as CSV data.
    print(sinter.CSV_HEADER)
    for sample in samples:
        print(sample.to_csv_line())

    # Render a matplotlib plot of the data into a png image.
    fig, axs = sinter.plot(
        samples=samples,
        x_func=lambda e: e.json_metadata['p'],
        xaxis='[log]Physical Error Rate',
        group_func=lambda e: f"Rotated Surface Code d={e.json_metadata['d']}",
    )
    fig.savefig('plot.png')


# NOTE: This is actually necessary! If the code inside 'main()' was at the
# module level, the multiprocessing children spawned by sinter.collect would
# also attempt to run that code.
if __name__ == '__main__':
    main()

Example output to stdout:

     shots,    errors,  discards, seconds,decoder,strong_id,json_metadata
   1000000,       837,         0,    36.6,pymatching,9f7e20c54fec45b6aef7491b774dd5c0a3b9a005aa82faf5b9c051d6e40d60a9,"{""d"":3,""p"":0.001}"
     53498,      1099,         0,    6.52,pymatching,3f40432443a99b933fb548b831fb54e7e245d9d73a35c03ea5a2fb2ce270f8c8,"{""d"":3,""p"":0.005}"
     16269,      1023,         0,    3.23,pymatching,17b2e0c99560d20307204494ac50e31b33e50721b4ebae99d9e3577ae7248874,"{""d"":3,""p"":0.01}"
   1000000,       151,         0,    77.3,pymatching,e179a18739201250371ffaae0197d8fa19d26b58dfc2942f9f1c85568645387a,"{""d"":5,""p"":0.001}"
     11363,      1068,         0,    12.5,pymatching,a4dec28934a033215ff1389651a26114ecc22016a6e122008830cf7dd04ba5ad,"{""d"":5,""p"":0.01}"
     61569,      1001,         0,    24.5,pymatching,2fefcc356752482fb4c6d912c228f6d18762f5752796c668b6abeb7775f5de92,"{""d"":5,""p"":0.005}"

and the corresponding image saved to plot.png:

How to Use: Linux Command Line

This example assumes you are using a linux command line in a python virtualenv with sinter installed.

pick circuits

For this example, we will use Stim's circuit generation functionality to produce circuits to benchmark. We will make rotated surface code circuits with various physical error rates, with filenames like rotated_d5_p0.001_surface_code.stim.

mkdir -p circuits
python -c "

import stim

for p in [0.001, 0.005, 0.01]:
    for d in [3, 5]:
        with open(f'circuits/rotated_d{d}_p{p}_surface_code.stim', 'w') as f:
            c = stim.Circuit.generated(
                rounds=d,
                distance=d,
                after_clifford_depolarization=p,
                after_reset_flip_probability=p,
                before_measure_flip_probability=p,
                before_round_data_depolarization=p,
                code_task=f'surface_code:rotated_memory_x')
            print(c, file=f)

"

Normally, making the circuit files is the hardest step, because they are what specifies the problem you are sampling from. Almost all of the work you do will generally involve creating the exact perfect circuit file for your needs. But this is just an example, so we'll use normal surface code circuits.

collect

You can use sinter to collect statistics on each circuit by using the sinter collect command. This command takes options specifying how much data to collect, how to do decoding, etc.

By default, sinter writes the collected statistics to stdout as CSV data. One particularly important option that changes this behavior is -save_resume_filepath, which allows the command to be interrupted and restarted without losing data. Any data already at the file specified by -save_resume_filepath will count towards the amount of statistics asked to be collected, and sinter will append new statistics to this file instead of overwriting it.

sinter collect \
    -processes 4 \
    -circuits circuits/*.stim \
    -metadata_func "(v := path.split('/')[-1].split('_')) and {
        'd': int(v[1][1:]),
        'p': float(v[2][1:])
    }" \
    -decoders pymatching \
    -max_shots 1_000_000 \
    -max_errors 1000 \
    -save_resume_filepath stats.csv

Beware that if you SIGKILL or SIGTEM sinter, instead of just using SIGINT, it's possible (though unlikely) that you are killing it just as it writes a row of CSV data. This truncates the data, which requires manual intervention on your part to fix (e.g. by deleting the partial row using a text editor).

combine

Note that the CSV data written by sinter will contain multiple rows for each case, because sinter starts by running small batches to see roughly what the error rate is before moving to larger batch sizes.

You can get a single-row-per-case CSV file by using sinter combine:

sinter combine stats.csv

     shots,    errors,  discards, seconds,decoder,strong_id,json_metadata
   1000000,       837,         0,    36.6,pymatching,9f7e20c54fec45b6aef7491b774dd5c0a3b9a005aa82faf5b9c051d6e40d60a9,"{""d"":3,""p"":0.001}"
     53498,      1099,         0,    6.52,pymatching,3f40432443a99b933fb548b831fb54e7e245d9d73a35c03ea5a2fb2ce270f8c8,"{""d"":3,""p"":0.005}"
     16269,      1023,         0,    3.23,pymatching,17b2e0c99560d20307204494ac50e31b33e50721b4ebae99d9e3577ae7248874,"{""d"":3,""p"":0.01}"
   1000000,       151,         0,    77.3,pymatching,e179a18739201250371ffaae0197d8fa19d26b58dfc2942f9f1c85568645387a,"{""d"":5,""p"":0.001}"
     11363,      1068,         0,    12.5,pymatching,a4dec28934a033215ff1389651a26114ecc22016a6e122008830cf7dd04ba5ad,"{""d"":5,""p"":0.01}"
     61569,      1001,         0,    24.5,pymatching,2fefcc356752482fb4c6d912c228f6d18762f5752796c668b6abeb7775f5de92,"{""d"":5,""p"":0.005}"

plot

You can use sinter plot to view the results you've collected. This command takes a CSV file, and also some command indicating how to group each case into single curves and also what the desired X coordinate of a case is. This is done in a flexible but very hacky way, by specifying a python expression using the case's filename:

sinter plot \
    -in stats.csv \
    -group_func "'Rotated Surface Code d=' + str(metadata['d'])" \
    -x_func "metadata['p']" \
    -fig_size 1024 1024 \
    -xaxis "[log]Physical Error Rate" \
    -out surface_code_figure.png \
    -show

Which will save a png image of, and also open a window showing, a plot like this one: