Skip to main content
Pre-release

This release is a pre-release and may not be stable for production use.

Tesseract Decoder

A Search-Based Decoder for Quantum Error Correction.

Licensed under the Apache 2.0 open-source license C++

Installation – Usage – Python Interface – Paper – Help – Citation – Contact

Tesseract is a Most Likely Error decoder designed for Low Density Parity Check (LDPC) quantum error-correcting codes. It applies pruning heuristics and manifold orientation techniques during a search over the error subsets to identify the most likely error configuration consistent with the observed syndrome. Tesseract achieves significant speed improvements over traditional integer programming-based decoders while maintaining comparable accuracy at moderate physical error rates.

We tested the Tesseract decoder for:

  • Surface codes
  • Color codes
  • Bivariate-bicycle codes
  • Transversal CNOT protocols for surface codes

Features

  • A* search: deploys A* search while running a Dijkstra algorithm with early stop for high performance.
  • Stim and DEM Support: processes Stim circuit files and Detector Error Model (DEM) files with arbitrary error models. Zero-probability error instructions are automatically removed when a DEM is loaded.
  • Parallel Decoding: uses multithreading to accelerate the decoding process, making it suitable for large-scale simulations.
  • Efficient Beam Search: implements a beam search algorithm to minimize decoding cost and enhance efficiency. Sampling and Shot Range Processing: supports sampling shots from circuits. When a detection error model is provided without an accompanying circuit, Tesseract requires detection events from files using --in. The decoder can also process specific shot ranges for flexible experiment setups.
  • Detailed Statistics: provides comprehensive statistics output, including shot counts, error counts, and processing times.
  • Heuristics: includes flexible heuristic options: --beam, --det-penalty, --beam-climbing, --no-revisit-dets, --at-most-two-errors-per-detector, and --pqlimit to improve performance while maintaining a low logical error rate. To learn more about these options, use ./bazel-bin/src/tesseract --help
  • Visualization tool: open the viz directory in your browser to view decoding results. See viz/README.md for instructions on generating the visualization JSON.

Installation

Tesseract relies on the following external libraries:

  • argparse: For command-line argument parsing.
  • nlohmann/json: For JSON handling (used for statistics output).
  • Stim: For quantum circuit simulation and error model handling.

Build Instructions

Tesseract uses Bazel as its build system. To build the decoder:

bazel build src:all

Running Tests

Unit tests are executed with Bazel. Run the quick test suite using:

bazel test //src:all

By default the tests use reduced parameters and finish in under 30 seconds. To run a more exhaustive suite with additional shots and larger distances, set:

TESSERACT_LONG_TESTS=1 bazel test //src:all

Usage

The file tesseract_main.cc provides the main entry point for Tesseract Decoder. It can decode error events from Stim circuits, DEM files, and pre-existing detection event files.

Basic Usage:

./tesseract --circuit CIRCUIT_FILE.stim --sample-num-shots N --print-stats

To decode pre-generated detection events, provide the input file using --in SHOTS_FILE --in-format FORMAT.

Example with Advanced Options:

./tesseract \
        --pqlimit 1000000 \
        --at-most-two-errors-per-detector \
        --det-order-seed 232852747 \
        --circuit circuit_file.stim \
        --sample-seed 232856747 \
        --sample-num-shots 10000 \
        --threads 32 \
        --print-stats \
        --beam 23 \
        --num-det-orders 1 \
        --shot-range-begin 582 \
        --shot-range-end 583

Example Usage

Sampling Shots from a Circuit:

./tesseract --circuit surface_code.stim --sample-num-shots 1000 --out predictions.01 --out-format 01

Using a Detection Event File:

./tesseract --in events.01 --in-format 01 --dem surface_code.dem --out decoded.txt

Using a Detection Event File and Observable Flips:

./tesseract --in events.01 --in-format 01 --obs_in obs.01 --obs-in-format 01 --dem surface_code.dem --out decoded.txt

Tesseract supports reading and writing from all of Stim's standard output formats.

Performance Optimization

Here are some tips for improving performance:

  • Parallelism over shots: increase --threads to leverage multicore processors for faster decoding.
  • Beam Search: use --beam to control the trade-off between accuracy and speed. Smaller beam sizes result in faster decoding but potentially lower accuracy.
  • Beam Climbing: enable --beam-climbing for enhanced cost-based decoding.
  • At most two errors per detector: enable --at-most-two-errors-per-detector to improve performance.
  • Priority Queue limit: use --pqlimit to limit the size of the priority queue.

Output Formats

  • Observable flips output: predictions of logical errors.
  • DEM usage frequency output: if --dem-out is specified, outputs estimated error frequencies.
  • Statistics output: includes number of shots, errors, low confidence shots, and processing time.

Python Interface

Full Python wrapper documentation

This repository contains the C++ implementation of the Tesseract quantum error correction decoder, along with a Python wrapper. The Python wrapper/interface exposes the decoding algorithms and helper utilities, allowing Python users to leverage this high-performance decoding algorithm.

The following example demonstrates how to create and use the Tesseract decoder using the Python interface.

from tesseract_decoder import tesseract
import stim
import numpy as np


# 1. Define a detector error model (DEM)
dem = stim.DetectorErrorModel("""
    error(0.1) D0 D1 L0
    error(0.2) D1 D2 L1
    detector(0, 0, 0) D0
    detector(1, 0, 0) D1
    detector(2, 0, 0) D2
""")

# 2. Create the decoder configuration
config = tesseract.TesseractConfig(dem=dem, det_beam=50)

# 3. Create a decoder instance
decoder = config.compile_decoder()

# 4. Simulate detection events
syndrome = [0, 1, 1]

# 5a. Decode to observables
flipped_observables = decoder.decode(syndrome)
print(f"Flipped observables: {flipped_observables}")

# 5b. Alternatively, decode to errors
decoder.decode_to_errors(np.where(syndrome)[0])
predicted_errors = decoder.predicted_errors_buffer
# Indices of predicted errors
print(f"Predicted errors indices: {predicted_errors}")
# Print properties of predicted errors
for i in predicted_errors:
    print(f"    {i}: {decoder.errors[i]}")

Help

We are committed to providing a friendly, safe, and welcoming environment for all. Please read and respect our Code of Conduct.

Citation

When publishing articles or otherwise writing about Tesseract Decoder, please cite the following:

@misc{beni2025tesseractdecoder,
    title={Tesseract: A Search-Based Decoder for Quantum Error Correction},
    author = {Aghababaie Beni, Laleh and Higgott, Oscar and Shutty, Noah},
    year={2025},
    eprint={2503.10988},
    archivePrefix={arXiv},
    primaryClass={quant-ph},
    doi = {10.48550/arXiv.2503.10988},
    url={https://arxiv.org/abs/2503.10988},
}

Contact

For any questions or concerns not addressed here, please email tesseract-decoder-dev@google.com.

Disclaimer

Tesseract Decoder is not an officially supported Google product. This project is not eligible for the Google Open Source Software Vulnerability Rewards Program.

Copyright 2025 Google LLC.

Metadata

Release files for tesseract-decoder 0.1.1.dev20250812140327

For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.

Built distributions (wheels)

Table of built distributions (wheels) for tesseract-decoder 0.1.1.dev20250812140327
File
tesseract_decoder-0.1.1.dev20250812140327-py312-none-manylinux_2_39_x86_64.manylinux2014_x86_64.whl Python 3.12 none Linux glibc 2.39+ x86-64, Linux glibc 2.17+ x86-64 Details
tesseract_decoder-0.1.1.dev20250812140327-py312-none-manylinux_2_35_x86_64.manylinux2014_x86_64.whl Python 3.12 none Linux glibc 2.35+ x86-64, Linux glibc 2.17+ x86-64 Details
tesseract_decoder-0.1.1.dev20250812140327-py312-none-macosx_11_0_arm64.whl Python 3.12 none macOS 11.0+ ARM64 Details
tesseract_decoder-0.1.1.dev20250812140327-py312-none-macosx_10_13_x86_64.whl Python 3.12 none macOS 10.13+ x86-64 Details
tesseract_decoder-0.1.1.dev20250812140327-py311-none-manylinux_2_39_x86_64.manylinux2014_x86_64.whl Python 3.11 none Linux glibc 2.39+ x86-64, Linux glibc 2.17+ x86-64 Details
tesseract_decoder-0.1.1.dev20250812140327-py311-none-manylinux_2_35_x86_64.manylinux2014_x86_64.whl Python 3.11 none Linux glibc 2.17+ x86-64, Linux glibc 2.35+ x86-64 Details
tesseract_decoder-0.1.1.dev20250812140327-py311-none-macosx_11_0_arm64.whl Python 3.11 none macOS 11.0+ ARM64 Details
tesseract_decoder-0.1.1.dev20250812140327-py311-none-macosx_10_13_x86_64.whl Python 3.11 none macOS 10.13+ x86-64 Details
tesseract_decoder-0.1.1.dev20250812140327-py310-none-manylinux_2_39_x86_64.manylinux2014_x86_64.whl Python 3.10 none Linux glibc 2.39+ x86-64, Linux glibc 2.17+ x86-64 Details
tesseract_decoder-0.1.1.dev20250812140327-py310-none-manylinux_2_35_x86_64.manylinux2014_x86_64.whl Python 3.10 none Linux glibc 2.17+ x86-64, Linux glibc 2.35+ x86-64 Details
tesseract_decoder-0.1.1.dev20250812140327-py310-none-macosx_11_0_arm64.whl Python 3.10 none macOS 11.0+ ARM64 Details
tesseract_decoder-0.1.1.dev20250812140327-py310-none-macosx_10_13_x86_64.whl Python 3.10 none macOS 10.13+ x86-64 Details

Total release size: 39.1 MB

Release files / tesseract_decoder-0.1.1.dev20250812140327-py312-none-manylinux_2_39_x86_64.manylinux2014_x86_64.whl

Download URL tesseract_decoder-0.1.1.dev20250812140327-py312-none-manylinux_2_39_x86_64.manylinux2014_x86_64.whl
Size 3.4 MB
Tags Linux glibc 2.17+ x86-64 Linux glibc 2.39+ x86-64 Python 3.12
SHA-256 checksum
How to use checksums
06bf242813685021b874967724b1da112c1aa8280c72184897de507c4a2030bb
BLAKE2b-256 checksum
How to use checksums
da1943452e7ab9ffcef457278b86d0f4d9ed2c7fa1ef9340f807e97ceb2aff56
Upload date
Uploaded using Trusted Publishing?
What is trusted publishing?
No
Uploaded via twine/6.1.0 CPython/3.9.23

Release files / tesseract_decoder-0.1.1.dev20250812140327-py312-none-manylinux_2_35_x86_64.manylinux2014_x86_64.whl

Download URL tesseract_decoder-0.1.1.dev20250812140327-py312-none-manylinux_2_35_x86_64.manylinux2014_x86_64.whl
Size 3.5 MB
Tags Linux glibc 2.17+ x86-64 Linux glibc 2.35+ x86-64 Python 3.12
SHA-256 checksum
How to use checksums
6f3f8f96c3da481c136db24b11e215a5862b871775875d4460111cd9963d4b03
BLAKE2b-256 checksum
How to use checksums
f3f0c0187a2e84e3e2c13988a97beed40eee311613f8b16af655b1693f7de953
Upload date
Uploaded using Trusted Publishing?
What is trusted publishing?
No
Uploaded via twine/6.1.0 CPython/3.9.23

Release files / tesseract_decoder-0.1.1.dev20250812140327-py312-none-macosx_11_0_arm64.whl

Download URL tesseract_decoder-0.1.1.dev20250812140327-py312-none-macosx_11_0_arm64.whl
Size 3.1 MB
Tags Python 3.12 macOS 11.0+ ARM64
SHA-256 checksum
How to use checksums
0dd66eb8926d6945b7c82382701b3ea994da398f1b2c614dd0f6336619efcdfc
BLAKE2b-256 checksum
How to use checksums
0aff68c63c2bd746db45b1a8013eb8424895d06fa9e374016e5b7cf30e3992ac
Upload date
Uploaded using Trusted Publishing?
What is trusted publishing?
No
Uploaded via twine/6.1.0 CPython/3.9.23

Release files / tesseract_decoder-0.1.1.dev20250812140327-py312-none-macosx_10_13_x86_64.whl

Download URL tesseract_decoder-0.1.1.dev20250812140327-py312-none-macosx_10_13_x86_64.whl
Size 3.0 MB
Tags Python 3.12 macOS 10.13+ x86-64
SHA-256 checksum
How to use checksums
285dd0ea504c296bede79c13e66f37cbc4e4760faa24983bd1c64fc032c8e3a3
BLAKE2b-256 checksum
How to use checksums
0dc74228bf2451ed4ecdc669d02e129d2e351d0d4c5d745a3d77f63fb927f722
Upload date
Uploaded using Trusted Publishing?
What is trusted publishing?
No
Uploaded via twine/6.1.0 CPython/3.9.23

Release files / tesseract_decoder-0.1.1.dev20250812140327-py311-none-manylinux_2_39_x86_64.manylinux2014_x86_64.whl

Download URL tesseract_decoder-0.1.1.dev20250812140327-py311-none-manylinux_2_39_x86_64.manylinux2014_x86_64.whl
Size 3.4 MB
Tags Linux glibc 2.17+ x86-64 Linux glibc 2.39+ x86-64 Python 3.11
SHA-256 checksum
How to use checksums
807698ebdc02cbecf8905adb3985c6bc5bb8d784f980550f0fc1ac90d492ee94
BLAKE2b-256 checksum
How to use checksums
588b1ffc9b778a4e6285e6af6d9e8a268832ac82f62587bd8ec374e133972670
Upload date
Uploaded using Trusted Publishing?
What is trusted publishing?
No
Uploaded via twine/6.1.0 CPython/3.9.23

Release files / tesseract_decoder-0.1.1.dev20250812140327-py311-none-manylinux_2_35_x86_64.manylinux2014_x86_64.whl

Download URL tesseract_decoder-0.1.1.dev20250812140327-py311-none-manylinux_2_35_x86_64.manylinux2014_x86_64.whl
Size 3.5 MB
Tags Linux glibc 2.17+ x86-64 Linux glibc 2.35+ x86-64 Python 3.11
SHA-256 checksum
How to use checksums
ea9146814de2010e381001d2ddc8d32e0d4aa8edc76804e17f9efe7baee7ad1d
BLAKE2b-256 checksum
How to use checksums
c345c6b2c87dc01f3e07e3df1c007a7f932a29b2d8db73543e80e494f72ab1a5
Upload date
Uploaded using Trusted Publishing?
What is trusted publishing?
No
Uploaded via twine/6.1.0 CPython/3.9.23

Release files / tesseract_decoder-0.1.1.dev20250812140327-py311-none-macosx_11_0_arm64.whl

Download URL tesseract_decoder-0.1.1.dev20250812140327-py311-none-macosx_11_0_arm64.whl
Size 3.1 MB
Tags Python 3.11 macOS 11.0+ ARM64
SHA-256 checksum
How to use checksums
36751bc00c51849e2d9686f08cd407cb1a59b429f432029306fa8548e27786f9
BLAKE2b-256 checksum
How to use checksums
749c435e9b9880b53cdf1a2ea8302a3bb14003b4bd1168709bc222711ceb3024
Upload date
Uploaded using Trusted Publishing?
What is trusted publishing?
No
Uploaded via twine/6.1.0 CPython/3.9.23

Release files / tesseract_decoder-0.1.1.dev20250812140327-py311-none-macosx_10_13_x86_64.whl

Download URL tesseract_decoder-0.1.1.dev20250812140327-py311-none-macosx_10_13_x86_64.whl
Size 3.0 MB
Tags Python 3.11 macOS 10.13+ x86-64
SHA-256 checksum
How to use checksums
081e42b7e6a4d3941b594cf1beebb8d9dc847694374e02d8719613c9077a22d4
BLAKE2b-256 checksum
How to use checksums
28548555d9cff0ab83728edeeea9b86dff11e79119c6ed6b6c76b2660d92ef57
Upload date
Uploaded using Trusted Publishing?
What is trusted publishing?
No
Uploaded via twine/6.1.0 CPython/3.9.23

Release files / tesseract_decoder-0.1.1.dev20250812140327-py310-none-manylinux_2_39_x86_64.manylinux2014_x86_64.whl

Download URL tesseract_decoder-0.1.1.dev20250812140327-py310-none-manylinux_2_39_x86_64.manylinux2014_x86_64.whl
Size 3.4 MB
Tags Linux glibc 2.17+ x86-64 Linux glibc 2.39+ x86-64 Python 3.10
SHA-256 checksum
How to use checksums
26a06471ebfc9e671ecb32500fd86130d6f979183320b360b7587e08b770752e
BLAKE2b-256 checksum
How to use checksums
588ddd4459b2e8103d7816d9522d7f84d979d48a52f075b5c357a45669eb829f
Upload date
Uploaded using Trusted Publishing?
What is trusted publishing?
No
Uploaded via twine/6.1.0 CPython/3.9.23

Release files / tesseract_decoder-0.1.1.dev20250812140327-py310-none-manylinux_2_35_x86_64.manylinux2014_x86_64.whl

Download URL tesseract_decoder-0.1.1.dev20250812140327-py310-none-manylinux_2_35_x86_64.manylinux2014_x86_64.whl
Size 3.5 MB
Tags Linux glibc 2.17+ x86-64 Linux glibc 2.35+ x86-64 Python 3.10
SHA-256 checksum
How to use checksums
81c1e27cb56f114211ddebcef8779910baab0d5409453ff1302aa3bf1c2eec19
BLAKE2b-256 checksum
How to use checksums
a49a2bcf9738c410989e7e49a748f4ea1548dfea1e1495619c169fad7f8b4082
Upload date
Uploaded using Trusted Publishing?
What is trusted publishing?
No
Uploaded via twine/6.1.0 CPython/3.9.23

Release files / tesseract_decoder-0.1.1.dev20250812140327-py310-none-macosx_11_0_arm64.whl

Download URL tesseract_decoder-0.1.1.dev20250812140327-py310-none-macosx_11_0_arm64.whl
Size 3.1 MB
Tags Python 3.10 macOS 11.0+ ARM64
SHA-256 checksum
How to use checksums
375c786e3fc71c4de74fe58521b46d57fca4a272cdbf70455dfbf1102c088476
BLAKE2b-256 checksum
How to use checksums
633a8c7c2e24be627db790b1b2cc775c754342f622f302730e8b34b332e5f3db
Upload date
Uploaded using Trusted Publishing?
What is trusted publishing?
No
Uploaded via twine/6.1.0 CPython/3.9.23

Release files / tesseract_decoder-0.1.1.dev20250812140327-py310-none-macosx_10_13_x86_64.whl

Download URL tesseract_decoder-0.1.1.dev20250812140327-py310-none-macosx_10_13_x86_64.whl
Size 3.0 MB
Tags Python 3.10 macOS 10.13+ x86-64
SHA-256 checksum
How to use checksums
356e9c82f60aa8b12658096364e76e830f52bb28d53e53e94360287307c55773
BLAKE2b-256 checksum
How to use checksums
d1f125dd3c0a19801f64fede31ed20fca155399734c071992b5786eec3e9a5ed
Upload date
Uploaded using Trusted Publishing?
What is trusted publishing?
No
Uploaded via twine/6.1.0 CPython/3.9.23

Release history Release notifications | RSS feed

This release
Anthropic, PBC Visionary sponsor Bloomberg Visionary sponsor Hudson River Trading Visionary sponsor Meta Visionary sponsor NVIDIA Visionary sponsor Microsoft Sustainability sponsor Depot Continuous Integration AWS Cloud computing and Security Sponsor Datadog Monitoring Fastly CDN Google Download Analytics Sentry Error logging StatusPage Status page