pytauargus

Statistical disclosure control (SDC) for tabular data, as a Python package and a headless tauargus command. Protect tables directly from DataFrames with protect(), or run supported legacy Tau-Argus .arb batches without the GUI. The 4.1 manual is the batch/file-format reference, not a complete feature compatibility guarantee. The engine solves with the open-source HiGHS solver. Part of tauargus-engine.

Supported workflows and validation

• OPT, MOD and RND are implemented and regression-tested.
• CKM has a dispatch path, but no dedicated end-to-end CKM regression suite.
• GH, NET and CTA are rejected by the headless engine, even though the parser/generators accept their legacy syntax.
• Suppression audit runs in-process and has known-interval contract tests.

Regression tests do not establish comprehensive numerical equivalence with original Tau-Argus. Compare protection requirements, realised audit intervals, information loss and failure behaviour on representative tables before adopting a workflow; solver changes can produce different valid suppression patterns. Audit is explicit: engine.audit(tab) checks the supplied table's suppression constraints. TableResult.safe() masks cells; it does not run the audit.

Run independent jobs in separate processes and working/output directories. The native solver retains process-global state, and concurrent engine calls in the same process are not validated. OPT/MOD limits are in minutes (0: no limit); the positive-limit tests do not cover deadline expiry or partial results.

See Compatibility and validation for the project scope and the distinction between diagnostics and publication.

Install

pip install --upgrade pytauargus
tauargus --version

These commands install the current release. To keep a specific version, use pytauargus==<version> from PyPI.

Wheels bundle HiGHS and the native engine; no other installation is needed. Available for Python 3.10-3.13 on macOS arm64, Linux x86_64 and aarch64 (manylinux_2_28) and Windows x64. Other platforms: build from source (see the repository).

Cloud native

It runs unattended in containers, CI and batch services:

• Headless: no GUI, no display, no interactive prompts.
• Self-contained: one pip install; the solver (HiGHS) and native libraries are bundled in the wheel. No licensed solver, license server, system packages or Windows registry.
• Stateless: input and output are plain files in the working directory; scratch files go to the system temp directory.
• Scriptable: success is exit code 0; errors go to stderr with a non-zero exit code.
• Portable: wheels for Linux (manylinux_2_28, so any glibc 2.28+ image such as python:3.x-slim), macOS arm64 and Windows x64.

A ready-made image is published to GitHub Container Registry with each release (linux/amd64 and linux/arm64):

docker run --pull=always --rm -v "$PWD":/work ghcr.io/trygu/tauargus-engine:latest run batch.arb

latest is updated with each release; --pull=always checks for an updated image before running. To keep a specific release, choose a version from Releases and use ghcr.io/trygu/tauargus-engine:<version> (without the release tag's py-v prefix).

To build your own image:

FROM python:3.12-slim
RUN pip install --no-cache-dir pytauargus
WORKDIR /work
ENTRYPOINT ["tauargus"]

What problem it solves

Publishing a table can disclose information about individual respondents: a cell with few contributors, or one dominated by a single contributor. Such primary cells are suppressed, but totals would still reveal them, so secondary cells are suppressed as well, chosen to minimise information loss. Alternatively the table can be controlled-rounded. tauargus does this from a batch file.

Quick start

From a DataFrame

protect() is available from version 0.3.0. Install with pip install --upgrade "pytauargus[dataframe]>=0.3.0" to include pandas support. For a source checkout, follow the source-build instructions, then run uv sync --extra dataframe here.

import pandas as pd
from pytauargus import protect

micro = pd.DataFrame({
    "Region": ["North"] * 6 + ["South"] * 6,
    "Sector": ["Retail"] * 3 + ["Services"] * 3
              + ["Retail"] * 3 + ["Services"] * 3,
    "Turnover": [100., 5., 5., 10., 10., 10., 20., 20., 20., 30., 30., 30.],
})
result = protect(
    micro, ["Region", "Sector"], response="Turnover",
    safety_rules="NK(2,75)", suppress="OPT(1)", workdir="tauargus_run",
)
table = result.tables[0]
publication = table.dataframe()[["Region", "Sector"]].copy()
publication["Turnover"] = table.safe()
publication.to_csv("protected.csv", index=False)
print(publication)

Each row is one respondent. NK(2,75) flags cells whose two largest contributors exceed 75% of the response. The engine computes the crossing and totals, identifies primary unsafe cells, and adds secondary suppression. protect() coordinates microdata, metadata, batch generation and result parsing.

Pandas is optional for the core API: column dicts, lists of row dicts and polars DataFrames are accepted too. dataframe() returns a pandas DataFrame when available, otherwise polars, otherwise a list of row dicts. Column labels become strings and must remain unique after conversion. Column dicts require equal lengths; row dicts use the ordered union of all keys, with missing fields represented by None.

Parquet files and cloud URLs

Install the optional dependency with pip install "pytauargus[parquet]" (pyarrow). Then protect() also accepts a path to a .parquet file, or an s3://, gs:// or https:// URL to one, instead of a DataFrame:

result = protect("s3://bucket/microdata.parquet",
                 ["Region", "Sector"], response="Turnover",
                 safety_rules="NK(2,75)", suppress="OPT(1)")
result.tables[0].to_parquet("s3://bucket/protected.parquet")

to_parquet writes the published table: the explanatory columns plus the response, with suppressed cells (U and M status) as null. Cloud credentials come from the environment, as pyarrow requires them. The same inputs and outputs work from the command line (protect verb below).

A runnable example lives in data/examples/parquet/: micro.parquet holds eight records crossing Sector and Geo, and

tauargus protect data/examples/parquet/micro.parquet \
    --tables 'Sector,Geo' --response Value \
    --safety 'NK(1,80)' --suppress 'OPT(1)' --out protected.parquet

protects it. The output protected.parquet keeps every published value and writes the unsafe (Alpha, East) cell, plus the cells OPT suppresses to hide it, as null.

Existing batch files

Put the data (.asc), its metadata (.rda) and a batch file in one folder. Paths in a batch file are relative to the working directory.

<OPENMICRODATA> "tau_testW.asc"
<OPENMETADATA>  "tau_testW.rda"
<SPECIFYTABLE>  "Size""Region"|"Var2"||
<SAFETYRULE>    NK(2,75)|NK(0,0)
<READMICRODATA>
<SUPPRESS>      MOD(1)
<WRITETABLE>    (1,3,AS-,"safe-table.txt")

tauargus run demo.arb

This reads the microdata, builds the Size x Region table of Var2, flags cells failing the dominance rule NK(2,75) (two largest contributors may not make up more than 75 %), applies secondary suppression with the modular method, and writes the protected table as code/value pairs, with suppressed values masked. The sample inputs are in the repository's data/ folder.

Batch file commands

The grammar and parameters follow the legacy Tau-Argus 4.1 manual.

Command line

tauargus run      batch.arb   # execute the whole batch
tauargus explore  batch.arb   # load data + metadata, list variables
tauargus compute  batch.arb   # table computation only
tauargus suppress batch.arb   # compute, then apply suppression
tauargus round    batch.arb   # compute, then round
tauargus audit    batch.arb   # feasibility intervals of suppressed cells
tauargus save     batch.arb   # compute, then write tables
tauargus tables   batch.arb   # print a table summary
tauargus protect  micro.parquet --tables 'Region,Sector' --response Turnover
version

protect runs the whole pipeline on microdata without a batch file: it specifies the tables, applies the safety rules and the suppression method, and writes the protected table. --out names the output; a .parquet suffix writes a masked Parquet file (requires the parquet extra), any other name writes the published CSV. --tables is repeated for multiple tables; --safety and --suppress take the same rule bodies as the batch file. The microdata argument is a .parquet path or a cloud URL (s3://, gs://, https://).

tauargus protect micro.parquet --tables 'Region,Sector' --response Turnover \
    --safety 'NK(2,75)' --suppress 'OPT(1)' --out protected.parquet

Exit code is 0 on success and non-zero on an error, with a message on stderr, so it fits into scripts and pipelines.

Audit (Intervalle)

A suppressed cell has a range of values it could take while staying consistent with the published totals, its realized lower/upper bounds, the feasibility interval. Protection requires sufficient uncertainty to meet the configured protection requirements. A narrow interval can reveal the original value or constrain it too closely; interval width alone does not establish protection. The audit checks for insufficient protection.

In legacy Tau-Argus this ran in a separate intervalle.exe (standalone Delphi/Pascal executable); Tau-Argus wrote a .JJ file, launched it externally and read the intervals back. The rewrite ports that logic into the engine (TauAuditJj in the csp module), so it runs in-process over a temporary .JJ file with nothing external to install:

from pytauargus.engine import run_batch

engine = run_batch("demo.arb")
rows = engine.audit(0)   # one dict per suppressed cell:
# {"cell", "min", "max", "value", "status", "unsafe"}

The realized bounds are stored on the table (readable via get_table_cell). tauargus save demo.arb --audit --format intermediate writes the legacy INTERMEDIATE (type-5) audit file with the realized-interval columns.

Python API

DataFrame protection

from pytauargus import protect, ProtectResult, TableResult

# Multiple tables; scalar options are recycled across them.
result = protect(
    micro, [["Region", "Sector"], ["Region"]], response="Turnover",
    safety_rules="NK(2,75)", suppress="OPT(1)", workdir="multi_table_run",
)
assert isinstance(result, ProtectResult)
assert all(isinstance(table, TableResult) for table in result.tables)

Explanatory and response names must be unique within each table. The magnitude result reserves freq, cost, status, lower and upper for diagnostics; rename colliding source columns before calling protect(). Invalid names and suppression sequences whose length is neither 1 nor the table count raise ValueError before any input files are written.

Metadata and table options include weight_var, weighted, holding_var, decimals, hrc, totcode, missing and codelist; see help(protect). The high-level API requires a numeric response column; frequency-only tables using the batch <freq> response use the lower-level API.

ProtectResult contains .tables in input order, .engine after the batch, .files (asc, rda, arb, tab1, …) and .workdir. With run=False, .tables is empty and .engine is None; the planned .tab files are not created by that call. Files persist so callers can inspect them and choose when to remove them.

Use the explanatory columns plus safe() to construct the publication table, as in the quickstart. dataframe() does not mask the response automatically. safe(None) uses missing values instead of x.

Audit is explicit and engine indices are zero-based:

rows = result.engine.audit(0)  # realized min/max and insufficient-protection flag
result.engine.write_intermediate_table(0, "audit.tab", with_audit=True)

The lower / upper columns in the default result are protection levels; realized bounds are returned by audit(). TableResult is a parsed snapshot and does not refresh when the engine is audited or modified. Raw intermediates and audit reports contain original values and belong with analyst artifacts. The list-of-dicts fallback from dataframe() is a defensive copy, so editing it does not change the result's subsequent safe() or status() values.

Existing batches and individual commands

from pytauargus.engine import run_batch

engine = run_batch("demo.arb")   # parse and execute; returns the Engine

Lower-level pieces: pytauargus.batch.parse_batch(path) returns the parsed command list, and pytauargus.engine.Engine executes commands one at a time.

Generating batch inputs

pytauargus also generates the batch inputs. The generator is a port of rtauargus, so it emits the exact formats the engine reads:

from pytauargus.arb import micro_arb

micro_arb(
    asc_filename="donnees.asc",
    explanatory_vars=[["REGION"], ["SEXE"]],
    response_var="CA",
    safety_rules=["NK(1,85)", "FREQ(3,10)"],
    suppress="OPT(.)",
    output_names=["tab1.csv", "tab2.csv"],
    output_type="1",  # CSV; the generator default is SBS/type 4
)

pytauargus.micro.micro_asc_rda writes the fixed-width .asc file and its .rda metadata. micro_arb references those files and writes a .arb batch. pytauargus.hrc.write_hrc writes .hrc hierarchy files; the separate pytauargus.rda.write_rda writer handles metadata text. protect() coordinates these steps automatically; protect(..., run=False) previews the complete generated pipeline without running it.

Example notebooks

notebooks/ contains three executed, output-saved notebooks that double as API documentation (every code cell runs against the verified public API):

Run them interactively, or headless (the same command CI could use). The notebooks extra includes pandas for the DataFrame examples:

# interactive
uv sync --extra notebooks
uv run --with jupyterlab jupyter lab notebooks/

# headless: execute every notebook and re-save its outputs
uv run --with nbclient --with nbformat --with ipykernel python notebooks/_run.py

uv run --with nbclient --with nbformat --with ipykernel pytest -k notebooks executes them as tests too (the test skips when nbclient is absent, so the default uv run pytest gate stays dependency-free).

Protection regression tests

uv run pytest tests/test_protection_e2e.py runs OPT and MOD on two cases. The ex1 tabular case checks the legacy 20% manual protection margin, confirms that the original cell is recoverable before secondary suppression, and checks its realised lower and upper protection after suppression. The microdata case adapts the basic dominance example from GaussSuppression's magnitude-table vignette, by Statistics Norway. Contributions are scaled by ten to give integer input; each row is treated as an independent contribution, without company IDs or hierarchies. It checks the four cells selected by the 80% dominance rule.

Both cases run the feasibility audit and read back a CSV containing only dimensions and masked publication values. Primary and secondary suppressed values must be masked, and unmasked values must be retained. The tests do not require a particular secondary suppression pattern and do not compare results against the Gauss algorithm. They cover these two examples, not singleton knowledge, linked-table disclosure or general statistical safety.

Acknowledgements

This project builds on Tau-Argus, its statistical methods and native libraries, and the R and Python tools around it, developed by the people named below.

Original Tau-Argus and native libraries

The original Tau-Argus authors and contributors include Statistics Netherlands (CBS), Peter-Paul de Wolf, Anco Hundepool, Sarah Giessing (GHMITER and audit), Juan José Salazar González (optimisation methods), and Jordi Castro (network solutions and CTA).

The engine uses HiGHS as its open-source LP/MIP solver.

R and Python interfaces

rtauargus is developed at INSEE / InseeFrLab by Pierre-Yves Berrard, Julien Jamme, Nathanaël Rastout, Jeanne Pointet, Félix Beroud, André-Raymond Socard, Wistan Pomel, Clara Baudry, and contributors. Its metadata, batch and hierarchy generation logic was ported to pytauargus; its micro_rtauargus() workflow also informed the high-level protect() pipeline.

PiArgus (piargus), by Laurent Verweijen (lverweijen) and contributors, inspired the DataFrame-to-table workflow and TableResult with its safe(), status(), unsafe() and dataframe() accessors.

GaussSuppression is developed at Statistics Norway by Øyvind Langsrud, Daniel Lupp, Hege Bøvelstad and contributors. The protection regression tests adapt the dominance example from its magnitude-table vignette.

License

EUPL-1.2. Tau-Argus is (c) Statistics Netherlands.