Blazematch

Rust-accelerated record linkage and deduplication for Python.

Blazematch pairs a high-level Python API with a Rust core to make entity matching fast without sacrificing usability. Define blocking rules, pick similarity metrics, and fit a model — all in a few lines of pandas-friendly code. The heavy lifting (similarity computation, feature matrix construction, model inference) runs in Rust with Rayon parallelism and GIL release, so Python never becomes the bottleneck.

---

Highlights

• 11 similarity metrics computed in parallel via Rayon
• SQL blocking powered by DuckDB — write rules like "l.city = r.city"
• ANN blocking with TF-IDF + FAISS for fuzzy candidate generation
• 10 models — 6 supervised + 4 unsupervised (no labels needed)
• Deduplication mode with connected-component clustering
• 8 visualizations with Altair (interactive) and matplotlib backends
• Streaming support for datasets larger than RAM
• RAM estimation before you run the pipeline

Installation

pip install blazematch

Build from source (requires Rust and maturin):

git clone https://github.com/yourusername/blazematch.git
cd blazematch
pip install maturin
maturin develop --release

Optional extras

pip install blazematch[ann]       # FAISS-based embedding blocking
pip install blazematch[viz]       # Altair interactive charts
pip install blazematch[xgboost]   # XGBoost model
pip install blazematch[lightgbm]  # LightGBM model

---

Quick Start

Record Linkage

import pandas as pd
from blazematch import Linker, LinkConfig, BlockingRule, FieldComparison, Metric

df_left = pd.DataFrame({
    "name": ["Alice Smith", "Bob Jones", "Carol White"],
    "city": ["New York", "Boston", "New York"],
    "dob":  ["1990-01-15", "1985-06-20", "1992-03-10"],
})

df_right = pd.DataFrame({
    "name": ["A. Smith", "Robert Jones", "Carol Whyte"],
    "city": ["New York", "Boston", "New York"],
    "dob":  ["1990-01-15", "1985-06-20", "1992-03-10"],
})

config = LinkConfig(
    blocking_rules=[BlockingRule("l.city = r.city")],
    comparisons=[
        FieldComparison("name", "name", Metric.JARO_WINKLER),
        FieldComparison("dob",  "dob",  Metric.DATE_DISTANCE, date_format="%Y-%m-%d"),
    ],
)

linker = Linker(df_left, df_right, config)
linker.block().compute_features().estimate()
results = linker.predict(threshold=0.8)
print(results)
#    left_idx  right_idx     score
# 0         0          0  0.923456
# 1         2          2  0.891234

Deduplication

from blazematch import Deduplicator

dedup = Deduplicator(df, config)
dedup.block().compute_features().estimate()
clusters = dedup.cluster(threshold=0.8)
# clusters: DataFrame with [record_idx, cluster_id]

Supervised Training

When you have labelled pairs, swap .estimate() for .fit():

labels = pd.DataFrame({
    "left_idx":  [0, 1, 2],
    "right_idx": [0, 1, 2],
    "label":     [1, 0, 1],
})

linker.block().compute_features().fit(labels, model="random_forest")
results = linker.predict(threshold=0.5)

Available models: "logistic", "random_forest", "gradient_boosting", "svm", "xgboost", "lightgbm".

Preprocessing

Apply text cleaning before comparison:

FieldComparison(
    "name", "name", Metric.JARO_WINKLER,
    preprocess=["lowercase", "strip_whitespace", "remove_punctuation"],
)

Available steps: lowercase, strip_whitespace, remove_punctuation, normalize_unicode.

Embedding Blocking (ANN)

For fuzzy blocking on free-text fields without exact-match rules:

from blazematch import EmbeddingBlockingConfig

config = LinkConfig(
    blocking_rules=[BlockingRule("l.city = r.city")],
    comparisons=[...],
    embedding_blocking=EmbeddingBlockingConfig(
        fields=["name"],
        top_k=10,
        min_sim=0.3,
    ),
)

Requires pip install blazematch[ann].

Save and Load Models

linker.model.save("my_model.pkl")

# Later...
from blazematch import MatchModel
model = MatchModel.load("my_model.pkl")

RAM Estimation

Estimate memory requirements before running the pipeline:

linker.block()
estimate = linker.estimate_ram(model="random_forest")
print(estimate.summary())
# Peak memory: 1.2 GB | System RAM: 16.0 GB | OK to proceed

Visualization

from blazematch import plot_score_distribution, plot_waterfall, plot_roc

plot_score_distribution(results, threshold=0.8)
plot_waterfall(linker, pair_idx=0)
plot_roc(results, labels)

All plot functions accept backend="altair" (default) or backend="matplotlib".

Function	Purpose
plot_score_distribution	Histogram of match scores with optional threshold line
plot_waterfall	Per-feature contribution waterfall for a single pair
plot_comparison_heatmap	Mean feature values for matches vs. non-matches
plot_precision_recall	Precision-recall curve with average precision
plot_roc	ROC curve with AUC
plot_threshold_analysis	Match count across threshold values
plot_match_weights	Per-feature model weights or importances
plot_comparison_viewer	Sampled pair comparisons with field-level detail

---

Similarity Metrics

Metric	Type	Description
JARO_WINKLER	String	Edit-distance variant favoring common prefixes
LEVENSHTEIN	String	Normalized edit distance (0-1)
DAMERAU_LEVENSHTEIN	String	Levenshtein + transpositions
EXACT	String	Binary 0/1 equality
SOUNDEX	String	Phonetic encoding match
JACCARD	String	Token-set intersection over union
COSINE	String	Token-level cosine similarity
TOKEN_SORT_RATIO	String	Order-invariant fuzzy match (sorted tokens + Levenshtein)
NUMERIC	Numeric	Absolute distance
NUMERIC_SIMILARITY	Numeric	Scaled proximity (0-1)
DATE_DISTANCE	Numeric	Absolute days between dates

All string metrics are computed in parallel via Rayon. Numeric metrics operate on f64 slices passed zero-copy from numpy.

---

Models

Supervised (require labelled pairs)

Model	Key	Training	Inference
Logistic Regression	"logistic"	scikit-learn	Rust (ndarray GEMV + sigmoid)
Random Forest	"random_forest"	scikit-learn	Rust (parallel tree traversal)
Gradient Boosting	"gradient_boosting"	scikit-learn	Rust (parallel tree traversal + sigmoid)
SVM (RBF)	"svm"	scikit-learn	Rust (parallel RBF kernel + Platt scaling)
XGBoost	"xgboost"	xgboost	Native C++
LightGBM	"lightgbm"	lightgbm	Native C++

Unsupervised (no labels needed)

Model	Key	Algorithm
Fellegi-Sunter	"fellegi_sunter"	EM-based probabilistic matching with m/u weights
K-Means	"kmeans"	k=2 clustering with optional silhouette auto-tuning
GMM	"gmm"	Gaussian mixture with BIC-based component selection
DBSCAN	"dbscan"	Density-based clustering with auto eps estimation

---

Benchmarks

Pipeline timing at various scales (macOS Apple Silicon, single postcode blocking rule, 3 comparisons):

Records per side	Candidate pairs	Blocking	Features (Rust)	Inference	Full pipeline
1,000	~5K	15 ms	3 ms	<1 ms	40 ms
5,000	~25K	30 ms	15 ms	<1 ms	120 ms
10,000	~50K	50 ms	35 ms	<1 ms	250 ms
50,000	~250K	149 ms	162 ms	3 ms	820 ms

python benchmarks/bench_pipeline.py
python benchmarks/bench_pipeline.py --scales 10000 100000

---

Architecture

Python API                          Rust Core (PyO3 + Rayon)
-----------------------------------+--------------------------------------
Linker / Deduplicator               similarity.rs    11 parallel metrics
  |-- RuleBlocker (DuckDB SQL)      features.rs      single-call feature matrix
  |-- EmbeddingBlocker (FAISS)      inference.rs     logistic regression (GEMV)
  |-- FeatureComputer ------------> tree_inference.rs RF / GBDT (flat numpy arrays)
  |-- MatchModel / RF / GBDT -----> svm_inference.rs  SVM RBF + Platt scaling
  |-- SVMModel ----------------->
  |-- XGBoostModel (native C++)     All batch functions release the GIL
  |-- LightGBMModel (native C++)    and use Rayon for CPU parallelism.
  |-- FellegiSunterModel            Numeric data passed as zero-copy numpy.
  |-- KMeans / GMM / DBSCAN         Tree models use flat numpy arrays with
  +-- Visualize (Altair / mpl)      offsets to avoid per-call serialization.

Design principles:

• Single Rust call for all feature computation — one Python-to-Rust crossing per batch, not per-metric
• Zero-copy numeric data — numpy arrays passed directly to Rust via PyO3, no .tolist() conversion
• Flat tree serialization — sklearn tree structures are flattened into contiguous numpy arrays with offset indices, eliminating repeated list-to-Vec conversion on every predict call
• GIL-free parallelism — every Rust batch function calls py.allow_threads() before Rayon work
• Streaming support — block_iter(), compute_chunked(), and predict_iter() for datasets that don't fit in RAM

---

API Reference

Core

Class	Description
Linker(df_left, df_right, config)	Main record linkage pipeline
Deduplicator(df, config)	Self-join deduplication with clustering
LinkConfig(...)	Pipeline configuration (blocking rules, comparisons, options)
FieldComparison(left, right, metric, ...)	A single field comparison definition
BlockingRule(sql)	SQL join condition for candidate generation
Metric	Enum of available similarity metrics

Blocking

Class	Description
RuleBlocker	DuckDB-powered SQL blocking
EmbeddingBlocker	TF-IDF + FAISS approximate nearest neighbor blocking
EmbeddingBlockingConfig(fields, top_k, min_sim, ...)	ANN blocking configuration

Models

Class	Description
MatchModel	Logistic regression (Rust inference)
RandomForestModel	Random forest (Rust inference)
GradientBoostingModel	Gradient boosting (Rust inference)
SVMModel	SVM with RBF kernel (Rust inference)
XGBoostModel	XGBoost wrapper (native C++ inference)
LightGBMModel	LightGBM wrapper (native C++ inference)
FellegiSunterModel	Unsupervised EM probabilistic matching
KMeansModel	K-Means clustering with optional auto-tuning
GMMModel	Gaussian mixture with BIC auto-tuning
DBSCANModel	DBSCAN with auto eps estimation

Utilities

Function / Class	Description
estimate_ram(...)	Estimate memory requirements for a pipeline configuration
RAMEstimate	Result object with summary(), can_proceed, peak_bytes
apply_preprocess(series, steps)	Apply preprocessing chain to a pandas Series

---

Development

# Setup
git clone https://github.com/yourusername/blazematch.git
cd blazematch
python -m venv .venv && source .venv/bin/activate
pip install -e ".[dev]"
maturin develop --release

# Tests
pytest tests/ -v             # 153 Python tests
cargo test                   # 22 Rust unit tests

# Benchmarks
cargo bench                  # Rust micro-benchmarks (Criterion)
python benchmarks/bench_pipeline.py

# Lint
ruff check python/

Project Structure

blazematch/
  src/                       # Rust source (PyO3 extension module)
    lib.rs                   # Module registration
    similarity.rs            # 11 parallel similarity metrics
    features.rs              # Single-call feature matrix computation
    inference.rs             # Logistic regression batch prediction
    tree_inference.rs        # Random forest / GBDT batch prediction
    svm_inference.rs         # SVM RBF kernel batch prediction
    utils.rs                 # Shared utilities (sigmoid)
  python/blazematch/         # Python source
    linker.py                # Main pipeline orchestrator
    dedup.py                 # Deduplication wrapper
    blocking.py              # Rule-based and ANN blocking
    features.py              # Feature computation bridge to Rust
    model.py                 # Supervised model classes
    fellegi_sunter.py        # Unsupervised EM model
    clustering.py            # K-Means, GMM, DBSCAN models
    config.py                # Configuration dataclasses
    preprocess.py            # Text preprocessing pipeline
    visualize.py             # 8 chart functions
    estimate_ram.py          # Memory estimation
  tests/                     # pytest suite
  benches/                   # Criterion benchmarks

Requirements

• Python >= 3.9
• Rust toolchain (for building from source)
• Core: pandas, numpy, pyarrow, duckdb, scikit-learn, scipy, matplotlib

License

See LICENSE for details.