majesticlabs-dev/majestic-marketplace

anomaly-detector

Detect anomalies in data using statistical and ML methods.

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Mode d’emploi

  1. Copiez la commande et examinez le paquet avant de l’installer dans votre environnement agent.
  2. Consultez le document original pour les outils, identifiants et environnements requis.
  3. Décrivez les entrées et le livrable souhaité ; comparez la sortie aux sources.
npx skills add https://github.com/majesticlabs-dev/majestic-marketplace --skill anomaly-detector

Avant de commencer

  • L’installation n’inclut ni abonnement au modèle, ni quota API, ni accès aux fichiers.
  • Étoiles et installations reflètent l’activité, pas un test indépendant de qualité ou de sécurité.
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Anomaly Detector

Audience: Data engineers and analysts detecting outliers in datasets.

Goal: Provide production-ready anomaly detection functions for various data types.

Scripts

Execute detection functions from scripts/anomaly_detection.py:

python
from scripts.anomaly_detection import (
    detect_anomalies_zscore,
    detect_anomalies_iqr,
    detect_anomalies_modified_zscore,
    detect_anomalies_isolation_forest,
    detect_anomalies_lof,
    detect_anomalies_rolling,
    detect_anomalies_stl,
    detect_anomalies_ensemble
)

Method Selection

MethodBest ForLimitations
Z-ScoreNormal distributionsSensitive to outliers
IQRSkewed distributionsLess sensitive overall
Modified Z-ScoreRobust detectionSlower computation
Isolation ForestHigh-dimensional dataRequires tuning
LOFLocal density anomaliesComputationally expensive
RollingTime-series with trendsWindow size sensitive
STLSeasonal time-seriesRequires known period

Usage Examples

Single Column Detection

python
import pandas as pd
from scripts.anomaly_detection import detect_anomalies_zscore, detect_anomalies_iqr

df = pd.read_csv('data.csv')

# Z-score method (good for normal distributions)
anomalies_z = detect_anomalies_zscore(df['value'], threshold=3.0)

# IQR method (robust to skewed data)
anomalies_iqr = detect_anomalies_iqr(df['value'], multiplier=1.5)

print(f"Z-score found {anomalies_z.sum()} anomalies")
print(f"IQR found {anomalies_iqr.sum()} anomalies")

Multi-Column with Isolation Forest

python
from scripts.anomaly_detection import detect_anomalies_isolation_forest

numeric_cols = ['revenue', 'quantity', 'price']
anomalies = detect_anomalies_isolation_forest(df, numeric_cols, contamination=0.01)

df_anomalies = df[anomalies]

Ensemble Approach (Recommended)

python
from scripts.anomaly_detection import detect_anomalies_ensemble

results = detect_anomalies_ensemble(
    df,
    columns=['revenue', 'quantity'],
    methods=['zscore', 'iqr', 'isolation_forest'],
    min_agreement=2  # Flag if 2+ methods agree
)

confirmed_anomalies = df[results['is_anomaly']]

Time-Series Anomalies

python
from scripts.anomaly_detection import detect_anomalies_rolling, detect_anomalies_stl

# Rolling window (for trending data)
anomalies = detect_anomalies_rolling(df['daily_sales'], window=7, n_std=2.0)

# STL decomposition (for seasonal data)
anomalies = detect_anomalies_stl(df['monthly_revenue'], period=12, threshold=3.0)

Dependencies

pandas
numpy
scikit-learn  # For Isolation Forest, LOF
statsmodels   # For STL decomposition

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