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PrefGraph

Rationality scores for every user. Rust engine, Python interface.

PyPI Documentation License: MIT

pip install prefgraph

Quick Example

Score how consistently each user's choices align with rational utility maximization:

from prefgraph.datasets import load_demo
from prefgraph.engine import Engine

# 100 synthetic shoppers (prices x quantities), no download needed
users = load_demo()

# Engine scores every user in parallel via Rust/Rayon
engine = Engine(metrics=["garp", "ccei", "mpi", "harp", "hm"])
results = engine.analyze_arrays(users)

for r in results[:3]:
    print(r)
EngineResult: [+] GARP-consistent  ccei=1.0000  hm=15/15  (42us)
EngineResult: [-] 3 violations  ccei=0.8472  mpi=0.0231  hm=12/15  (38us)
EngineResult: [+] GARP-consistent  ccei=1.0000  hm=15/15  (35us)

Every score is a feature you can plug into downstream models. In our benchmarks across 11 e-commerce datasets, revealed preference features rank among the top ten by model importance but add near-zero marginal lift over well-constructed baselines. See the case studies for details.

Your Data

Have a DataFrame? One line:

import prefgraph as rp

# Transaction logs (one row per user x time x item)
results = rp.analyze(df, user_col="user_id", item_col="product",
                     cost_col="price", action_col="quantity", time_col="week")

# Wide format (one row per observation, goods as columns)
results = rp.analyze(df, user_col="user_id",
                     cost_cols=["price_A", "price_B"],
                     action_cols=["qty_A", "qty_B"])

# Menu/click data (which items were shown, which was picked)
results = rp.analyze(df, user_col="user_id",
                     menu_col="shown_items", choice_col="clicked")

Returns a DataFrame with one row per user. Customize with metrics=["garp", "ccei", "mpi", "hm"].

Scores

Score Field What it measures Range
Consistency is_garp Are choices rationalizable? (GARP) bool
Efficiency ccei How close to perfectly rational? (Afriat) 0-1
Exploitability mpi Value left on the table per choice (Karp cycle) 0-1
Homotheticity is_harp Do preferences scale with budget? bool
Rationalizable fraction hm_consistent/hm_total Fraction of rationalizable choices (Houtman-Maks) 0-1
Utility recovery utility_success Can latent utility be reconstructed? (Afriat LP) bool
Per-obs efficiency vei_mean Average efficiency across observations (Varian) 0-1

Which API?

Engine Function API
Use case Score thousands of users Deep-dive one user
Speed 2,000-49,000 users/sec (Rust) Single-user
Returns EngineResult (flat scores) GARPResult, AEIResult, etc. (matrices, cycles, graphs)
Metrics 7 (garp, ccei, mpi, harp, hm, utility, vei) + network 30+ algorithms
Input list[(prices, quantities)] BehaviorLog

Engine for batch scoring. Function API when you need violation details, observation/item graphs, or advanced tests:

from prefgraph import BehaviorLog, validate_consistency, compute_integrity_score

# 3 shopping trips, 2 goods
session = BehaviorLog(cost_vectors=prices, action_vectors=quantities)

# GARP: does a consistent utility function exist?
garp = validate_consistency(session)       # GARPResult with violation cycles, matrices

# CCEI: how much must budgets shrink to remove contradictions?
ccei = compute_integrity_score(session)    # AEIResult with binary search details

Budget and Menu Choices

PrefGraph supports two primary choice domains:

Category Input format Example domain Key tests
Budget (prices T x K, quantities T x K) E-commerce, grocery, food delivery GARP, CCEI, MPI, HM, HARP, VEI
Discrete (menus, choices) or (menus, frequencies) Surveys, A/B tests, recommendations, LLM eval SARP, WARP, HM, RUM LP, IIA

Performance

The Rust engine (rpt-core) handles graph algorithms and LP solving via Rayon thread pool. Python handles I/O and the user-facing API.

Configuration Throughput 10K users 100K users
GARP only ~49,000/s 0.1s 2.0s
GARP + CCEI ~2,400/s 4.2s 39.5s
Comprehensive (GARP, CCEI, MPI, HARP) ~2,000/s 6.8s 67.1s
Menu (SARP + WARP + HM) ~1,900/s 0.3s 5.2s

Memory stays flat via streaming chunks.

Documentation

Full docs at prefgraph.readthedocs.io:

License

MIT

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Measuring Consistency in Choices through Revealed Preference Graphs

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