Greeners: High-Performance Econometrics in Rust

Greeners is a lightning-fast, type-safe econometrics library written in pure Rust. It provides a comprehensive suite of estimators for Cross-Sectional, Time-Series, and Panel Data analysis, leveraging linear algebra backends (LAPACK/BLAS) for maximum performance.

Designed for academic research, heavy simulations, and production-grade economic modeling.

🎊 v1.0.2 STABLE RELEASE: Named Variables & Enhanced Data Loading

Greeners v1.0.2 brings human-readable variable names in regression output and flexible data loading from multiple sources!

🆕 Multiple Data Loading Options (NEW in v1.0.2)

Load data from CSV, JSON, URLs, or use the Builder pattern - just like pandas/polars!

// 1. CSV from URL (reproducible research!)
let df = DataFrame::from_csv_url(
    "https://raw.githubusercontent.com/datasets/gdp/master/data/gdp.csv"
)?;

// 2. JSON from local file (column or record oriented)
let df = DataFrame::from_json("data.json")?;

// 3. JSON from URL (API integration)
let df = DataFrame::from_json_url("https://api.example.com/data.json")?;

// 4. Builder pattern (most convenient!)
let df = DataFrame::builder()
    .add_column("wage", vec![30000.0, 40000.0, 50000.0])
    .add_column("education", vec![12.0, 16.0, 18.0])
    .build()?;

// 5. CSV from local file (classic)
let df = DataFrame::from_csv("data.csv")?;

Why this matters:

✅ Reproducible research - Load datasets directly from GitHub/URLs
✅ API integration - Fetch data from web services
✅ Flexible formats - CSV, JSON (column/record oriented)
✅ Pandas-like - Familiar syntax for data scientists
✅ Type-safe - All data loading is checked at compile time

📖 See examples/dataframe_loading.rs for all loading methods.

Named Variables in Results (NEW in v1.0.2)

No more generic x0, x1, x2 in regression output! All models now display actual variable names from your Formula:

use greeners::{OLS, DataFrame, Formula, CovarianceType};

let formula = Formula::parse("wage ~ education + experience + female")?;
let result = OLS::from_formula(&formula, &df, CovarianceType::HC3)?;

println!("{}", result);

Before (v1.0.1):

OLS Regression Results
====================================
Variable    Coef    Std Err    t    P>|t|
const       5.23    0.45      11.62  0.000
x0          2.15    0.12       17.92  0.000    <- Generic names
x1          0.08    0.02        4.00  0.000
x2         -1.20    0.25       -4.80  0.000

Now (v1.0.2):

OLS Regression Results
====================================
Variable      Coef    Std Err    t    P>|t|
const         5.23    0.45      11.62  0.000
education     2.15    0.12       17.92  0.000    <- Actual variable names!
experience    0.08    0.02        4.00  0.000
female       -1.20    0.25       -4.80  0.000

Applies to ALL models:

✅ OLS, WLS, Cochrane-Orcutt (FGLS)
✅ IV/2SLS (Instrumental Variables)
✅ Logit/Probit (Binary Choice)
✅ Quantile Regression (all quantiles)
✅ Panel Data (Fixed Effects, Random Effects, Between)
✅ GMM (Generalized Method of Moments)
✅ Difference-in-Differences

Comprehensive Test Coverage

v1.0.2 includes 143 unit tests covering all major functionality:

62 new tests added in v1.0.2 across 7 test modules
Full coverage of IV/2SLS, Panel Data, DiD, FGLS, Quantile Regression
Diagnostic tests (VIF, Breusch-Pagan, Jarque-Bera, Durbin-Watson)
GMM specification tests (J-statistic, overidentification)
Model selection and information criteria

Run tests locally:

cargo test              # Run all 143 tests
cargo test --lib        # Library tests only
cargo test quantile     # Specific module tests

Code Quality Improvements

Applied clippy lints for idiomatic Rust (25+ improvements)
Replaced .iter().cloned().collect() with .to_vec() for better performance
Modern range checks using .contains() instead of manual comparisons
Cleaner, more maintainable codebase

🎉 v1.0.1: Specification Tests

Greeners reaches production stability with comprehensive specification tests for diagnosing regression assumptions!

Specification Tests (NEW in v1.0.1)

Diagnose violations of classical regression assumptions and identify appropriate remedies:

use greeners::{OLS, SpecificationTests, Formula, DataFrame, CovarianceType};

// Estimate model
let model = OLS::from_formula(&Formula::parse("wage ~ education + experience")?, &df, CovarianceType::NonRobust)?;
let (y, x) = df.to_design_matrix(&formula)?;
let residuals = model.residuals(&y, &x);
let fitted = model.fitted_values(&x);

// 1. White Test for Heteroskedasticity
let (lm_stat, p_value, df) = SpecificationTests::white_test(&residuals, &x)?;
if p_value < 0.05 {
    println!("Heteroskedasticity detected! Use CovarianceType::HC3");
}

// 2. RESET Test for Functional Form Misspecification
let (f_stat, p_value, _, _) = SpecificationTests::reset_test(&y, &x, &fitted, 3)?;
if p_value < 0.05 {
    println!("Misspecification detected! Add polynomials or interactions");
}

// 3. Breusch-Godfrey Test for Autocorrelation
let (lm_stat, p_value, df) = SpecificationTests::breusch_godfrey_test(&residuals, &x, 1)?;
if p_value < 0.05 {
    println!("Autocorrelation detected! Use CovarianceType::NeweyWest(4)");
}

// 4. Goldfeld-Quandt Test for Heteroskedasticity
let (f_stat, p_value, _, _) = SpecificationTests::goldfeld_quandt_test(&residuals, 0.25)?;

When to Use:

White Test → General heteroskedasticity test (any form)
RESET Test → Detect omitted variables or wrong functional form
Breusch-Godfrey → Detect autocorrelation in time series/panel data
Goldfeld-Quandt → Test heteroskedasticity when you suspect specific ordering

Remedies:

Heteroskedasticity → CovarianceType::HC3 or HC4
Autocorrelation → CovarianceType::NeweyWest(lags)
Misspecification → Add I(x^2), x1*x2 interactions

Stata/R/Python Equivalents:

Stata: estat hettest, estat ovtest, estat bgodfrey
R: lmtest::bptest(), lmtest::resettest(), lmtest::bgtest()
Python: statsmodels.stats.diagnostic.het_white()

📖 See examples/specification_tests.rs for comprehensive demonstration.

✨ NEW: R/Python-Style Formula API

Greeners now supports R/Python-style formula syntax (like statsmodels and lm()), making model specification intuitive and concise:

use greeners::{OLS, DataFrame, Formula, CovarianceType};

// Python equivalent: smf.ols('y ~ x1 + x2', data=df).fit(cov_type='HC1')
let formula = Formula::parse("y ~ x1 + x2")?;
let result = OLS::from_formula(&formula, &df, CovarianceType::HC1)?;

All estimators support formulas: OLS, WLS, DiD, IV/2SLS, Logit/Probit, Quantile Regression, Panel Data (FE/RE/Between), and more!

📖 See FORMULA_API.md for complete documentation and examples.

🚀 NEW in v0.9.0: Panel Diagnostics & Model Selection

Greeners now provides comprehensive tools for panel data model selection and information criteria-based model comparison - essential for rigorous empirical research!

Model Selection & Comparison

Compare multiple models using AIC/BIC with automatic ranking and Akaike weights for model averaging:

use greeners::{OLS, ModelSelection, DataFrame, Formula, CovarianceType};

// Estimate competing models
let model1 = OLS::from_formula(&Formula::parse("y ~ x1 + x2 + x3")?, &df, CovarianceType::NonRobust)?;
let model2 = OLS::from_formula(&Formula::parse("y ~ x1 + x2")?, &df, CovarianceType::NonRobust)?;
let model3 = OLS::from_formula(&Formula::parse("y ~ x1")?, &df, CovarianceType::NonRobust)?;

// Compare models
let models = vec![
    ("Full Model", model1.log_likelihood, 4, n_obs),
    ("Restricted", model2.log_likelihood, 3, n_obs),
    ("Simple", model3.log_likelihood, 2, n_obs),
];
let comparison = ModelSelection::compare_models(models);
ModelSelection::print_comparison(&comparison);

// Calculate Akaike weights for model averaging
let aic_values: Vec<f64> = comparison.iter().map(|(_, aic, _, _, _)| *aic).collect();
let (delta_aic, weights) = ModelSelection::akaike_weights(&aic_values);

Output:

=============================== Model Comparison ===============================
Model                |          AIC |          BIC | Rank(AIC) | Rank(BIC)
--------------------------------------------------------------------------------
Full Model           |       183.83 |       191.48 |        1 |        1
Restricted           |       184.77 |       190.50 |        2 |        2
Simple               |       188.19 |       192.01 |        3 |        3

📊 AKAIKE WEIGHTS:
Δ_AIC < 2: Substantial support
Δ_AIC 4-7: Considerably less support
Δ_AIC > 10: Essentially no support

Panel Diagnostics Tests

Test whether pooled OLS is appropriate or if panel data methods (Fixed/Random Effects) are needed:

Breusch-Pagan LM Test for Random Effects

use greeners::{PanelDiagnostics, OLS, Formula};

// Estimate pooled OLS
let model_pooled = OLS::from_formula(&formula, &df, CovarianceType::NonRobust)?;
let (y, x) = df.to_design_matrix(&formula)?;
let residuals = model_pooled.residuals(&y, &x);

// Test for random effects
let (lm_stat, p_value) = PanelDiagnostics::breusch_pagan_lm(&residuals, &firm_ids)?;

// Interpretation:
// H₀: σ²_u = 0 (no panel effects, pooled OLS adequate)
// H₁: σ²_u > 0 (random effects needed)
// If p < 0.05 → Use Random Effects or Fixed Effects

F-Test for Fixed Effects

// Test if firm fixed effects are significant
let (f_stat, p_value) = PanelDiagnostics::f_test_fixed_effects(
    ssr_pooled,
    ssr_fe,
    n_obs,
    n_firms,
    k_params,
)?;

// Interpretation:
// H₀: All firm effects are zero (pooled OLS adequate)
// H₁: Firm effects exist (use fixed effects)
// If p < 0.05 → Use Fixed Effects model

Summary Statistics

Quick descriptive statistics for initial data exploration:

use greeners::SummaryStats;

let stats = SummaryStats::describe(&data);
// Returns: (mean, std, min, Q25, median, Q75, max, n_obs)

// Pretty-print summary table
let summary_data = vec![
    ("investment", stats_inv),
    ("profit", stats_profit),
    ("cash_flow", stats_cf),
];
SummaryStats::print_summary(&summary_data);

Stata/R/Python Equivalents:

Stata: estat ic (AIC/BIC), xttest0 (BP LM), testparm (F-test)
R: AIC(), BIC(), plm::plmtest(), plm::pFtest()
Python: statsmodels information criteria, linearmodels.panel diagnostics

📖 See examples/panel_model_selection.rs for comprehensive demonstration with panel data workflow.

🌟 NEW in v0.5.0: Marginal Effects for Binary Choice Models

After estimating Logit/Probit models, coefficients alone are hard to interpret (they're on log-odds/z-score scale). Marginal effects translate these to probability changes - essential for policy analysis and substantive interpretation!

Average Marginal Effects (AME) - RECOMMENDED

use greeners::{Logit, Formula, DataFrame};

// Estimate Logit model
let formula = Formula::parse("admitted ~ gpa + sat + legacy")?;
let result = Logit::from_formula(&formula, &df)?;

// Get design matrix
let (_, x) = df.to_design_matrix(&formula)?;

// Calculate Average Marginal Effects (AME)
let ame = result.average_marginal_effects(&x)?;

// Interpretation: AME[gpa] = 0.15 means:
// "A 1-point increase in GPA increases admission probability by 15 percentage points"
// (averaged across all students in the sample)

Why AME?

✅ Accounts for heterogeneity across observations
✅ More robust to non-linearities
✅ Standard in modern econometrics (Stata, R, Python)
✅ Easy to interpret: probability changes, not log-odds

Marginal Effects at Means (MEM)

// Calculate Marginal Effects at Means (MEM)
let mem = result.marginal_effects_at_means(&x)?;

// Interpretation: Effect for "average" student
// ⚠️ Less robust than AME - can evaluate at impossible values (e.g., average of dummies)

Predictions

// Predict admission probabilities for new students
let probs = result.predict_proba(&x_new);

// Example: probs[0] = 0.85 → 85% chance of admission

Logit vs Probit Comparison

// Both models give similar marginal effects
let logit_result = Logit::from_formula(&formula, &df)?;
let probit_result = Probit::from_formula(&formula, &df)?;

let ame_logit = logit_result.average_marginal_effects(&x)?;
let ame_probit = probit_result.average_marginal_effects(&x)?;

// Typically: ame_logit ≈ ame_probit (differences < 1-2 percentage points)

Stata/R/Python Equivalents:

Stata: margins, dydx(*) (AME) or margins, dydx(*) atmeans (MEM)
R: mfx::logitmfx() or margins::margins()
Python: statsmodels.discrete.discrete_model.Logit(...).get_margeff()

📖 See examples/marginal_effects.rs for comprehensive demonstration with college admission data.

Two-Way Clustered Standard Errors

For panel data with clustering along two dimensions (e.g., firms × time):

// Panel data: 4 firms × 6 time periods
let firm_ids = vec![0,0,0,0,0,0, 1,1,1,1,1,1, 2,2,2,2,2,2, 3,3,3,3,3,3];
let time_ids = vec![0,1,2,3,4,5, 0,1,2,3,4,5, 0,1,2,3,4,5, 0,1,2,3,4,5];

// Two-way clustering (Cameron-Gelbach-Miller, 2011)
let result = OLS::from_formula(
    &formula,
    &df,
    CovarianceType::ClusteredTwoWay(firm_ids, time_ids)
)?;

// Formula: V = V_firm + V_time - V_intersection
// Accounts for BOTH within-firm AND within-time correlation

When to use:

✅ Panel data (firms/countries over time)
✅ Correlation within entities AND within time periods
✅ More robust than one-way clustering
✅ Standard in modern panel data econometrics

Stata equivalent: reghdfe y x, vce(cluster firm_id time_id)

📖 See examples/two_way_clustering.rs for complete comparison of non-robust vs one-way vs two-way clustering.

🎊 NEW in v0.4.0: Categorical Variables & Polynomial Terms

Categorical Variable Encoding

Automatic dummy variable creation with R/Python syntax:

// Categorical variable: creates dummies, drops first level
let formula = Formula::parse("sales ~ advertising + C(region)")?;
let result = OLS::from_formula(&formula, &df, CovarianceType::HC3)?;

// If region has values [0, 1, 2, 3] → creates 3 dummies (drops 0 as reference)

How it works:

C(var) detects unique values in the variable
Creates K-1 dummy variables (drops first category as reference)
Essential for categorical data (regions, industries, treatment groups)

Polynomial Terms

Non-linear relationships made easy:

// Quadratic model: captures diminishing returns
let formula = Formula::parse("output ~ input + I(input^2)")?;

// Cubic model: more flexible
let formula = Formula::parse("y ~ x + I(x^2) + I(x^3)")?;

// Alternative syntax (Python-style)
let formula = Formula::parse("y ~ x + I(x**2)")?;

Use cases:

Production functions (diminishing returns)
Wage curves (experience effects)
Growth models (non-linear dynamics)

Combine with interactions:

// Region-specific quadratic effects
let formula = Formula::parse("sales ~ C(region) * I(advertising^2)")?;

🆕 NEW in v0.2.0: Clustered Standard Errors & Advanced Diagnostics

Clustered Standard Errors

Critical for panel data and hierarchical structures where observations are grouped:

// Panel data: firms over time
let cluster_ids = vec![0,0,0, 1,1,1, 2,2,2]; // Firm IDs
let result = OLS::from_formula(&formula, &df, CovarianceType::Clustered(cluster_ids))?;

Use clustered SE when:

Panel data (repeated observations per entity)
Hierarchical data (students in schools, patients in hospitals)
Experimental data with treatment clusters
Geographic clustering (observations in regions/countries)

Advanced Diagnostics

New diagnostic tools for model validation:

use greeners::Diagnostics;

// Multicollinearity detection
let vif = Diagnostics::vif(&x)?;              // Variance Inflation Factor
let cond_num = Diagnostics::condition_number(&x)?;  // Condition Number

// Influential observations
let leverage = Diagnostics::leverage(&x)?;    // Hat values
let cooks_d = Diagnostics::cooks_distance(&residuals, &x, mse)?;  // Cook's Distance

// Assumption testing (already available)
let (jb_stat, jb_p) = Diagnostics::jarque_bera(&residuals)?;  // Normality
let (bp_stat, bp_p) = Diagnostics::breusch_pagan(&residuals, &x)?;  // Heteroskedasticity
let dw_stat = Diagnostics::durbin_watson(&residuals);  // Autocorrelation

🎉 NEW in v0.3.0: Interactions, HC2/HC3, and Predictions

Interaction Terms

Model interaction effects with R/Python syntax:

// Full interaction: x1 * x2 expands to x1 + x2 + x1:x2
let formula = Formula::parse("wage ~ education * female")?;
let result = OLS::from_formula(&formula, &df, CovarianceType::HC3)?;

// Interaction only: just the product term
let formula2 = Formula::parse("wage ~ education + female + education:female")?;

Use cases:

Differential effects by groups (e.g., education returns by gender)
Treatment effect heterogeneity
Testing moderation/mediation hypotheses

Enhanced Robust Standard Errors

// HC2: Leverage-adjusted (more efficient with small samples)
let result_hc2 = OLS::from_formula(&formula, &df, CovarianceType::HC2)?;

// HC3: Jackknife (most robust - RECOMMENDED for small samples)
let result_hc3 = OLS::from_formula(&formula, &df, CovarianceType::HC3)?;

Comparison:

HC1: White (1980), uses n/(n-k) correction
HC2: Adjusts for leverage: σ²/(1-h_i)
HC3: Jackknife: σ²/(1-h_i)² - Most conservative & robust

Post-Estimation Predictions

// Out-of-sample predictions
let x_new = Array2::from_shape_vec((3, 2), vec![1.0, 12.0, 1.0, 16.0, 1.0, 20.0])?;
let predictions = result.predict(&x_new);

// In-sample fitted values
let fitted = result.fitted_values(&x);

// Residuals
let resid = result.residuals(&y, &x);

🚀 Features

Cross-Sectional & General

OLS & GLS: Robust standard errors (White, Newey-West).
IV / 2SLS: Instrumental Variables for endogeneity correction.
Quantile Regression: Robust estimation via Iteratively Reweighted Least Squares (IRLS).
Discrete Choice: Logit and Probit models (Newton-Raphson MLE).
Diagnostics: R-squared, F-Test, T-Test, Confidence Intervals.

Time Series (Macroeconometrics)

Unit Root Tests: Augmented Dickey-Fuller (ADF).
VAR (Vector Autoregression): Multivariate modeling with Information Criteria (AIC/BIC).
VARMA: Hannan-Rissanen algorithm for ARMA structures.
VECM (Cointegration): Johansen Procedure (Eigenvalue decomposition) for I(1) systems.
Impulse Response Functions (IRF): Orthogonalized structural shocks.

Panel Data

Fixed Effects (Within): Absorbs individual heterogeneity.
Random Effects: Swamy-Arora GLS estimator.
Between Estimator: Long-run cross-sectional relationships.
Dynamic Panel: Arellano-Bond (Difference GMM) to solve Nickell Bias.
Panel Threshold: Hansen (1999) non-linear regime switching models.
Testing: Hausman Test for FE vs RE.

Systems of Equations

SUR: Seemingly Unrelated Regressions (Zellner).
3SLS: Three-Stage Least Squares (System IV).

System Requirements (Pre-requisites)

Debian / Ubuntu / Pop!_OS:

sudo apt-get update

sudo apt-get install gfortran libopenblas-dev liblapack-dev pkg-config build-essential

Fedora / RHEL / CentOS:

sudo dnf install gcc-gfortran openblas-devel lapack-devel pkg-config

Arch Linux / Manjaro:

sudo pacman -S gcc-fortran openblas lapack base-devel

macOS:

brew install openblas lapack

📦 Installation

Add this to your Cargo.toml:

[dependencies]
greeners = "1.0.2"
ndarray = "0.15"
# Note: You must have a BLAS/LAPACK provider installed on your system
ndarray-linalg = { version = "0.14", features = ["openblas"] }

🎯 Quick Start

Loading Data (Multiple Options!)

Greeners provides flexible data loading similar to pandas/polars - from local files, URLs, or manual construction:

1. CSV from Local File

use greeners::{DataFrame, Formula, OLS, CovarianceType};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Load data from CSV file with headers (just like pandas!)
    let df = DataFrame::from_csv("data.csv")?;

    // Specify model using formula
    let formula = Formula::parse("y ~ x1 + x2")?;

    // Estimate with robust standard errors
    let result = OLS::from_formula(&formula, &df, CovarianceType::HC1)?;

    println!("{}", result);
    Ok(())
}

2. CSV from URL (NEW!)

// Load data directly from GitHub or any URL
let df = DataFrame::from_csv_url(
    "https://raw.githubusercontent.com/datasets/gdp/master/data/gdp.csv"
)?;

// Perfect for reproducible research and shared datasets!

3. JSON from Local File (NEW!)

// Column-oriented JSON (like pandas.to_json(orient='columns'))
// { "x": [1.0, 2.0, 3.0], "y": [2.0, 4.0, 6.0] }
let df = DataFrame::from_json("data_columns.json")?;

// Or record-oriented JSON (like pandas.to_json(orient='records'))
// [{"x": 1.0, "y": 2.0}, {"x": 2.0, "y": 4.0}]
let df = DataFrame::from_json("data_records.json")?;

4. JSON from URL (NEW!)

// Load JSON directly from APIs or URLs
let df = DataFrame::from_json_url("https://api.example.com/data.json")?;

5. Builder Pattern (NEW!)

// Most convenient for manual data construction
let df = DataFrame::builder()
    .add_column("wage", vec![30000.0, 40000.0, 50000.0])
    .add_column("education", vec![12.0, 16.0, 18.0])
    .add_column("experience", vec![5.0, 7.0, 10.0])
    .build()?;

let formula = Formula::parse("wage ~ education + experience")?;
let result = OLS::from_formula(&formula, &df, CovarianceType::HC3)?;

Supported formats:

✅ CSV (local files)
✅ CSV (URLs) - requires internet connection
✅ JSON (local files) - both column and record oriented
✅ JSON (URLs) - perfect for API integration
✅ Builder pattern - convenient manual construction
✅ HashMap - traditional programmatic construction

📖 See examples/dataframe_loading.rs for comprehensive demonstration of all loading methods.

Using Formula API (R/Python Style)

use greeners::{OLS, DataFrame, Formula, CovarianceType};
use ndarray::Array1;
use std::collections::HashMap;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Create data manually (like a pandas DataFrame)
    let mut data = HashMap::new();
    data.insert("y".to_string(), Array1::from(vec![1.0, 2.0, 3.0, 4.0, 5.0]));
    data.insert("x1".to_string(), Array1::from(vec![1.0, 2.0, 3.0, 4.0, 5.0]));
    data.insert("x2".to_string(), Array1::from(vec![2.0, 2.5, 3.0, 3.5, 4.0]));

    let df = DataFrame::new(data)?;

    // Specify model using formula (just like Python/R!)
    let formula = Formula::parse("y ~ x1 + x2")?;

    // Estimate with robust standard errors
    let result = OLS::from_formula(&formula, &df, CovarianceType::HC1)?;

    println!("{}", result);
    Ok(())
}

Traditional Matrix API

use greeners::{OLS, CovarianceType};
use ndarray::{Array1, Array2};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let y = Array1::from(vec![1.0, 2.0, 3.0, 4.0, 5.0]);
    let x = Array2::from_shape_vec((5, 2), vec![
        1.0, 2.0,
        2.0, 2.5,
        3.0, 3.0,
        4.0, 3.5,
        5.0, 4.0,
    ])?;

    let result = OLS::fit(&y, &x, CovarianceType::HC1)?;
    println!("{}", result);
    Ok(())
}

📚 Formula API Examples

Difference-in-Differences

use greeners::{DiffInDiff, DataFrame, Formula, CovarianceType};

// Python: smf.ols('outcome ~ treated + post + treated:post', data=df).fit(cov_type='HC1')
let formula = Formula::parse("outcome ~ treated + post")?;
let result = DiffInDiff::from_formula(&formula, &df, "treated", "post", CovarianceType::HC1)?;

Instrumental Variables (2SLS)

use greeners::{IV, Formula, CovarianceType};

// Endogenous equation: y ~ x1 + x_endog
// Instruments: z1, z2
let endog_formula = Formula::parse("y ~ x1 + x_endog")?;
let instrument_formula = Formula::parse("~ z1 + z2")?;
let result = IV::from_formula(&endog_formula, &instrument_formula, &df, CovarianceType::HC1)?;

Logit/Probit

use greeners::{Logit, Probit, Formula};

// Binary choice models
let formula = Formula::parse("binary_outcome ~ x1 + x2 + x3")?;
let logit_result = Logit::from_formula(&formula, &df)?;
let probit_result = Probit::from_formula(&formula, &df)?;

Panel Data (Fixed Effects)

use greeners::{FixedEffects, Formula};

let formula = Formula::parse("y ~ x1 + x2")?;
let result = FixedEffects::from_formula(&formula, &df, &entity_ids)?;

Quantile Regression

use greeners::{QuantileReg, Formula};

// Median regression
let formula = Formula::parse("y ~ x1 + x2")?;
let result = QuantileReg::from_formula(&formula, &df, 0.5, 200)?;

🔧 Formula Syntax

Basic: y ~ x1 + x2 + x3 (with intercept)
No intercept: y ~ x1 + x2 - 1 or y ~ 0 + x1 + x2
Intercept only: y ~ 1

All formulas follow R/Python syntax for familiarity and ease of use.

📖 Documentation

FORMULA_API.md - Complete formula API guide with Python/R equivalents
examples/ - Working examples for all estimators
- dataframe_loading.rs - Load data from CSV, JSON, URLs, or Builder pattern (NEW!)
- csv_formula_example.rs - Load CSV files and run regressions
- formula_example.rs - General formula API demonstration
- did_formula_example.rs - Difference-in-Differences with formulas
- quickstart_formula.rs - Quick start example
- marginal_effects.rs - Logit/Probit marginal effects (AME/MEM)
- specification_tests.rs - White, RESET, Breusch-Godfrey, Goldfeld-Quandt tests
- panel_model_selection.rs - Panel diagnostics and model comparison

Run examples:

cargo run --example dataframe_loading    # NEW: Multiple data loading methods
cargo run --example csv_formula_example
cargo run --example formula_example
cargo run --example marginal_effects
cargo run --example specification_tests

🎯 Why Greeners?

Familiar Syntax: R/Python-style formulas make transition seamless
Type Safety: Rust's type system catches errors at compile time
Performance: Native speed with BLAS/LAPACK backends
Comprehensive: Full suite of econometric estimators
Production Ready: Memory safe, no garbage collection pauses

greeners 1.0.2

Greeners: High-Performance Econometrics in Rust

🎊 v1.0.2 STABLE RELEASE: Named Variables & Enhanced Data Loading

🆕 Multiple Data Loading Options (NEW in v1.0.2)

Named Variables in Results (NEW in v1.0.2)

Comprehensive Test Coverage

Code Quality Improvements

🎉 v1.0.1: Specification Tests

Specification Tests (NEW in v1.0.1)

✨ NEW: R/Python-Style Formula API

🚀 NEW in v0.9.0: Panel Diagnostics & Model Selection

Model Selection & Comparison

Panel Diagnostics Tests

Breusch-Pagan LM Test for Random Effects

F-Test for Fixed Effects

Summary Statistics

🌟 NEW in v0.5.0: Marginal Effects for Binary Choice Models

Average Marginal Effects (AME) - RECOMMENDED

Marginal Effects at Means (MEM)

Predictions

Logit vs Probit Comparison

Two-Way Clustered Standard Errors

🎊 NEW in v0.4.0: Categorical Variables & Polynomial Terms

Categorical Variable Encoding

Polynomial Terms

🆕 NEW in v0.2.0: Clustered Standard Errors & Advanced Diagnostics

Clustered Standard Errors

Advanced Diagnostics

🎉 NEW in v0.3.0: Interactions, HC2/HC3, and Predictions

Interaction Terms

Enhanced Robust Standard Errors

Post-Estimation Predictions

🚀 Features

Cross-Sectional & General

Time Series (Macroeconometrics)

Panel Data

Systems of Equations

System Requirements (Pre-requisites)

Debian / Ubuntu / Pop!_OS:

Fedora / RHEL / CentOS:

Arch Linux / Manjaro:

macOS:

📦 Installation

🎯 Quick Start

Loading Data (Multiple Options!)

1. CSV from Local File

2. CSV from URL (NEW!)

3. JSON from Local File (NEW!)

4. JSON from URL (NEW!)

5. Builder Pattern (NEW!)

Using Formula API (R/Python Style)

Traditional Matrix API

📚 Formula API Examples

Difference-in-Differences

Instrumental Variables (2SLS)

Logit/Probit

Panel Data (Fixed Effects)

Quantile Regression

🔧 Formula Syntax

📖 Documentation

🎯 Why Greeners?