xrfm 0.3.0

xRFM: Scalable and interpretable kernel methods for tabular data

xRFM - Recursive Feature Machines optimized for tabular data

xRFM is a scalable implementation of Recursive Feature Machines (RFMs) optimized for tabular data. This library provides both the core RFM algorithm and a tree-based extension (xRFM) that enables efficient processing of large datasets through recursive data splitting.

Core Components

xRFM/
├── xrfm/
│   ├── xrfm.py              # Main xRFM class (tree-based)
│   ├── tree_utils.py        # Tree manipulation utilities
│   └── rfm_src/
│       ├── recursive_feature_machine.py  # Base RFM class
│       ├── kernels.py       # Kernel implementations
│       ├── eigenpro.py      # EigenPro optimization
│       ├── utils.py         # Utility functions
│       ├── svd.py           # SVD operations
│       └── gpu_utils.py     # GPU memory management
├── examples/                # Usage examples
└── setup.py                # Package configuration

Installation

pip install xrfm

Development Installation

git clone https://github.com/dmbeaglehole/xRFM.git
cd xRFM
pip install -e .

Quick Start

Basic Usage

import torch
from xrfm import xRFM
from sklearn.model_selection import train_test_split

# Create synthetic data
def target_function(X):
    return torch.cat([
        (X[:, 0] > 0)[:, None], 
        (X[:, 1] < 0.5)[:, None]
    ], dim=1).float()

# Setup device and model
device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')
model = xRFM(device=device, tuning_metric='mse')

# Generate data
n_samples = 2000
n_features = 100
X = torch.randn(n_samples, n_features, device=device)
y = target_function(X)
X_trainval, X_test, y_trainval, y_test = train_test_split(X, y, test_size=0.2, random_state=0)
X_train, X_val, y_train, y_val = train_test_split(X_trainval, y_trainval, test_size=0.2, random_state=0)

model.fit(X_train, y_train, X_val, y_val)
y_pred_test = model.predict(X_test)

Custom Configuration

# Custom RFM parameters
rfm_params = {
    'model': {
        'kernel': 'l2',           # Kernel type
        'bandwidth': 5.0,         # Kernel bandwidth
        'exponent': 1.0,          # Kernel exponent
        'diag': False,            # Diagonal Mahalanobis matrix
        'bandwidth_mode': 'constant'
    },
    'fit': {
        'reg': 1e-3,              # Regularization parameter
        'iters': 5,               # Number of iterations
        'M_batch_size': 1000,     # Batch size for AGOP
        'verbose': True,          # Verbose output
        'early_stop_rfm': True    # Early stopping
    }
}

# Initialize model with custom parameters
model = xRFM(
    rfm_params=rfm_params,
    device=device,
    min_subset_size=10000,        # Minimum subset size for splitting
    tuning_metric='accuracy',     # Tuning metric
    split_method='top_vector_agop_on_subset'  # Splitting strategy
)

File Structure

Core Files

File	Description
xrfm/xrfm.py	Main xRFM class implementing tree-based recursive splitting
xrfm/rfm_src/recursive_feature_machine.py	Base RFM class with core algorithm
xrfm/rfm_src/kernels.py	Kernel implementations (Laplace, Product Laplace, etc.)
xrfm/rfm_src/eigenpro.py	EigenPro optimization for large-scale training
xrfm/rfm_src/utils.py	Utility functions for matrix operations and metrics
xrfm/rfm_src/svd.py	SVD utilities for kernel computations
xrfm/rfm_src/gpu_utils.py	GPU memory management utilities
xrfm/tree_utils.py	Tree manipulation and parameter extraction utilities

Example Files

File	Description
examples/test.py	Simple regression example with synthetic data
examples/covertype.py	Forest cover type classification example

API Reference

Main Classes

xRFM

Tree-based Recursive Feature Machine for scalable learning.

Constructor Parameters:

• rfm_params (dict): Parameters for base RFM models
• min_subset_size (int, default=60000): Minimum subset size for splitting
• max_depth (int, default=None): Maximum tree depth
• device (str, default=None): Computing device ('cpu' or 'cuda')
• tuning_metric (str, default='mse'): Metric for model tuning
• split_method (str): Data splitting strategy

Key Methods:

• fit(X, y, X_val, y_val): Train the model
• predict(X): Make predictions
• predict_proba(X): Predict class probabilities
• score(X, y): Evaluate model performance

RFM

Base Recursive Feature Machine implementation.

Constructor Parameters:

• kernel (str or Kernel): Kernel type or kernel object
• iters (int, default=5): Number of training iterations
• bandwidth (float, default=10.0): Kernel bandwidth
• device (str, default=None): Computing device
• tuning_metric (str, default='mse'): Evaluation metric

Available Kernels

Kernel	String ID	Description
LaplaceKernel	'laplace', 'l2'	Standard Laplace kernel
LightLaplaceKernel	'l2_high_dim', 'l2_light'	Memory-efficient Laplace kernel
ProductLaplaceKernel	'product_laplace', 'l1'	Product of Laplace kernels
SumPowerLaplaceKernel	'sum_power_laplace', 'l1_power'	Sum of powered Laplace kernels

Splitting Methods

Method	Description
'top_vector_agop_on_subset'	Use top eigenvector of AGOP matrix
'random_agop_on_subset'	Use random eigenvector of AGOP matrix
'top_pc_agop_on_subset'	Use top principal component of AGOP
'random_pca'	Use vector sampled from Gaussian distribution with covariance $X^\top X$
'linear'	Use linear regression coefficients
'fixed_vector'	Use fixed projection vector

Tuning Metrics

Metric	Description	Task Type
'mse'	Mean Squared Error	Regression
'accuracy'	Classification Accuracy	Classification
'auc'	Area Under ROC Curve	Classification
'f1'	F1 Score	Classification