Mimir-RGNN

Mimir-RGNN is a Python library that implements Relational Graph Neural Networks (R-GNN) for AI planning applications. Built on PyTorch and Mimir, it provides a powerful and flexible interface for learning on structured relational data, particularly PDDL planning domains.

Key Features

• 🧠 Relational Graph Neural Networks: R-GNN implementation for structured reasoning
• 📋 PDDL Integration: Seamless integration with PDDL planning domains and problems via Mimir
• ⚡ PyTorch Backend: Built on PyTorch for GPU acceleration
• 🔧 Flexible Configuration: Declarative configuration system for input/output specifications
• 🎯 Planning-Focused: Designed specifically for AI planning and reinforcement learning applications
• 📊 Multiple Aggregation Functions: Support for various message aggregation strategies
• 🏗️ Typed API: Clean and type-safe interface

Installation

Install Mimir-RGNN from PyPI:

pip install pymimir-rgnn

Requirements

• Python 3.11+
• PyTorch 2.6.0+
• Pymimir 0.14.0b2+

Quick Start

import pymimir as mm
import pymimir_rgnn as rgnn

# Load a PDDL domain
domain = mm.Domain.from_file('path/to/domain.pddl')

# Configure the R-GNN hyperparameters
hparam_config = rgnn.HyperparameterConfig(
    domain=domain,
    embedding_size=64,
    num_layers=30,
)

# Define input and output specifications using encoder/decoder classes
input_spec = (rgnn.StateEncoder(), rgnn.GroundActionsEncoder(), rgnn.GoalEncoder())
output_spec = [('q_values', rgnn.ActionScalarDecoder(hparam_config))]

# Configure the R-GNN modules (aggregation, message, and update functions)
module_config = rgnn.ModuleConfig(
    aggregation_function=rgnn.MeanAggregation(),
    message_function=rgnn.PredicateMLPMessages(hparam_config, input_spec),
    update_function=rgnn.MLPUpdates(hparam_config)
)

# Create and initialize the model
model = rgnn.RelationalGraphNeuralNetwork(hparam_config, module_config, input_spec, output_spec)

# Use the model for inference
# problem = mm.Problem.from_file(domain, 'path/to/problem.pddl')
# state = problem.initial_state
# actions = state.applicable_actions()
# goal = problem.goal
#
# inputs = [(state, actions, goal)]  # Input tuple matching input_spec order
# outputs = model(inputs)
# q_values = outputs.readout('q_values')

Pymimir 0.14.0b2 exposes complete derived-state and PDDL type information. Mimir-RGNN encodes those features directly from the public interface. Numeric PDDL remains intentionally unsupported. See the migration decision log for the interface contract and graph-schema changes.

API Overview

Core Components

HyperparameterConfig

Configuration class for R-GNN model hyperparameters:

• Domain: The PDDL domain for the planning problem
• Model Parameters: Embedding size, number of layers
• Training Settings: Normalization, global readout options

ModuleConfig

Configuration class for R-GNN neural network modules:

• Aggregation Function: How messages are aggregated (mean, sum, max, etc.)
• Message Function: How messages are computed between related nodes
• Update Function: How node embeddings are updated with aggregated messages

Encoder/Decoder Classes

Extensible class-based system for defining inputs and outputs:

• Input Specification: Tuple of encoder instances (StateEncoder, GoalEncoder, etc.)
• Output Specification: List of named decoder instances with custom readout logic

RelationalGraphNeuralNetwork

The main R-GNN model class that:

• Takes hyperparameter config, module config, input specification, and output specification
• Processes relational graph structures from PDDL problems
• Supports extensible encoder/decoder system for custom input/output handling
• Handles batched inference efficiently

Encoder Classes

Inherit from Encoder base class to define custom input processing:

• StateEncoder: Current state of the planning problem
• GoalEncoder: Goal specification
• GroundActionsEncoder: Available ground actions
• TransitionEffectsEncoder: Action effects and transitions

Decoder Classes

Inherit from Decoder base class to define custom output readout:

input_spec = (StateEncoder(), GroundActionsEncoder(), GoalEncoder())
output_spec = [
    ('actor', ActionScalarDecoder(hparam_config)),
    ('critic', ObjectsScalarDecoder(hparam_config)), 
    ('embeddings', ActionEmbeddingDecoder())
]

Aggregation Functions

Available in the ModuleConfig:

• MeanAggregation(): Mean aggregation
• SumAggregation(): Sum aggregation
• HardMaximumAggregation(): Hard maximum
• SmoothMaximumAggregation(): Smooth maximum (LogSumExp)

Examples and Tutorials

For an comprehensive example, visit:

• Example Project Repository

Contributing

We welcome contributions! Please see our Contributing Guidelines for details on:

• Development setup
• Coding standards
• Testing requirements
• Pull request process

License

This project is licensed under the GNU General Public License v3.0 or later. See the LICENSE file for details.

Citation

If you use Mimir-RGNN in your research, please cite:

@inproceedings{stahlberg-bonet-geffner-icaps2022,
  author       = {Simon St{\aa}hlberg and Blai Bonet and Hector Geffner},
  title        = {Learning General Optimal Policies with Graph Neural Networks: Expressive Power, Transparency, and Limits},
  booktitle    = {Proceedings of the Thirty-Second International Conference on Automated Planning and Scheduling, {ICAPS} 2022, Singapore (virtual), June 13-24, 2022},
  pages        = {629--637},
  year         = {2022}
}

Support

• 🐛 Bug Reports: GitHub Issues
• 📧 Contact: simon.stahlberg@gmail.com