ExVrp

Elixir bindings for PyVRP, a state-of-the-art Vehicle Routing Problem (VRP) solver.

Uses the same C++ core as PyVRP via NIFs for high-performance solving of CVRP, VRPTW, multi-depot, heterogeneous fleet, prize-collecting, and multi-trip problems.

Installation

Add ex_vrp to your dependencies in mix.exs:

def deps do
  [
    {:ex_vrp, "~> 0.4.0"}
  ]
end

Precompiled NIF binaries are available for Linux (x86_64) and macOS (ARM). On other platforms, a C++20 compiler is required.

Quick Start

model =
  ExVrp.Model.new()
  |> ExVrp.Model.add_depot(x: 0, y: 0)
  |> ExVrp.Model.add_vehicle_type(num_available: 2, capacity: [100])
  |> ExVrp.Model.add_client(x: 10, y: 10, delivery: [20])
  |> ExVrp.Model.add_client(x: 20, y: 0, delivery: [30])
  |> ExVrp.Model.add_client(x: 0, y: 20, delivery: [25])

{:ok, result} = ExVrp.solve(model, max_iterations: 1000, seed: 42)

result.best.routes     #=> [[1, 2], [3]]
result.best.distance   #=> 8944
result.best.is_feasible #=> true

Features

• Parallel multi-start solving (automatic core utilization)
• Time windows, service durations, and shift constraints
• Multi-dimensional capacity (weight, volume, etc.)
• Prize-collecting with optional clients
• Multi-trip routes with depot reloads
• Same-vehicle grouping constraints
• Custom distance/duration matrices
• Configurable stopping criteria
• Progress callbacks

See the full documentation for detailed API reference and examples.

Development

Prerequisites

• Elixir 1.15+
• C++20 compiler (gcc 11+ or clang 14+)
• Make

Setup

mix deps.get
mix compile
mix test

License

MIT License - see LICENSE file.

Acknowledgments

• PyVRP - The underlying solver
• Fine - Ergonomic C++ NIF bindings