COIN-OR Library Stack

The COIN-OR project is organized into dependency layers, where each layer builds on the ones below it. Lower layers provide foundational utilities; higher layers implement complete solvers and applications.

Layer 0: Foundation

Core utilities and sparse linear algebra that all other libraries depend on.

CoinUtils

Foundation utilities: sparse matrices, I/O (MPS/LP), presolve, warm starting

122 classes documented 65 headers

Sparse Matrix LU Factorization Presolve File I/O Warm Start

SuiteSparse

Sparse direct solvers (CHOLMOD, UMFPACK, AMD) for linear algebra

9 classes documented

Cholesky LU Ordering

Layer 1: LP & Cuts

Linear programming solvers, solver interfaces, and cut generation basics.

Clp

COIN-OR LP solver: dual/primal simplex, interior point methods

13 classes documented 90 headers

Simplex Interior Point Presolve Factorization

Osi

Open Solver Interface: common API for LP/MIP solvers

2 classes documented 35 headers

Solver API Branching Cuts

CppAD

C++ algorithmic differentiation for automatic derivatives

2 classes documented 4 headers

Autodiff Gradients Hessians

qpOASES

Online active set QP solver for model predictive control

3 classes documented

QP Active Set MPC

Layer 2: MIP & NLP

Mixed-integer programming and nonlinear optimization solvers.

Cbc

COIN-OR branch-and-cut MIP solver with parallelization

4 classes documented 90 headers

Branch & Cut Heuristics Parallel SOS

Cgl

Cut Generator Library: Gomory, MIR, lift-and-project cuts

6 classes documented 40 headers

Gomory MIR Clique Probing

Ipopt

Interior Point OPTimizer for large-scale nonlinear programming

1 class documented 95 headers

Interior Point NLP Large-scale Filter

ADOL-C

Automatic differentiation via operator overloading

1 class documented

Autodiff Tape-based

Layer 3: MINLP

Mixed-integer nonlinear programming and advanced decomposition methods.

Bonmin

Basic Open-source Nonlinear Mixed INteger programming for convex MINLP

35 files annotated 45 headers

MINLP B&B OA Feasibility Pump

Couenne

Convex Over and Under ENvelopes for global MINLP with spatial B&B

32 files annotated 70 headers

Global Spatial B&B Convexification FBBT

SYMPHONY

Single- or Multi-Process Optimization over Networks (parallel B&C)

4 headers

Parallel Distributed

CHiPPS-ALPS

Abstract Library for Parallel Search tree algorithms

35 headers

Parallel Search Tree Framework

CHiPPS-BLIS

Branch-and-cut with Lp-Based Intelligent Search

27 headers

Branch & Cut Pseudocost

DisCO

Distributed Combinatorial Optimization for parallel MIP

27 headers

Conic SOCP Parallel

Bcp

Branch-Cut-Price parallel framework for column generation

125 files annotated 75 headers

Column Gen Parallel Pricing Decomposition

Dip

Decomposition for Integer Programming (Dantzig-Wolfe, Lagrangean)

1 class documented

Decomposition D-W

Smi

Stochastic Modelling Interface for stochastic programming

Headers only

Stochastic Two-stage

oBB

Optimality-Based Branch-and-Bound for nonconvex MINLP

Headers only

Nonconvex Global

Layer 4: Applications

Modeling tools, solver interfaces, and application-specific systems.

SHOT

Supporting Hyperplane Optimization Toolkit for convex MINLP

15 classes documented 85 headers

ECP ESH Convex MINLP

HiGHS

High-performance LP/MIP solver (simplex, IPM, B&B)

5 classes documented

LP MIP High-perf

GAMSlinks

Interfaces to GAMS optimization modeling system

25 headers

GAMS Modeling Integration

Gravity

High-performance optimization modeling in C++

1 class documented 2 headers

Modeling QCQP SDP

Sonnet

.NET optimization modeling wrapper

24 headers

.NET C# Wrapper

Cmpl

COLIOP Mathematical Programming Language modeling system

Headers only

Modeling Language

OS

Optimization Services: Web services for optimization

Headers only

Web Services OSiL

cuopt

CUDA-accelerated optimization

Headers only

GPU CUDA

Documentation Status

Layer	Libraries	Documentation
Layer 0	2	CoinUtils (122 classes), SuiteSparse (9 classes)
Layer 1	4	Clp (13 classes), Osi (2 classes), CppAD (2 classes), qpOASES (3 classes)
Layer 2	4	Cbc (4 classes), Cgl (6 classes), Ipopt (1 class), ADOL-C (1 class)
Layer 3	10	BCP (125 files), Bonmin (35 files), Couenne (32 files), Dip (1 class)
Layer 4	8	SHOT (15 classes), HiGHS (5 classes), Gravity (1 class)

Total: 28 libraries, 185 classes documented, 192 algorithm-annotated files, ~600 headers indexed

Using the Source Browser

All 30 libraries are indexed in the Source Browser, which provides:

File tree navigation across all layers
Header listings with class information
Quick links to documented classes
Search across the entire codebase

The browser loads data from the JSON API, making it easy for both humans and AI agents to explore the codebase structure.