C++ Conventions

This document covers C++ coding conventions for Antares-Xpansion.

Language Standard

• C++20 is required
• GCC >= 11 (required for Intel TBB compatibility)

Code Style

Formatting

Use .clang-format with Chromium-based style:

clang-format -i -style=file <file>.cpp

Disable formatting for specific sections:

// clang-format off
// code here will not be reformatted
// clang-format on

Style Rules

• No comments unless explaining complex algorithms
• Use nullptr instead of NULL
• Use std::array or std::vector instead of C-style arrays
• Use const wherever possible
• Use [[nodiscard]] attribute for functions that must return a value
• Use override keyword when overriding virtual functions

Naming

• Classes: PascalCase (e.g., BendersSolver)
• Public member functions: PascalCase (e.g., InitializeSolver)
• Private member functions / helper functions: snake_case (e.g., initialize_solver)
• Variables: snake_case (e.g., iteration_count)
• Constants: UPPER_SNAKE_CASE (e.g., MAX_ITERATIONS)
• Private members: snake_case_ (trailing underscore)

Include Order

1. Project headers (quoted)
2. Standard library
3. External libraries (angled)

#include "benders/benders_core/BendersOptions.h"
#include "antares-xpansion/xpansion_interfaces/ILogger.h"
 
#include <vector>
#include <memory>
 
#include <boost/mpi.hpp>

Project Structure

src/cpp/
├── benders/                  # Benders decomposition algorithm
├── core/                     # Core shared utilities
├── exe/                      # Executable entry points
├── full_run/                 # Full run orchestration
├── helpers/                  # Shared helpers
├── lpnamer/                  # Generation of investment problems from simulation ones
├── merge_weights_trajectory/ # Trajectory weight merging
├── multisolver_interface/    # Solver abstraction layer
├── presolve/                 # Pre-solve logic
├── sensitivity/              # Sensitivity analysis
├── study-updater/            # Study updater
└── xpansion_interfaces/      # Public interfaces

Header Organization

• Each class in its own header file
• Use include guards (or #pragma once)
• Group related functionality into subdirectories

Dependencies

External Libraries

• Boost: MPI, serialization, program_options
• Coin-OR: Clp, Cbc, Cgl, CoinUtils, Osi
• JSON: jsoncpp
• MPI: OpenMPI
• TBB: Intel Threading Building Blocks

Finding Dependencies

The project uses CMake with vcpkg. Most dependencies are handled automatically.

Error Handling

• Use exceptions for unrecoverable errors
• Prefer std::optional for functions that may not return a value

Performance

• Avoid unnecessary copies (use const references)
• Use move semantics where appropriate
• Consider lazy evaluation for expensive operations
• Profile before optimizing

Logging

Use the project's logging infrastructure:

#include "antares-xpansion/xpansion_interfaces/ILogger.h"
 
// In class constructor
ILogger::Ptr logger_ = ...;
logger_->log_at_initialization("message");