Modernize C++ to C++17: enum class, unique_ptr, constexpr, dead code removal

[ardiloot]

Summary

Modernize the C++ codebase from C++11 to C++17 with corresponding Cython binding updates. All 601 tests pass.

Changes

Build system (setup.py)

• Upgrade from -std=c++11 to -std=c++17 (Linux/macOS) and add /std:c++17 (Windows MSVC)
• Guard -msse3 flag behind x86 architecture check for ARM compatibility
• Remove force=True from cythonize()

C++ modernization (Common.h/cpp)

• typedef → using aliases (dcomplex, Tensor3d, pairdd)
• const → constexpr for compile-time constants; inline const for constI (non-literal type)
• Convert 6 enums to enum class: WaveDirection, NonlinearProcess, Polarization, NonlinearTmmMode, TMMParam, TMMParamType
• Add ENUM_CLASS_CYTHON_COMPAT macro providing operator|, operator<<, operator* for Cython interop
• Move WlToOmega, OmegaToWl, sqr to constexpr/inline in header
• Use const& for ApplyRotationMatrixToTensor parameters

C++ modernization (NonlinearLayer, NonlinearTMM, Waves, SecondOrderNLTMM)

• Qualify all enum values with their enum class scope throughout
• Use constexpr int iF/iB pattern for Array2cd indexing with enum class values
• Convert 8 factory functions to return std::unique_ptr
• Replace internal new/delete with stack allocation or make_unique
• Replace NULL with nullptr throughout
• Remove dead code: cerr before throw, break after return/throw

Bug fix

• pB was never initialized in NonlinearLayer.cpp (line was duplicating pF = Vector3cd::Zero())

Cython updates (.pxd/.pyx)

• Add unique_ptr import from libcpp.memory
• Update all enum string aliases for enum class qualification
• Add .release() to 8 unique_ptr call sites
• Update 8 return type declarations to unique_ptr[T]

Line endings

• Normalize all text files from CRLF to LF per .gitattributes

[Copilot]

Pull request overview

This pull request modernizes the C++ codebase from C++11 to C++17 standard with comprehensive updates to improve code quality and safety. The changes include upgrading compiler flags, converting traditional enums to enum classes, replacing raw pointers with unique_ptr, modernizing type aliases, and making appropriate use of constexpr. The PR also fixes a bug where pB was never initialized in NonlinearLayer.cpp and removes dead code. All 601 tests pass.

Changes:

• Build system upgraded to C++17 with ARM compatibility improvements
• Six enums converted to enum class with Cython interop macro
• Eight factory functions converted to return std::unique_ptr for better memory safety
• Type aliases modernized from typedef to using, constants upgraded to constexpr

Reviewed changes

Copilot reviewed 13 out of 49 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
setup.py	Upgraded C++ standard to C++17, added ARM architecture detection for SSE3 flag, removed force=True from cythonize
Common.h/cpp	Converted type aliases, constants to constexpr, enums to enum class, added ENUM_CLASS_CYTHON_COMPAT macro
NonlinearTMM.h/cpp	Updated return types to unique_ptr, qualified enum values, removed dead code
NonlinearLayer.h/cpp	Fixed pB initialization bug, qualified enum values with scope
Waves.h/cpp	Converted WaveType to enum class, updated function signatures
SecondOrderNLTMM.h/cpp	Updated return types to unique_ptr, qualified enum values
Material.h/cpp	Line ending normalization only
CppSecondOrderNLTMM.pxd	Added unique_ptr import, updated enum string aliases for enum class qualification
SecondOrderNLTMM.pyx	Added .release() calls for unique_ptr returns
Python files	Line ending normalization only
Test files	Line ending normalization only
Documentation files	Line ending normalization only

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