Update to Work with Eigen 5.0.0

[EricaCMitchell]

Description

Eigen 5.0.0 changes where version is located. Needs to find version header for Eigen 5.x.x and Eigen 3.x.x. Same change as Libint PR 395.

Details

• Changes FindEigen3.cmake to try finding version for Eigen 5.x.x in new file Eigen/Version or try finding version for Eigen 3.x.x in old location Eigen/src/Core/util/Macros.h
• Introduces macro EIGEN_HAS_CXX17, which is set if EIGEN_MAJOR_VERSION > 4
• Checks range and matrix dimensions before inheritance in EigenSparseTile
• Check if data is nullptr after inheritance in TensorInterface

[Copilot]

Pull request overview

This PR updates FindEigen3.cmake to support both Eigen 5.x and 3.x version detection, as the version header location changed in Eigen 5.0.0. However, the PR also includes several unrelated changes in test files.

Changes:

• Updated FindEigen3.cmake to check for version headers in both Eigen 5.x location (Eigen/Version) and Eigen 3.x location (Eigen/src/Core/util/Macros.h)
• Refactored constructors in tests/sparse_tile.h to use IIFE pattern for running assertions before member initialization
• Modified test in tests/expressions_impl.h to use a temporary variable instead of reusing the same array
• Fixed assertions in src/TiledArray/tensor/tensor_interface.h to check member variables instead of parameters
• Changed spacing around archive operators in tests/sparse_tile.h

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
cmake/modules/FindEigen3.cmake	Adds support for Eigen 5.x version header location with fallback to Eigen 3.x location
tests/sparse_tile.h	Refactors constructors to use IIFE pattern and modifies archive operator spacing
tests/expressions_impl.h	Changes test to use temporary variable for block operations
src/TiledArray/tensor/tensor_interface.h	Fixes assertions to check member variables after initialization

Comments suppressed due to low confidence (1)

cmake/modules/FindEigen3.cmake:54

• After reading the version header file, if the regex matches fail (lines 47-52), the version variables (EIGEN3_WORLD_VERSION, EIGEN3_MAJOR_VERSION, EIGEN3_MINOR_VERSION) will be empty strings. This could lead to an incorrect EIGEN3_VERSION being set on line 54 (e.g., "..") and potentially unexpected behavior in version comparison on line 55. Consider adding validation after the regex matches to ensure the version numbers were successfully extracted, or set EIGEN3_VERSION_OK to FALSE if any of the version components are empty.

  string(REGEX MATCH "define[ \t]+EIGEN_WORLD_VERSION[ \t]+([0-9]+)" _eigen3_world_version_match "${_eigen3_version_header}")
  set(EIGEN3_WORLD_VERSION "${CMAKE_MATCH_1}")
  string(REGEX MATCH "define[ \t]+EIGEN_MAJOR_VERSION[ \t]+([0-9]+)" _eigen3_major_version_match "${_eigen3_version_header}")
  set(EIGEN3_MAJOR_VERSION "${CMAKE_MATCH_1}")
  string(REGEX MATCH "define[ \t]+EIGEN_MINOR_VERSION[ \t]+([0-9]+)" _eigen3_minor_version_match "${_eigen3_version_header}")
  set(EIGEN3_MINOR_VERSION "${CMAKE_MATCH_1}")

  set(EIGEN3_VERSION ${EIGEN3_WORLD_VERSION}.${EIGEN3_MAJOR_VERSION}.${EIGEN3_MINOR_VERSION})

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[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 4 comments.

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[EricaCMitchell]

Eigen3 5.x.x makes a change in its allocation if size == 0 (libeigen L217) compared to Eigen3 4.x.x.

For an empty TiledRange1, this results in a nullptr being returned instead of the previous static_cast<pointer>(std::malloc(0)), which screws up the data_ in tensor.h.