Add specialization for compile-time zero-sized dense assignment.

In the current `dense_assignment_loop` implementations, if the
destination's inner or outer size is zero at compile time and if the kernel
involves a product, we currently get a compile error (#2080).  This is
triggered by attempting to multiply a non-existent row by a column (or
vice-versa).

To address this, we add a specialization for zero-sized assignments
(`AllAtOnceTraversal`) which evaluates to a no-op. We also add a static
check to ensure the size is in-fact zero. This now seems to be the only
existing use of `AllAtOnceTraversal`.

Fixes #2080.
1 file changed
tree: 45f7551c781d7351135e2fdd19d13f998352a711
  1. bench/
  2. blas/
  3. ci/
  4. cmake/
  5. debug/
  6. demos/
  7. doc/
  8. Eigen/
  9. failtest/
  10. lapack/
  11. scripts/
  12. test/
  13. unsupported/
  14. .gitignore
  15. .gitlab-ci.yml
  16. .hgeol
  17. CMakeLists.txt
  18. COPYING.APACHE
  19. COPYING.BSD
  20. COPYING.GPL
  21. COPYING.LGPL
  22. COPYING.MINPACK
  23. COPYING.MPL2
  24. COPYING.README
  25. CTestConfig.cmake
  26. CTestCustom.cmake.in
  27. eigen3.pc.in
  28. INSTALL
  29. README.md
  30. signature_of_eigen3_matrix_library
README.md

Eigen is a C++ template library for linear algebra: matrices, vectors, numerical solvers, and related algorithms.

For more information go to http://eigen.tuxfamily.org/.

For pull request, bug reports, and feature requests, go to https://gitlab.com/libeigen/eigen.