Kutalmış Berçin authored 5 years ago and Andrew Heather committed 5 years ago

  - `tensor` and `tensor2D` returns complex eigenvalues/vectors
  - `symmTensor` and `symmTensor2D` returns real eigenvalues/vectors
  - adds new test routines for eigendecompositions
  - improves numerical stability by:
    - using new robust algorithms,
    - reordering the conditional branches in root-type selection

- change contiguous from a series of global functions to separate
  templated traits classes:

    - is_contiguous
    - is_contiguous_label
    - is_contiguous_scalar

  The static constexpr 'value' and a constexpr conversion operator
  allow use in template expressions.  The change also makes it much
  easier to define general traits and to inherit from them.

  The is_contiguous_label and is_contiguous_scalar are special traits
  for handling data of homogeneous components of the respective types.

Applied to eigen-value calculations. Fixed repeated-eigen-value issues
in eigen-vector generation.

This reverts commit c5bea524.

This reverts commit b18f6cc1.

- DynamicList gets append methods as per List
- misc cosmetic changes

- grammar in comments, namespace qualifiers, etc.