No changes w.r.t. v1.3.1 and v1.3 in terms of agglomeration algorithm. However, some important changes have been introduced in the structure and handling of the project:

• Add dedicated namespace comma
• Add choice of special types (for indices, standard integers, and reals) during configuration stage
• Move headers into include/CoMMA and sources into src
• Avoid using using namespace foo;
• Add ctidy
• [CI] Add tests for 32- and 64bit integer support and for pkgconfig support, and stages for format and linting (both for C++ and python files)

No major changes wrt v1.3. This version only improves the building process. For instance, a make install target is available which installs the headers (and python and documentation if requested) in the given prefix. Support for pkg-config has been added.

Changelog:

• Fixes and improvements for correction
• Restructure tests into small units
• Clean and improve examples

This version has been registered to the Agency for the Protection of Programs (APP), Paris, with IDDN identification number IDDN.FR.001.420013.000.S.X.2023.000.31235

This version brings two major improvements:

• Anisotropic lines: the growth direction is checked before including a new cell. Moreover, when agglomerating, user can choose whether to have or not 3-cells agglomerates if lines have odd length
• (Drastic) Performance improvements: anisotropic lines build and correction stage have been restructured. Moreover, the subgraphs of coarse cells are not build anymore. The improvements are significant: test on a series of 2D RAE meshes showed that, see plots below, we switch from an exponential (cf baseline picture, notice log scaling) to a linear one (cf improved) wrt to number of cells.

Case description for the performance tests: 2D RAE mesh with a quad BL and triangles elsewhere. Anisotropic agglomeration enabled with an anisotropic threshold of 2 and subset of compliant cells those around the airfoil (inside a given radius). Three arguments configurations tested:

RAE.1: Cardinality fixed to 4 (min=goal=max), no corrections
RAE.2: Cardinality between 2 and 6, no corrections
RAE.3: Cardinality fixed to 4, corrections enabled

This release brings several salient changes:

• Improve seeds pool handling and add some user option to control the order
• Consider user-defined priority weights used to compute the order of the seeds
• Consider cell centres to better evaluate the aspect-ratio
• Make isotropic and anisotropic agglomeration numbering deterministic
• Add iterative algorithm for the choice of the FC to agglomerate
• Improve anisotropic algorithm (update seeds pool, start from line end with higher boundary faces,...)
• Add full support for unsigned types and switch index type to unsigned
• Improve correction step
• Improve memory management (avoid copies, set parameters to const,...)
• Revisit neighbourhood handling