src/NEWS

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    Release ‘25-02-26 (macros)’

    Macros in qcc and rewrite of grid implementations

    The preprocessor and the grid/* implementations have been rewritten using the new macro functionality. As a consequence the older macro definitions, typically using the syntax

    @def foreach_mymacro()
...
@
@define end_foreach_mymacro()

    will not work anymore and need to be rewritten using the simpler/cleaner/better new syntax.

    In the same context, the special map() macros, used in the previous implementation for coordinate mapping are now obsolete. See spherical.h for an example on how to use the new macro inheritance feature to implement this mapping.

    Similarly expressions using

    Point point = ...;

    which have caused ‘obsolete’ warnings for a while, will now trigger an error. They should be replaced with foreach_point/foreach_region which are compatible with reductions, GPUs etc.

    The solve() macro has been rewritten using the new macro functionality and is now a return macro i.e. its syntax has changed.

    Generalised support for GPUs

    Most of the rewrite above was motivated by a better integration of GPUs. Several important test cases and examples now run on GPUs including:

    New benchmarks results were done on a high-end “gamers” graphics card RTX4090: performances for realistic applications (e.g. the Gulf Stream) of a single RTX4090 card are comparable to that of the 768 AMD cores of the cluster at d’Alembert.

    Non-square/cubic domains on multigrids

    It was previously possible to define non-square/cubic domains only when using grid/multigrid and MPI. This now works also in OpenMP/serial and on GPUs. See the updated Tips.

    Note also that all “dimensions/aspect ratios” must now be specified (previously some dimensions were automatically guessed by the MPI topology layout engine): this change was made because the previous behaviour could cause confusion (i.e. the aspect ratio could change when one was not careful to use the appropriate number of MPI processes).

    Flexible homogeneous boundary conditions

    The definition of “homogeneous” versions of boundary conditions is now flexible (previously it required modification of the AST qcc engine). See Basilisk C documentation.

    Other changes