Sparse frequency domain input
Reuse of pre-allocated memory
Support of negative indexing for frequency domain data
Parallelization and acceleration are optional
Unified interface for calculations on CPUs and GPUs
Support of Complex-To-Real and Real-To-Complex transforms, where the full hermitian symmetry property is utilized
C++, C and Fortran interfaces
To allow for pre-allocation and reuse of memory, the design is based on two classes:
Grid: Allocates memory for transforms up to a given size in each dimension.
Transform: Is associated with a Grid and can have any size up to the Grid dimensions. A Transform holds a counted reference to the underlying Grid. Therefore, Transforms created with the same Grid share memory, which is only freed, once the Grid and all associated Transforms are destroyed.
The user provides memory for storing sparse frequency domain data, while a Transform provides memory for space domain data. This implies, that executing a Transform will override the space domain data of all other Transforms associated with the same Grid.
The creation of Grids and Transforms, as well as the forward and backward execution may entail MPI calls and must be synchronized between all ranks.