boltzgen - Symbolic generation of LBM kernels

Age	Commit message (Collapse)	Author
2019-11-10	Implement basic CUDA target	Adrian Kummerlaender
	Currently only for the SSS streaming pattern. CudaCodePrinter in `utility/printer.py` is required to add a 'f' suffix to all single precision floating point literals. If this is not done (when targeting single precision) most calculations happen in double precision which destroys performance. (In OpenCL this is not necessary as we can simply set the `-cl-single-precision-constant` flag. Sadly such a flag doesn't seem to exist for nvcc.)
2019-11-09	Implement basic version of the SSS pattern for C++ target	Adrian Kummerlaender
	An interesting extension of the AA pattern. The main advantage of this is that updating pointers in a control structure is much more elegant than duplicating all function implementations as is required by the normal AA pattern. For more details see [1]. Only works for the SOA layout. On a pure memory access level this pattern is equivalent to the AA pattern. The difference is how the memory locations are calculated (by pointer swap & shift or by different indexing functions for odd and even time steps). [1]: "An auto-vectorization friendly parallel lattice Boltzmann streaming scheme for direct addressing" by Mohrhard et al. (2019)