Add kokkos-fft link and Kokkos Kernels reference

Author: tpadioleau

paper/paper.bib

@@ -94,3 +94,10 @@ @article{grandgirard2016
 url = {https://www.sciencedirect.com/science/article/pii/S0010465516301230},
 author = {V. Grandgirard and J. Abiteboul and J. Bigot and T. Cartier-Michaud and N. Crouseilles and G. Dif-Pradalier and Ch. Ehrlacher and D. Esteve and X. Garbet and Ph. Ghendrih and G. Latu and M. Mehrenberger and C. Norscini and Ch. Passeron and F. Rozar and Y. Sarazin and E. Sonnendrücker and A. Strugarek and D. Zarzoso},
 }
+
+@article{rajamanickam2021kokkos,
+ author = {Rajamanickam, Sivasankaran and Acer, Seher and Berger-Vergiat, Luc and Dang, Vinh and Ellingwood, Nathan and Harvey, Evan and Kelley, Brian and Trott, Christian R and Wilke, Jeremiah and Yamazaki, Ichitaro},
+ journal = {arXiv preprint arXiv:2103.11991},
+ title = {Kokkos Kernels: Performance Portable Sparse/Dense Linear Algebra and Graph Kernels},
+ year = {2021}
+}

paper/paper.md

@@ -53,7 +53,7 @@ Many programming languages commonly used in scientific computing support multidi
 
 Despite their importance, multidimensional arrays introduce several practical challenges. In a sense, they encourage the usage of implicits in the source code. A frequent source of errors is the inadvertent swapping of indices when accessing elements. Such errors can be difficult to detect, especially given the common convention of using single-letter variable names like `i` and `j` for indexing. Another challenge in medium to large codebases is the lack of semantic clarity in function signatures when using raw multidimensional arrays. When array dimensions carry specific meanings, this information is not explicitly represented in the source code, leaving it up to the user to ensure that dimensions are ordered correctly according to implicit expectations. For example it is quite usual to use the same index for multiple interpretations: looping over mesh cells identified by `i` and interpreting `i+1` as the face to the right. Another example is slicing that removes dimensions, this operation may change the relative ordering of dimensions.
 
-Solutions have been proposed in Python and Julia to address these issues. In Python, the Xarray [@hoyer2017xarray] and Pandas [@reback2020pandas] libraries allow users to label dimensions that can then be used to perform computations. Following a similar approach, the "Discrete Domain Computation" (DDC) library aims to bring equivalent functionality to the C++ ecosystem. It uses a zero overhead abstraction approach, i.e. with labels fixed at compile-time, on top of different performant portable libraries, such as: Kokkos [@9485033], Kokkos Kernels (TODO: add a citation), Kokkos-fft (TODO: add a citation) and Ginkgo [@GinkgoJoss2020].
+Solutions have been proposed in Python and Julia to address these issues. In Python, the Xarray [@hoyer2017xarray] and Pandas [@reback2020pandas] libraries allow users to label dimensions that can then be used to perform computations. Following a similar approach, the "Discrete Domain Computation" (DDC) library aims to bring equivalent functionality to the C++ ecosystem. It uses a zero overhead abstraction approach, i.e. with labels fixed at compile-time, on top of different performant portable libraries, such as: Kokkos [@9485033], Kokkos Kernels [@rajamanickam2021kokkos], [kokkos-fft](https://github.com/kokkos/kokkos-fft) and Ginkgo [@GinkgoJoss2020].
 
 The library is actively used to modernize the Fortran-based Gysela plasma simulation code (TODO: add a citation). This simulation code relies heavily on high-dimensional arrays that span multiple representations, including Fourier, spline, Cartesian, and various curvilinear meshes. In the legacy Fortran implementation, these arrays were manipulated using implicit conventions, making it difficult to enforce correctness at the API level. DDC enables a more explicit, strongly-typed representation of these arrays, ensuring at compile-time that function calls respect the expected dimensions. This reduces indexing errors and improves code maintainability, particularly in large-scale scientific software.