Connecting many thousands of powerful, and possibly heterogeneous, multicore and accelerator based nodes using a high-performance interconnect leads to truly massive parallel systems with a tremendous performance potential. A state-of-the-art resource for the Swedish e-Science is the Kebnekaise system at HPC2N, which in addition to multi-core compute nodes, includes extremely large memory nodes (3TB per node) and nodes with accelerators (Nvidia GPU and Intel KNLs). This evolution makes it possible to solve even more complex and large-scale computational problems in science and engineering. At the same time, there is an immense demand for new and improved scalable, efficient, and reliable numerical algorithms, library software, and tools. This is essential, so that computations are carried out in a reasonable time and with the accuracy and resolution required.