Experiences in Developing HPC Software with Portable Efficiency

This contribution is concerned with software engineering for HPC applications in the field of engineering with a focus on CFD. Our goals are general usability, maintainability, portability and of course high performance and high scalability. Usability is a key property to any application as it sets the bounds on the efficiency the user can work with it. Therefore, we focus on this aspect and show how it is entangled with the other goals.Engineering deals with the design of technical devices and their fine tuning. Increasingly efficient devices require highly sophisticated models. This does not only entail a high resolution but also multiple physical phenomena, complex geometries and different length and time scales to be considered. Simulation software in the field of engineering needs to address these requirements, including high performance to handle the large computational demands. This results in sophisticated applications, which are deployed in an increasingly complex machine environment and need to combine fast execution with involved implementations for large models.We share in this article experiences we made in the development of a general mesh based tool chain for engineering applications named APES and its deployment on HPC machines. Specifically we address on the one hand some software engineering concepts, how they are applied, where they can be neglected and which of them we deem especially important in the HPC context. On the other hand we point to shortcomings in the machine installations that require workarounds and break software engineering principles.