Abstract: Developers who build research software for High Performance Computing (HPC) or High Performance Data Analysis/Analytics (HPDA) face software engineering (SE) challenges at scales not often addressed by traditional SE approaches. For example, HPC and HPDA software developers must solve reliability, availability, and maintainability problems at extreme scales, consider reproducibility, understand domain specific constraints, deal with uncertainties inherent in scientific exploration, and efficiently use compute resources. SE researchers have developed tools and practices to support development tasks, including: requirements, design, validation and verification, testing, continuous integration, and maintenance. Because of the scale of HPC and HPDA, there is a need to adapt these SE tools/methods that are standard elsewhere. This workshop brings together members of the SE and HPC/HPDA communities to present findings relative to these problems and to generate an agenda to advance software engineering tools and practices for HPC/HPDA software.