SC21 SENSEI-Ascent Tutorial 2021 – In Situ Analysis and Visualization with SENSEI and Ascent



  • E. Wes Bethel (LBNL)
  • Cyrus Harrison (LLNL)
  • Matt Larsen (LLNL)
  • Burlen Loring (LBNL)
  • Silvio Rizzi (ANL)
  • Terry Turton (LANL)


A key trend facing extreme-scale computational science is the widening gap between computational and I/O rates. A remedy known as in situ processing targets performing as much processing with the data while still resident in memory, thereby avoiding costly I/O. Current efforts in the HPC community produce several production tools for in situ processing with emphasis on scientific use cases on current and future HPC platforms. This tutorial blends lectures and hands-on examples to introduce attendees to in situ processing concepts and provide practical experience using state-of-the-art in situ tools, including: SENSEI, Ascent, ParaView Catalyst, VisIt Libsim, and Cinema. Attendees will learn how to use the SENSEI and Ascent in situ interfaces to couple simulation codes to multiple endpoints. This tutorial is ideal for those who would like to learn how to analyze, visualize, or process data on HPC platforms while it is still resident in memory.


Getting Started

  • Introduction and Overview (Bethel, 20min)
  • SENSEI VM setup (Loring, 10 min)


  • Overview (Loring, 20 min)
  • Hands on demonstrations (Loring, 20 min)
  • SENSEI + LAMMPS molecular dynamics code demo (Rizzi, 20 min)



  • Overview and demonstration (Harrison and Larsen, 60 min)

Post-hoc exploration of images computed in situ

  • Cinema (Turton, 25 min)

Wrap-up (Bethel, 5 min)

Extended Q&A (all, 30 min)


Links to VMs, containers, handouts, etc. (work in progress )