Visualization and Data Analysis using VisIt - In Situ Visualization - - PowerPoint PPT Presentation

July 8., 2016 Folie 1 VisIt Workshop

Mitglied der Helmholtz-Gemeinschaft

Visualization and Data Analysis using VisIt

• In Situ Visualization -

Jens Henrik Göbbert1, Herwig Zilken1

1 Jülich Supercomputing Centre, Forschungszentrum Jülich GmbH, Germany

Application Support, Cross-Sectional-Team „Visualization“ {j.goebbert, h.zilken}@fz-juelich.de

VisIt Workshop

July 8., 2016 Folie 2 VisIt Workshop

Motivation

why not stick to the established workflow Application CIAO on JUQUEEN (specific setup)

■

Excellent scaling of solver

■

File writing dumping output is bottleneck at scale dump simulation data with high temporal resolution not possible

July 8., 2016 Folie 3 VisIt Workshop

In Situ Visualization

visualization for large-scale simulations … post visualization Visualization of simulation data in a post processing step requires to write and then read files, paying for I/O twice in different application. … in situ visualization

• visualization capabilities inside the simulation
• avoid I/O
• compression method

July 8., 2016 Folie 4 VisIt Workshop

Motivation

lowering the barriers to in-situ visualization Major barriers to in situ visualization are … … first,

• the individual implementation-, optimization- and coupling-costs

to integrate the needed functionality to each simulation code and setup can often not be justified. … second,

• the usage of in situ visualization requires much training for scientists

who's research work in general does not focus on visualization in the first place. Lowering the barriers to in-situ visualization

July 8., 2016 Folie 5 VisIt Workshop

Applications

coupled with VisIt/Libsim … psOpen

• flow solver (LES, DNS)
• multiphysics, multiscale
• finite volume method
• lattice-Boltzmann method
• discontinuous Galerkin method
• level-set for surface tracking
• Lagrangian particle solver
• Institute of Aerodynamics Aachen

RWTH Aachen University, Germany

• C++11 + MPI + OpenMP + GPU

… CIAO … ZFS

• flow solver (LES, DNS)
• multiphysics, multiscale
• structured finite difference method
• level-set for surface tracking
• level-set/volume-of-fluid interface
• Lagrange particle solver
• tabulated/finite rate chemistry
• overset mesh refinement
• moving meshes
• Institute for Combustion Technology

RWTH Aachen University, Germany

• Fortran90 + MPI
• JUQUEEN BigWeek participant
• flow solver (DNS)
• highly resolved turbulence
• pseudo-spectral approach
• Institute for Combustion Technology

RWTH Aachen University, Germany

• Chair of Num. Thermo-Fluid Dyn.

TU Freiberg, Germany

• Fortran90 + MPI + OpenMP
• JUQUEEN BigWeek participant

July 8., 2016 Folie 6 VisIt Workshop

Staged In Situ

„small“ compute node „big“ compute node HPC interconnect HPC file system

GPU GPU

interactive visualization node

• „small“ compute nodes für die Simulation
• „big“ compute nodes für die nachgelagerte Verarbeitung
• Visualisierung/Analyse der Rohdaten
• unmittelbares Rendering auf „big“ nodes mit OpenGL-fähigen GPUs

Pro: exklusive Hardwareresourcen für Simulation und nachgelagerte Verarbeitung Contra: Kopieren der Daten zwingend notwendig

July 8., 2016 Folie 7 VisIt Workshop

On-Node In-Situ

„small“ compute node HPC interconnect HPC file system

GPU

interactive visualization node

• „small“ compute nodes
• Simulation und Visualisierung/Analyse der Rohdaten

Pro: Kopieren von Daten zwischen Simulation und Datenverarbeitung entfällt Contra: keine exklusiven Hardwareresourcen für Simulation und Verarbeitung

July 8., 2016 Folie 8 VisIt Workshop

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Coupling of Simulation and Visualization/Analysis

Simulation Visualization Simulation Visualization Simulation In-Situ Framework Visualization „no coupling“ „tightly-coupling“ „loosly-coupling“

July 8., 2016 Folie 9 VisIt Workshop

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Tightly-Coupled In-Situ Visualization

July 8., 2016 Folie 10 VisIt Workshop

Scalable Rendering Mode

VisIt – parallelized client-server architecture

network connection

Parallel Cluster Local Components

(Files or Simulation)

VisIt

Engine

Data Plugin

VisIt

Engine

Data Plugin

MPI

Data Flow Network

Filter Filter Filter

Python Clients

Java Clients

VisIt

GUI

VisIt

CLI

VisIt

Viewer

Data Plugin

VisIt

Engine Data Data Data

July 8., 2016 Folie 11 VisIt Workshop

JUSITU

coupling simulation code to in-situ visualization

• sim. developer

simulation VisIt/ Libsim ParaView/ Catalyst

• vis. developer
• ne data adapter for each visualization tool
• need for reinventing infrastructure code for each simulation to couple
• responsibility for coupling code by sim. developer
• changes on the visualization software side only possible in close

cooperation with sim. developers

July 8., 2016 Folie 12 VisIt Workshop

JUSITU

coupling simulation code to in-situ visualization

• sim. developer
• vis. developer

simulation VisIt/ Libsim ParaView/ Catalyst JUSITU

• light-weighted, flexible and easy-to-use coupling library
• covers the complexity and numerous options of in-situ visualization
• simplifies communication between sim. developer and vis. developer
• written in C++ / MPI

July 8., 2016 Folie 13 VisIt Workshop

In Situ Visualization with VisIt/Libsim