The Jungle Universe About scales and physics in the cosmos Simon - - PowerPoint PPT Presentation

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The Jungle Universe About scales and physics in the cosmos Simon - - PowerPoint PPT Presentation

Aug 19, 2023 126 likes •584 views

The Jungle Universe About scales and physics in the cosmos Simon Portegies Zwart Sterrewacht Leiden Observation of the early universe (WMAP) Abel1689 Stephen's quintuplet The universe is multi-physics The universe is multi-scale Jungle

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The Jungle Universe

About scales and physics in the cosmos Simon Portegies Zwart Sterrewacht Leiden

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Observation of the early universe (WMAP)

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Abel1689

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Stephen's quintuplet

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The universe is multi-physics

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The universe is multi-scale

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Jungle scales

Size scale covers anythin from:

  • 13.8 billion light years to km-size
  • that covers 24 orders of magnitude
  • 13.8 billion years to seconds
  • that covers 18 orders of magnitude
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D u Dt = F− ∇ p ρ ν ∇

2

u

( )u

u t u Dt u D     ∇ ⋅ + ∂ ∂ =

= ⋅ ∇ u 

) , , ( 4 ) , , ( ) , , ( ) , , ( ) , , ( 4 1 4

2 2 4 i i grav i i nuc i

Y T P P r GmT m T Y T P Y T P Y T P m L Y T P r m r r Gm m P

∇ − = ∂ ∂ + + = ∂ ∂ = ∂ ∂ − = ∂ ∂ π ε ε ε ρ π π

ν

F = G m1 m2

r 2

) (ν

ν ν

k j S =

ν ν ν

τ S I d dI

s

+ − =

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Sir Arthur Eddington Sir Isaac Newton Cloude-Louise Navier George Gabriel Stokes Subrahanyan Chandrasekhar James Clark Maxwell

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Abacus (500BC, compute speed ~10FLOP) Sumerian cuneform clay tablet dated around 1,200BC explaining the periodic behavior the planet Venus around 1,600BC (compute speed ~ 1 FLOP)

Prehistoric computational astrophysics

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”...'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able rightly to apprehend the kind

  • f confusion of ideas that could provoke

such a question."

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Jun & GRAPE-4 von Neuman & IAS

~30 000 000 times faster

500BC 2003 1960

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Stellar evolution Gravity gas-dynamics hydro-dynamics Radiative transport Maxwell equations

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DAS-4 LGM

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Computational challenges

  • High performance (desktop) computing
  • Distributed (wide area) computing
  • Problem solving environments (software)
  • Data acquisition
  • Data mining
  • Visualization
  • Virtual collaboration
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1908-2000

10mFlops

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Manchester mark1 (1948, 550 FLOPs)

Software by Tom Kilburn

Software operated computers

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The next generation problem solving environments

  • Specialization (higher resolution)
  • Optimization (high-performance)
  • Diversification (wide range of applications)
  • Hybridization (multi physics)
  • Preservation (containment of existing codes)
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The Astrophysical Multipurpose Software Environment AMUSE http://amusecode.org

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Scientific research and development team

  • Marco Spaans
  • Gijs Nelemans
  • Vincent Icke
  • Onno Pols
  • Lex Kaper
  • Steve McMillan
  • Paul Groot
  • Eline Tolstoy
  • Evert Glebbeek
  • Rien vd Weijgeart
  • Rob Knop
  • John Fregeau
  • Breanndan O Nuaillan
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AMUSE - philosophy

  • Build on community codes
  • Standarized interfaces
  • Automate as much as possible
  • Builds on lessons learned from previous generations
  • Core Team:

– Inti Pelupessy (post-doc) – Arjen van Elteren (software engineer) – Marcel Marosvolgi, Nathan de Vries (programmers) – David Jansen (user support)

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AMUSE - design

Gravity Hydrodynamics Stellar Evolution Radiative Transfer Unit handling Data conversion Initial conditions INPUT OUTPUT Compare models

AMUSE Combining existing codes With an extensive support framework To provide a generic framework For doing astrophysical experiments

www.amusecode.org

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Next Level Legacy Interfaces

AMUSE http://amusecode.org

C/C++ code Fortran Code MPI Message Channel RT GD HD SE Particles Python Script Units

  • Layers having different

roles

  • Written in C/C++, Java

Fortran and Python

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Pelupessy etal in prep

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User script Community code Message passing script Message passing source evolve() Send request Send request evolve() Confirm request Evolve() done Send answer Send request Confirm request Confirm request Confirm request Send answer

Process 1 Process 2

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Two examples

  • Formation of J1903+0327 (ApJ in press: ArXive:1103-2275)

– Gravitational dynamics + Stellar evolution

  • Evolution of young star cluster (to be submitted)

– Gravitational dynamics + Stellar evolution + Hydro

dynamics

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NGC3603 cluster By HST

Simulating Embedded star clusters

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Numerical ingredients

  • Gravitational dynamics

– Direct N-body integration (PhiGRAPE) – GPU or GRAPE equipped pc

  • Stellar evolution

– Henyey stellar evolution (MESA) – Beowulf computer cluster

  • Gas dynamics

– Smoothed particles hydrodynamics (Fi) – Super computer

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Evolution of a gas rich star cluster

SFE=0.05 ffb=0.1 SFE=0.50 ffb=0.01

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AMUSE Today

  • Automated referencing
  • Unit conversion
  • Online documentation
  • Suite of examples
  • Intricate module coupling via Hamiltonian

splitting

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Wish-list for AMUSE

  • Runtime crash-recovery
  • Self-consistent code restart
  • Initial conditions repository
  • Extensive data mining and analysis toolbox
  • High-performance AMUSE
  • AMUSE on the grid (PDRA Niels Drost VU)
  • Asynchronous communication support
  • Load balancing on heterogeneous architectures
  • Data tunneling protocol