The Astrophysical MUltiscale Software Environment (AMUSE)

P-I: Portegies Zwart

Co-Is: Nelemans, Pols, O’Nuallain, Spaans

Adv.: Langer, Tolstoy, Hut, Ercolano, de Grijs, Mellema, Spurzem, Bischof, Quillen

AMUSE

The objectives of AMUSE

More science with existing software

Combine existing astrophysical codes

This is a technical problem

It is technically possible

Impression of how it works

Existing codes

Excellent single-physics codes exist hydro

gravity

radiation

stellar evolution

All written in different languages, different format, different architecture....

Need a homogeneous environment for utilizing these resources

More science with existing code Universe is multi-physics ...

Scientific objectives: dense stellar systems (hydro+gravity+stellar evo.)

evolution of galactic environments, star formation, AGN, ... (hydro+gravity+radiation)

planet formation (hydro+gravity+radiation)

galaxy formation and interaction (gravity+hydro+radiation+stellar evo.)

Single physics software solutions exist, try to combine existing codes

This is a technical problem

No new physics needed

Combining requires understanding of how software and computer hardware interacts

Development to a usefull toolbox requires professional engineering

Requires substantial manpower

It is technically feasible

Developing new code not optimal because it is a time consuming task

large codes tend to become unmanageable

initial assumptions tend to require redesign at a late stage in the development process

Combining existing code via wrapper has been tried, and works

Propose homogeneous software framework, à la Numerical Recipes

Flow control layer (scripting language)

Gas dynamicsRadiative transport

Stellar evolution Stellar dynamics

Interface layer (scripting and high level languages)

Smoothed particles

hydrodynamics

MetropolisHastings

Monte Carlo

Henyeymulti-shell

stellar evolution

4th order Hermiteblock timestep

N-body

AMUSE

Limitations and Merits

- Only problems whose physics are expressible through module coupling (different time scales)

- Low and high level use possible

- Radiative transfer (and stellar evolution) module links to VO (through eg. ‘spiegel’ and ‘partiview’): dust and stellar continuum, atomic and molecular lines; ELT, JWST, ALMA, Herschel

Impression of how it works

A) install

B) suite of test applications

C) design your own multi-physics problem

D) write script

E) run

F) analyze data

G) download package from website

H) write Nature paper

Design/Performance

AMUSE module must be written in language with Foreign Function Interface (C, C++, Fortran as well as high level languages like C#, Java, Haskell. Low level applications optimized.

Top level uses a scripting language. These are slow, but do just I/O, GUI, call sequence.

Top level can run in parallel (using MPI, GRID technology); data exchange through HDF

Low level can run in parallel or on dedicated hardware (eg GRAPE or GPU for direct N-body)

Initial Applications

Young and dense star cluster

Evolution of gas and stars near a black hole in a galactic nucleus

Dynamics of embryonic planets in a debris disk

Relation to other projects Different concept but with similar scientific

objectives/physics: FLASH

Gadget

Starlab

Comparable in setup but with different scientific objectives: Atmosphere/Ocean/Tectonic

simulations by NASA

Molecular dynamics

QUESTIONS?

management/development plan

programmers under daily supervision of software engineer and PI

regular interaction with postdoc, who protects scientific objectives

The cost

6-year of programming effort (3x2years?)

2 years of software engineering

2 years of postdoc

travel, webservices, hardware, etc.

total cost: 640Keuro

NOVA request: 500kEuro