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 dynamics Radiative transport Stellar evolutionStellar dynamics Interface layer (scripting and high level languages) Smoothed particles hydrodynamics Metropolis Hastings Monte Carlo Henyey multi-shell stellar evolution 4 th order Hermite block 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