High-performance multi-user code High-performance multi-user code development with Google Codedevelopment with Google Code

Current status

(...just google for Pencil Code)

PencilPencilcodecode

• Started in Sept. 2001 with Wolfgang Dobler• High order (6th order in space, 3rd order in time)• Cache & memory efficient• MPI, can run PacxMPI (across countries!)• Maintained/developed by ~40 people (SVN)• Automatic validation (over night or any time)• 0.0013 s/pt/step at 10243 , 2048 procs• http://pencil-code.googlecode.com

• Isotropic turbulence– MHD, passive scl, CR

• Stratified layers– Convection, radiation

• Shearing box– MRI, dust, interstellar– Self-gravity

• Sphere embedded in box– Fully convective stars– geodynamo

• Other applications– Chemistry, combustion– Spherical coordinates

Scaling Scaling propertiesproperties

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Wlad Lyra on Kraken Babkovskaia et al (2011)

PencilPencilCodeCode

• Started in Sept. 2001 with Wolfgang Dobler• High order (6th order in space, 3rd order in time)• Cache & memory efficient• MPI, can run PacxMPI (across countries!)• Maintained/developed by ~40 people (SVN)• Automatic validation (over night or any time)• Max resolution so far 10243 , 4096 procs• http://pencil-code.googlecode.com

• Isotropic turbulence– MHD, passive scl, CR

• Stratified layers– Convection, radiation

• Shearing box– MRI, dust, interstellar– Self-gravity

• Sphere embedded in box– Fully convective stars– geodynamo

• Other applications– Homochirality– Spherical coordinates

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Google Code webpageGoogle Code webpage

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Continuous updates onlineContinuous updates online

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Automatic validation testsAutomatic validation tests

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Evolution of code sizeEvolution of code size

User meetings:User meetings:2005 Copenhagen2006 Copenhagen2007 Stockholm2008 Leiden2009 Heidelberg2010 New York2011 Toulouse2012 Helsinki

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Increase in # of auto testsIncrease in # of auto tests

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Regularity of check-insRegularity of check-ins

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More check-ins since 2010More check-ins since 2010

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Return to previous rateReturn to previous rate

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TutorialTutorial

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Tut

oria

l pag

esT

utor

ial p

ages

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OlholOlhol

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Olhoh.net analysisOlhoh.net analysis

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CreditCredit

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Free licence, but giving credit to researchFree licence, but giving credit to research

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Faster and bigger machinesFaster and bigger machines

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256 processor run at 1024256 processor run at 102433

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Hyperviscous, Smagorinsky, normalHyperviscous, Smagorinsky, normal

Inertial range unaffected by artificial diffusionHau

gen

& B

rand

enbu

rg (

PR

E, a

stro

-ph/

0402

301)

height of bottleneck increased

onset of bottleneck at same position

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Online data reduction and visualizationOnline data reduction and visualization

non-helically forced turbulence

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Scalars on periphery of the boxScalars on periphery of the box

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MRI turbulenceMRI turbulenceMRI = magnetorotational instabilityMRI = magnetorotational instability

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w/o hypervisc.t = 600 = 20 orbits

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w/o hypervisc.t = 60 = 2 orbits

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Vorticity and DensityVorticity and Density

See poster by Tobi Heinemann on density wave excitation!

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Transfer equation & parTransfer equation & paraallelizationllelization

Analytic Solution:

Ray direction

Intrinsic Calculation

Processors

SII

d

d

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The Transfer Equation & The Transfer Equation & ParParaallelizationllelization

Analytic Solution:

Ray direction

Communication

Processors

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The Transfer Equation & The Transfer Equation & ParallelizationParallelization

Analytic Solution:

Ray direction

Processors

Intrinsic Calculation

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Future developmentsFuture developments

• Adaptive/multiple mesh

• More 3-D online graphics output

• Poisson solver for non-Cartesian geometries

• Parallel developments with graphics card