ALPS Montreal

7/27/2019 ALPS Montreal

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The ALPS ProjectOpen Source Software forQuantum Lattice Models

Simon Trebst, ETH Z!rich

The ALPS co!aboratio"

http://alps.comp"phys.org


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The ALPS collaboration

University of Tokyo, Japan

Synge Todo

ETH Zrich, Switzerland

Fabien Alet

Prakash Dayal Mathias Krner

Guido Schmid

Simon Trebst

Matthias Troyer

Philipp Werner

Stefan Wessel

Universitt Marburg, Germany Reinhard Noack

Salvatore Manmana

Universitt Wrzburg, Germany

Martin Jstingmeier TU Braunschweig, Germany

Andreas Honecker

Universitt Bonn, Germany

Axel Grzesik

Universit de Toulouse, France Andreas Luchli

RWTH Aachen, Germany

Ulrich Schollwck

Ian McCulloch

TU Graz, Austria

Franz Michel

Hans-Gerd Evertz

Algorithms andLibraries forPhysicsSimulations


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The ALPS project open source libraries and simulation codes for strongly

correlated quantum systems

Quantum Monte Carlo exact diagonalization

DMRG

Motivation established algorithms

increased demand for reliable simulations fromtheorists and experimentalists


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Strongly correlated systems

compare microscopic models to experiments

0

2

4

6

8

10

12

0 200 400 600

experiment

simulation!

(10"

5c

m3/molC

u)

T (K)

SrCu2O

3

J'/kB= 929 K

J/kB

= 1904 K

simulation


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Strongly correlated systems

BEC of ultra"cold atoms in optical lattices

quickly test theoretical ideas

0 5 10 15 20

r / a

0.0

0.2

0.4

0.6

0.8

1.0

1.2

n(r

)

0.0

0.1

0.2

0.3

!local

(r

)

talk H28.004 by Stefan Wessel


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Simulation of

quantum lattice models The status quo

individual codes

model"speci#c implementations growing complexity of methods

ALPS

community codes generic implementations common libraries simplify code development common #le formats


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Modern technologies

!Starting late"allows us to use

generic programming in C++fast & $exible codes

standard C++libraries

MPI and OpenMP for parallelization XML / XSLT for #le processing


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The ALPS sources

schedulerlattice model observablesdomain speci#clibraries

QMC ED DMRGapplications ...

numerics random ublas IETL

C / Fortran MPILAPACKBLAS

general C++ XML/XSLTgraph serialization


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The ALPS lattice libraryA lattice


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A model

-h*Sz


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Simulations with ALPS

Lattice

...

Model

-h*Sz


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Open source development

of ALPS

Collaborative development Why open source codes?

License discussion

Funding situation


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The History

the dark ag#

QMC, basic libraries%94

loop code%97

%02

SSE%01

%03

ALPS

%04

%94DMRG


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Current applications Quantum Monte Carlo

stochastic series expansions &SSE', F. Alet, M. Troyer

loop code for spin systems, S. Todo continuous time worm code, S. Trebst, M. Troyer

Exact diagonalization

full and sparse,A. Honecker, A. L(uchli, M. Troyer

DMRG

single particle, S. Manmana, R. Noack, U. Schollw)ck

interacting particles, I. McCulloch


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Collaborative development

Some 15 developers, mostly PhDs.

technical infrastructure source code control system &CVS'

mailing lists

web page semi"annual workshops

Austria, France, Germany, Japan, Netherlands and Switzerland


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Developer workshops

Developers meet at semi"annual workshops

review of #nished projects discussion of current developments

road"map for new developmentsin the next 6 months

Workshop are essential to coordinate anddrive the development.


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Open source codes Why open source?

community pro#ts from improvements byindividual developers

e.g. adding disorder to models

simplify code development

build on lattice, model, ... libraries

non"experts can use sophisticated algorithms

reproducibility of published scienti#c results


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Open source codes

Why should a researcher publish his codes? start new collaborations / networks

name recognition

citations peer pressure to contribute

The !cite me"$license

scienti#c returnopen sources


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The *cite me+"license

Applications codes

free for non"commercial applications

based on GNU public license

citation requirements

Modi$cations / improvements ofcodes should be integrated into ALPS

not obligatory to publish


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The *cite me+"license

Applications codes

free for non"commercial applications

based on GNU public license

citation requirements

Library codes less restrictive

partially available under a free license


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User workshops

Oak Ridge %03

part of workshop on Wang"Landau sampling

Lugano %04

general lectures on numerical methods

hands"on tutorials of applications

direct feedback from users

workshops/tutorials set deadlines for developments


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Become a user yourself!http://alps.comp"phys.org


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Funding situation

Software development classi#ed as

infrastructure project no funding by research grants

combination with research projects no professional code developers


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Funding situation Funding sources for infrastructure

computer centers,

Swiss National Supercomputer CenterORNL

companies?

think big: group grantcan fund a software developer

open source development helpful

Calcolo Scientifico

Swiss Center for

Centro Svizzero di

Scientific Computing

CSC

S

SCSC


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Experiences

Advantages of open source development !

improved code design

more $exibility

code review by fellow developers

new collaborations, joint research projects !

new contacts to experimental groups !

more work "


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ALPS workshop %04Lugano, September 26 "October 1

Classical Monte Carlo

Spin DynamicsQuantum Monte CarloExact diagonalizationDMRG

F. Alet

G. BrownH."G. EvertzC. KollathA. L(uchliI. McCulloch

R. Noack

T. SchulthessS. TodoS. TrebstShan"Ho Tsai

Invited speakers Hands$on tutorials

Documents

ALPS Montreal