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Fast data fitting services on TeraGrid for SNS data analysis Meili Chen, John Cobb,

Fast data fitting services on TeraGrid for SNS data analysis Meili Chen, John Cobb, Mark Hagen, Vickie Lynch, Steve Miller Introduction

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Fast data fitting services on TeraGrid for SNS data analysis Meili Chen, John Cobb,

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  1. Fast data fitting services on TeraGrid for SNS data analysis Meili Chen, John Cobb, Mark Hagen, Vickie Lynch, Steve Miller Introduction The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) produces the most intense pulsed neutron beams in the world, which makes it an excellent facility for conducting neutron scattering research. The SNS can support up to 24 neutron instruments on 18 beam lines. Fast analysis of the data obtained from SNS instruments is critical for quick data comparison to resolution-convolved models and for making automated on-the-fly experimental adjustment/control possible. Collaborating with SNS instrument scientists, the Neutron Science TeraGrid Gateway (NSTG) team at ORNL has been designing and developing software tools, which use parallel computing techniques to perform fast data fitting on the TeraGrid resources. A data analysis GUI interface integrated with SNS portal is also under development for easy user access.

  2. 60 m Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) 2 - Backscattering Spectrometer 1B - Disordered Mat’ls Diffractometer 18 - Wide Angle Chopper Spectrometer Bird’s eye view of SNS 17 - High Resolution Chopper Spectrometer PROTONS 3 - High Pressure Diffractometer 14B - Hybrid Spectrometer 15 – Spin Echo 4A - Magnetism Reflectometer 4B - Liquids Reflectometer 13 - Fundamental Physics Beamline 12 - Single Crystal Diffractometer 5 - Cold Neutron Chopper Spectrometer 6 – Small Angle Scatt. Diffractometer 11A - Powder Diffractometer 9 - Engineering Diffractometer SNS can support up to 24 neutron instruments on 18beam lines SNS Univ. SING Canada • Spallation neutron source at ORNL, Tennessee, USA • A $1.4 billion project of the US Department of Energy (DOE) • Partnership of DOE labs – Argonne, Berkeley, Brookhaven, Jefferson, Los Alamos, Oak Ridge • Font Color: • Instrument in the user program • Future instrument

  3. SNS NCCS HFIR Neutron Science TeraGrid Gateway (NSTG) Along with its sister facility, the High Flux Isotope Reactor, SNS makes Oak Ridge a mecca for neutron-scattering research and therefore an excellent location for introducing the Neutron Science community to the world class computing resources of TeraGrid. SNS instruments Neutron Science TeraGrid Gateway (NSTG) at ORNL, one of the TG resource providers, is funded by National Science Foundation and primarily concentrates on SNS applications. High Flux Isotope Reactor – HFIR

  4. FitSrv_nl2 is ready to hook up to customized fitting functions Parameter fitting tool -1: FitSrv_nl2 • FitSrv_nl2 is a software tool developed by NSTG team. It employs NL2SOL algorithm to perform parallel parameter fitting on the TeraGrid resources. • The NL2SOL, an adaptive nonlinear least-squares algorithm, was selected because of its robustness to nonlinear function and nonzero residuals. • NL2SOL/NL2SNO software package*, developed by J. E. Dennis. JR, D. M. Gay, and R. E. Welsch, is integrated with FtiSrv_nl2. • By means of MPI-F90, FitSrv_nl2 parallelizes NL2SOL and NL2SNO optimization processes and performs fast parameter fitting. • Two customized routines for each instrumentare required for experimental data input and specific fitting functions. • User can employ the SNS data analysis portal to run FitSrv_nl2 on TeraGrid without having to know NL2SOL/NL2SNO, computing grids, or parallel computing once the above routines are provided. *NL2SOL – An Adaptive Nonlinear Least-Squares Algorithm, ACM Trans. Math. Softw. 7,3 (Sept.1981), 369-383

  5. Parameter fitting tool - 2: FitSrv_dakota • FitSrv_dakota will make the software package DAKOTA available for user to perform parallel data analysis on TeraGrid resources via the SNS data analysis portal*1. • DAKOTA*2 (Design Analysis Kit for Optimization and Terascale Applications) package, developed by Sandia National Laboratories, contains algorithms for optimization with gradient- and nongradient-based methods; parameter estimation with nonlinear least squares methods; uncertainty qualification; and sensitivity/variance analysis. • The initial FitSrv_dakota effort focuses on DAKOTA optimization tools.The following optimization packages are integrated with DAKOTA: • COLINY (Common Optimization Library Interface +) • CONMIN (CONstrained MINimization) • JEGA (SOGA & MOGA: single- and multi-objective genetic algorithms) • OPT++ (A variety of Newton-based methods +) • PICO (Parallel Integer Combinatorial Optimization) • Also Commercial packages DOT, MOOCHO, NLPQLP, and NPSOL. • By means of FitSrv_dakota and SNS portal, users will be able to perform fast generalized parameter fitting on TeraGrid without having to know parallel computing, computing grids, DAKOTA features, or its scripting language. FitSrv_dakota will be available through SNS portal and become an user-friendly data analysis tool ! URLS:: *1. SNS portal: http://neutronsr.us; *2. DAKOTA:http://www.cs.sandia.gov/DAKOTA

  6. SNS Data Analysis Portal - Fitting tool usage and FitSrv_nl2 scalability * - Experimental data from instrument or data file to SNS portal 1. Data to portal 3. Visualize from portal 2. Choose fitting method Run on TeraGrid 3. Fitting result from portal Result to portal Scaling of FitSrv_nl2 on Mercury at NCSA TeraGrid Community Account • Users at portal choose fitting method and related parameters • Input sent to TeraGrid on community account for data fitting • Fitting results sent back to portal for visualization or performance study *The fitting service is not currently enabled in the production neutron portal. It will be enabled on an instrument by instrument basis for each objective function definition. (“Black box”)

  7. Reservations: The parallel data fitting service will be integrated into the production portal and into the routine experimental workflow. This implies that the cyber resources need to be available during scheduled experimental periods. TeraGrid resource reservations are a pre-requisite to incorporating real-time parallel fitting into experimental data acquisition and analysis. This enables SNS to leverage its science investment by utilizing national scale cyberinfrastructure in real-time • Facility based allocations (Gateway): Beam-line operators need the ability to provide cyberinfrastructure for users What we need from TeraGrid ?

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