1. Cooperative International Simulations with McStas Vickie Lynch, Meili Chen, John Cobb, Mark Hagen, James Kohl, Stephen Miller, Michael Reuter, Sudharshan Vazhkudai Oak Ridge National Laboratory Kim Lefmann, Peter Willendrup Riso National Laboratory in Denmark Emmanuel Farhi Institut Laue Langevin in France

2. McStas collaboration McStas is a neutron ray-trace simulation package that simulates neutron scattering instruments. Mutual benefits of McStas collaboration –Access to distributed computing resources on the TeraGrid –Improved performance with MPI parallel implementation –Standardized NeXus output –Improved visualization with Neutron Science portal viewer

3. TeraGrid Community Account Data to portal Visualize from portal Data to portal Run on TeraGrid Choose resource

4. Simulation portal development: Input A McStas simulation is available at the Neutron Science portal for simulating backscattering experiments Simulation tab has been added to portal Java panel added for input –Pull-down menu for choosing TeraGrid resource –JSpinner with min, max, and step for input parameters –Text field for input source file

5. Simulation portal development: Access Have community certificate and TeraGrid community account A community certificate will be used to access TeraGrid resources. –Login portal with XCAM/UCAM username and password –Have permanent log to identify each job with XCAM/UCAM username –Output in TeraGrid community account must be in unique directory so jobs do not overwrite jobs of other users A shared directory is available for output from the simulation portal –Just like approved proposal shared directories –Community account users can share output

6. Community certificate and accounts Distinguished Name: /DC=org/DC=doegrids/OU=People/CN=John Cobb NSTG Jimmy Neutron 91500 ResourceUsername IU login.bigred.iu.teragrid.orgtg-jneutron NCSA login-co.ncsa.teragrid.orgjneutron login-cu.ncsa.teragrid.orgjneutron tg-login.ncsa.teragrid.orgjneutron login-w.ncsa.teragrid.orgjneutron ORNL tg-login.ornl.teragrid.orgjneutron Purdue tg-login.purdue.teragrid.orgjneutron TACC tg-login.lonestar.tacc.teragrid.org tg458668 tg-viz-login.tacc.teragrid.orgtg458668 UC/ANL tg-login.uc.teragrid.orgjneutron

7. Simulation portal development: TeraGrid GLOBUS used to send jobs to TeraGrid –Installed on local machine. –Long term proxy initialized with grid-proxy-init. –Jobs submitted with globus-job-submit. –Jobs are monitored with globus-job-status using URL returned from globus-job-submit until “DONE” returns. –Output returned using globus-url-copy. SSH key to another local machine from portal to run globus. TeraGrid machines have files already available –Compiled executables –Source input files –Batch script A network weather service available in the TeraGrid portal has recent statistics of how long it took batch jobs to complete and can be used to choose the fastest machine to run the jobnetwork weather service

8. Simulation portal development: Output A NeXus file is created on TeraGrid machine –Simulation portal returns NeXus histogram file Output of simulation is NeXus file which is able to be viewed by the same 2-D viewer used to display experimental results

9. Simulation Portal Future Work Gateway needs community proxy for users Show status of job on portal input screen More simulations in portal Data analysis of NeXus files in portal –fitting

10. Future Goals of McStas Collaboration More McStas instrument simulations in portal Improved visualization Improved performance More sample kernels Event mode and histogram interfaces An analysis interface

11. Simulation portal development: DEMO Neutron Science approach: Neutron Science User Portal Neutron Science User Portal