1. Not Invented Here: The Re-use of Commercial Components in HEP Computing Jeremy Walton The Numerical Algorithms Group Ltd, UK

2. 2 Overview Changing priorities for HEP development –Build? Buy? Commercial supply of software – NAG - an introduction Commercial components in LHC++ –what and where Feedback from HEP –HEP/NAG synergy, technology transfer –Ongoing commercial development

3. 3 Development in LHC era Large Hadron Collider at CERN –Expected to enter production in 2005 –Data analysis will continue beyond 2020 –Total data volume ~ 100PB Evolution of CERNLIB –move from mainframe to distributed computing –move from Fortran to object-oriented language –Investigation of alternatives to internal development

4. 4 The LHC++ suite Tools for storing and analysing HEP data Provides CERNLIB functionality in C++ Re-uses existing work – where possible –e.g. CLHEP Uses standard solutions – where appropriate –e.g. OpenGL, STL, … Based on commercial components – where applicable

5. 5 Why not build? Reduced HEP development resources Support and maintenance issues –e.g. CERNLIB support continues to (~ 2003/6) Timescale considerations –Limited lifetime of developers –Long lifetime of LHC Make most appropriate use of resource –Only build what’s necessary –Build on components from elsewhere

6. 6 Numerical Algorithms Group Commercial scientific software company –Offices in Oxford, Munich, Chicago, Tokyo First numerical library developed in 1971 –> 1,000 routines, > 10,000 users worldwide Other products and services –statistics, visualisation, symbolics, simulation Collaborative development model –with experts, with customers Not-for-profit company (in UK)

7. 7 LHC++ commercial components LHC++ commercial components NAG C Library –collection of reliable and robust routines for linear algebra optimisation PDEs, ODEs FFTs Correlation, regression multivariate methods –Strong overlap with HEP requirements

8. 8 LHC++ commercial components LHC++ commercial components Open Inventor –Object-oriented 3D graphics library –Uses OpenGL for rendering –Defines standard 3D file format –Extensible IRIS Explorer –Modular visualisation toolkit –Strong support for distributed applications –Uses NAG C Library, Open Inventor, OpenGL

9. 9 Building on components HEPInventor –HEP presentation graphics library –Based on Open Inventor –Graphics requirements from PAW axes, histograms, page layout, printing HEP Explorer –HEP-specific IRIS Explorer modules –Focussed on interactive analysis histograms, Ntuple-like analysis, fitting

10. 10 HEP Explorer in LHC++ Event browser Histogram plotter Display

11. 11 Feedback from HEP to NAG MINOS error calculation required –being added to new NAG minimizers Support for CERNLIB special functions –being added to NAG C Library Better 1D (histogram) plotting –Now part of IRIS Explorer 4.0 Porting to Linux –IRIS Explorer 4.0 now available

12. 12 HEP/NAG synergy Better NAG support of HEP features –Frees HEP development and support resource –Improves coverage of NAG products elsewhere Ongoing process –Collaborative development model –Long-term relationship –Timescale considerations Important relationship for NAG