Timothy Williams

Papers and Articles

Huerta, E.A., Allen, G., Andreoni, I. et al. Enabling real-time multi-messenger astrophysics discoveries with deep learning, Nat Rev Phys 1, 600–608 (2019). https://doi.org/10.1038/s42254-019-0097-4
T. J. Williams, “Early Science on Theta,” in Computing in Science & Engineering, vol. 20, no. 3, pp. 73-77, May. 2018
W. Tang et al., Extreme Scale Plasma Turbulence Simulations on Top Supercomputers Worldwide, SC '16: Proceedings of the International Conference for High Performance Computing, Networking, Storage and Analysis, Salt Lake City, UT, 2016, pp. 502-513, doi: 10.1109/SC.2016.42.
T. J. Williams, "Delivering Science on Day One," in Computing in Science & Engineering, vol. 18, no. 2, pp. 104-107, Mar.-Apr. 2016.
B. Wang, S. Ethier, W. Tang, T. Williams, K. Ibrahim, K. Madduri, S. Williams, L. Oliker, "Kinetic Turbulence Simulations at Extreme Scale on Leadership-Class Systems," in Proceedings of SC13: International Conference for High Performance Computing, Networking, Storage and Analysis (SC '13). ACM, New York, NY, USA, , Article 82 , 12 pages. DOI=10.1145/2503210.2503258 https://doi.acm.org/10.1145/2503210.2503258.
S. Coghlan, K. Kumaran, R. M. Loy, P. Messina, V. Morozov, J. C. Osborn, S. Parker, K. M. Riley, N. A. Romero, and T. J. Williams. 2013. "Argonne applications for the IBM Blue Gene/Q, Mira." IBM J. Res. Dev. 57, 1 (January 2013), 140-150. DOI=10.1147/JRD.2013.2238371 https://dx.doi.org/10.1147/JRD.2013.2238371
Karmesin, J. Crotinger, J. Cummings, S. Haney, W. Humphrey, J. Reynders, S. Smith, T. Williams, "Array Design and Expression Evaluation in POOMA II," in Computing In Object-Oriented Parallel Environments, Lecture Notes in Computer Science 1505 (Springer, 1998).
S. F. Ashby, W. J. Bosl, R. D. Falgout, S. G. Smith, A. F. B. Tompson, T. J. Williams, "A Numerical Simulation of Groundwater Flow and Contaminant Transport on the Cray T3D and C90 Supercomputers," The International Journal of High Performance Computing Applications, Vol. 13, No. 1, 1999.
N. Mattor, T. J. Williams, D. W. Hewett, and A. M. Dimits, "The Delayed Coupling Method: An Algorithm for Solving Banded Diagonal Matrix Problems in Parallel," Proceedings of IMACS 97 conference (1997).
E. L. Altschuler, T. J. Williams, E. R. Ratner, R. Tipton, R. Stong, F. Dowla, and F. Wooten, "Possible Global Minimum Lattice Configurations for Thomson's Problem of Charges on a Sphere," Phys. Rev. Lett. 78, 2681 (1997).
A. M. Dimits, T. J. Williams, J. A. Byers, and B. I. Cohen, "Scalings of Ion-Temperature-Gradient-Driven Anomalous Transport in Tokamaks," Phys. Rev. Lett. 77, 71 (1996).
T. J. Williams and A. M. Dimits, "Gyrokinetic Simulation for Realistic Tokamak Parameters," NERSC Buffer, 19 No. 10, 1 (1995).
N. Mattor, T. J. Williams, and D. W. Hewett, "Algorithm for solving tridiagonal matrix problems in parallel ," Parallel Computing 21 1769 (1995).
A. M. Dimits, et al., "Gyrokinetic and Global Fluid Simulations of Tokamak Microturbulence and Transport," (Proc. of 16th Int. Conf. on Plasma Phys. and Cont. Fusion Res.) IAEA, Seville, Spain IAEA-CN-60/D-P-I-5, 1994.
E. L. Altschuler, T. J. Williams, E. R. Ratner, F. Dowla, and F. Wooten, "Method of Constrained Global Optimization," Phys. Rev. Lett. 72 2671 (1994).
B. I. Cohen, T. J. Williams, A. M. Dimits, and J. A. Byers, "Gyrokinetic simulations of E×B velocity-shear effects on ion-temperature-gradient modes,"Phys. Fluids B. 5, 2967 (1993).
T. J. Williams, "3D Gyrokinetic Particle-In-Cell Simulation of Fusion Plasma Microturbulence on Parallel Computers," Proc. 1993 SCS Simulation Multiconference High Performance Computing Symposium, Arlington, VA, March 29-April 1, 114-119.
B. I. Cohen and T. J. Williams, "Implementation of a Semi-Implicit Orbit-Averaged Gyrokinetic Particle Code," J. Comput. Phys. 107, 282 (1993).
T. J. Williams and Y. Matsuda, "3D Gyrokinetic Particle-In-Cell Codes On The TC2000 And CM2," In The 1992 MPCI Yearly Report: Harnessing the Killer Micros, E. R. Brooks et al. eds., UCRL-ID-107022-92, 303-311.
B. I. Cohen and T. J. Williams, "Semi-Implicit Particle Simulation of Kinetic Plasma Phenomena," J. Comput. Phys. 97, 224 (1991).
T. J. Williams, Y. Matsuda, and E. Boerner, "Parallel Particle Simulation On the TC2000 and CM-2,"In The 1991 MPCI Yearly Report: Attack of the Killer Micros, E. R. Brooks et al. eds., UCRL-ID-107022, 133-138.
L. L. LoDestro, et al., "Comparison of Simulations and Theory of Low-frequency Plasma Turbulence," (Proc. of 13th Int. Conf. on Plasma Phys. and Cont. Fusion Res.) IAEA, Washington D.C., IAEA-CN-53/D-1-3, 1990.
T. J. Williams, E. R. Tracy, and G. M. Vahala, "Decimation of a Turbulence Model Under Statistical Constraints," Phys. Rev. A 40, 3272 (1989).
T. J. Williams, E. R. Tracy, and G. M. Vahala, "Strong Decimation of the Betchov Model of Turbulence," Physica D 37, 200 (1989).
T. J. Williams, E. R. Tracy, and G. M. Vahala, "Application of Kraichnan's Decimated Amplitude Scheme to the Betchov Model of Turbulence," Phys. Rev. Lett., 49, 1922 (1987).

Contributed Conference Abstracts

Joseph A. Insley et al., "Secrets of the Dark Universe: Simulating the Sky on the Blue Gene/Q, The Outer Rim Simulation," visualization poster at SC13, Denver, CO, November 2013. (Additional author, as listed in extended abstract.)
Bei Wang et al., "Advances in Gyrokinetic Particle-in-Cell Simulation for Fusion Plasmas to Extreme Scale," research poster at SC12, Salt Lake City, UT, November 2012. (Author list too long, my name truncated.)
Jeff R. Hammond and Timothy J. Williams, "Blue Gene/Q Architecture, Programming Models, and Applications", SIAM Annual Meeting, July 2012.
Timothy Williams, "Characterizing Large-Scale Computational Physics," Bull. of the Amer. Phys. Soc., 56, No. 1, March 2011.
T. J. Williams, J. A. Crotinger, J. C. Cummings, "GTC++: An Object-Oriented, Parallel, Gyrokinetic PIC Simulation," 1998 meeting of APS Division of Plasma Physics (New Orleans, 16-20 Nov. 1998).
Timothy J. Williams, "Totally Tubular and Massively Parallel," 4th Annual Numerical Tokamak Symposium, Lake Tahoe, April 5-6, 1994.
Timothy J. Williams, Bruce I. Cohen, Andris M. Dimits, Jack. A. Byers, X. Xu, and John Stimson, "Advances in Gyrokinetic PIC Simulation," Proceedings of the The 15th International Conference on the Numerical Simulation of Plasmas, paper #3A9, Valley Forge, PA, September 7-9, 1994.
Timothy J. Williams and Andris M. Dimits, "Message-Passing Parallel Quasiballooning Gyrokinetic PIC Code," Bull. of the Amer. Phys. Soc., 39, 1726, November 1994.
Timothy J. Williams, "3D Message-Passing Gyrokinetic PIC Code," 3rd Annual Numerical Tokamak Symposium Dallas, March 16-17, 1994.
Timothy J. Williams, "A Generic Gyrokinetic PIC Simulation Code For Parallel Computers," International Sherwood Fusion Theory Conference, Dallas, March 14-16, 1994.
T. J. Williams, et. al., "Progress on Parallel Gyrokinetic PIC Simulation," Bull. of the Amer. Phys. Soc., 38, 2016, November 1993.
A. M. Dimits, et. al., "Toroidal Gyrokinetic Simulations with Ion-Ion Collisions," Bull. of the Amer. Phys. Soc., 38, 2015, November 1993.
J. A. Byers, et. al., "Convergence Studies on df Gyrokinetic Codes," Bull. of the Amer. Phys. Soc., 38, 2016, November 1993.
Timothy J. Williams, "3D Gyrokinetic Particle-in-cell Simulation on Parallel Computers," Proc. Supercomputing '92, Minneapolis, November 1993.
Timothy J. Williams, "3D Gyrokinetic PIC Simulation on High Performance Computers," Bull. of the Amer. Phys. Soc., 38, 1446, May 1993.
T. J. Williams, et. al., "Memory Access in Massively Parallel Gyrokinetic PIC Simulation," Bull. of the Amer. Phys. Soc., 37, 1557, November 1992.
A. M. Dimits, et. al., "Simulations of Plasma Turbulence using Quasiballooning Coordinates," Bull. of the Amer. Phys. Soc., 37, 1555, November 1992.
J. A. Byers, et. al., "3D Gyrokinetic Simulations of ITG Modes with Velocity Shear," Bull. of the Amer. Phys. Soc., 37, 1555, November 1992.
A. M. Dimits, et. al.,
"Generation and Effects of Sheared Perpendicular Flows in Plasmas with Nonzero dTperp/dr," Bull. of the Amer. Phys. Soc., 37, 1587, November 1992.
Andris M. Dimits, Timothy J. Williams, and J. A. Byers, "Nonlinear Particle and Fluid Simulations using Quasi-Ballooning Coordinates," International Sherwood Fusion Theory Conference, April 1992.
B. I. Cohen, et. al., , Timothy J. Williams, and J. A. Byers, "Gyrokinetic Simulations of Ion-Temperature-Gradient Modes with Sheared Poloidal Velocity," International Sherwood Fusion Theory Conference, April 1992.
B. I. Cohen, T. J. Williams, A. M. Dimits, and L. D. Pearlstein, "Gyrokinetic simulation of Velocity-Shear Effects on Ion-Temperature-Gradient Modes," Bull. of the Amer. Phys. Soc., 36, 2280, October 1991.
T J. Williams and Y. Matsuda, "Comparison Study: 3D Gyrokinetic PIC Codes on the Cray 2, TC2000, and CM2," Proceedings of the The 14th International Conference on the Numerical Simulation of Plasmas, paper #PT5, Annapolis, MD, September, 1991.
Timothy J. Williams, Bruce I. Cohen, Andris M. Dimits, and Lynda L. LoDestro, "Semi-Implicit Gyrokinetic Particle Simulation," International Sherwood Fusion Theory Conference, April 1991.
Y. Matsuda, T J. Williams, and J. Byers, "Three-Dimensional Gyrokinetic Particle Simulation of Ion Temperature Gradient Mode on Massively Parallel Computers," International Sherwood Fusion Theory Conference, April 1991.
L. L. LoDestro, B. I. Cohen, A. M. Dimits, and T. J. Williams, "Two-Dimensional Gyrokinetic Simulation Studies," International Sherwood Fusion Theory Conference, April 1991.
Y. Matsuda, B. I. Cohen, and T. J. Williams, “Improvements in the Gyrokinetic Simulation Method,” US-Japan Workshop on Advances in Simulation Techniques Applied to Plasmas and Fusion, Los Angeles, CA, September 1990.
Timothy J. Williams, Y. Matsuda, and E. Boerner, "Parallel Particle Simulation Algorithms on the CM-2 and BBN TC2000," Bull. of the Amer. Phys. Soc., 35:2001, November 1990.
B. I. Cohen, et. al., "Gyrokinetic Code Development," Bull. of the Amer. Phys. Soc., 35:2038, November 1990.
L. L. LoDestro, et. al., "Gyrokinetic Particle Simulation Studies," Bull. of the Amer. Phys. Soc., 35:2038, November 1990.
A. M. Dimits, B. I. Cohen, T. J. Williams, and W. W. Lee, "Comparison of Fluid and Gyrokinetic Simulations of the hi Instability," Bull. of the Amer. Phys. Soc., 35:2036, October 1990.
Timothy J. Williams, et. al., "Gyrokinetic Particle Simulations of Electrostatic Plasma Turbulence," International Sherwood Fusion Theory Conference, April 1990.
Bruce I. Cohen, Timothy J. Williams, "Semi-Implicit Particle Simulation of Kinetic Plasma Phenomena," International Sherwood Fusion Theory Conference, April 1990.
Timothy J. Williams, B. I. Cohen, and R. D. Sydora, "Optimizing Gyrokinetic Simulation Techniques," Bull. of the Amer. Phys. Soc., 34:2044, November 1989.
T J. Williams, G. Vahala, and E. Tracy, "Strong Decimation of the Betchov Model of Turbulence: Relation to DIA," Bull. of the Amer. Phys. Soc., 33:2020, October 1988.
T J. Williams, G. Vahala, and E. Tracy, "Results of Kraichnan's Decimated Amplitude Scheme for Model Turbulence," Bull. of the Amer. Phys. Soc., 32:1858, November 1987.
T. Williams, E. Tracy, and G. Vahala, "Decimation of Betchov's Model of Quadratic Turbulence: Comparison with the DIA," International Sherwood Fusion Theory Conference, April 1987.
E. Tracy, T. Williams, and G. Vahala, "A Test of Kraichnan's Decimation Scheme on Betchov's Model of Quadratic Turbulence," Bull. of the Amer. Phys. Soc., 31:1561, October 1986.
T. Williams, G. Vahala, and E. Tracy, "Decimation of a Modal Description of 2D Navier-Stokes Turbulence," Bull. of the Amer. Phys. Soc., 31:1561, October 1986.
Tim Williams, E. Tracy, and G. Vahala, "Decimation in Turbulence," International Sherwood Fusion Theory Conference, April 1986.
T. Williams and G. Vahala, "Nonlinear Dynamics and Point Models for Bumpy Tori," Bull. of the Amer. Phys. Soc., 29:1183, October 1984.

Presentations

"Aurora Early Science Program, CELS Computing Coffee Hour talk, Cotober 2019.
"Gyrokinetic PIC Simulation of Tokamak Edge Plasma, U. CPS Division Meeting Seminar, January 2020.
"Science on the Biggest Computers: The Next Generation, U. Chicago Research Computing Center Seminar, June 2016.
"Joint ASCR Facilities Application Readiness and Performance Portability," briefiing to DOE Advanced Scientific Computing Advisory Committee (ASCAC), November 2014.
"Overview of the ALCF Early Science Program," Early Science Program Investigators Meeting, ANL, 15 May 2013. [Similar: "Overview of the ALCF Early Science Program," MiraCon 2013 (ESP Community Meeting), ANL, 4 March 2013]
"Allocation Programs at the ALCF," at ALCF Winter Workshop, ANL, October 2012.
"INCITE and HPC on BG/P and BG/Q at ALCF," invited talk at HSCCI Health Sciences Research Summit: Application of HPC to Health Sciences, Rochester, NY 29 June 2012.
"Workshop Intro," ESP April Workshop - "Code for Q," 30 April 2012.
"Workshop Intro," ESP March Workshop - "Code for Q," 19 March 2012.
“Preparing Applications for Mira, a 10-petaFLOPS IBM Blue Gene/Q System,” Argonne National Lab booth talk at SC11, 16 November 2011.
"Closing Remarks: Science," at ALCF Getting Started Workshop, ANL, 4 October 2011.
"Preparing Applications for Mira, a 10 PFLOPS IBM Blue Gene/Q Machine," talk at 2011 Fall Creek Falls Conference, Gatlinburg, TN, 15 September 2011.
“Overview of the Argonne Leadership Computing Facility,” presented at CScADS Summer 2011 Workshop I, 18 July 2011.
"Characterizing Large-Scale Computational Physics," talk H24 8, APS March Meeting, Dallas, 22 March 2011 (Bull. of the Amer. Phys. Soc., 56, No. 1, March 2011).
"Distributed Calculations on Fixed-Income Securities," Keynote at 2nd Workshop on High Performance Computational Finance, Portland, OR, November 2009.
"Compile-Time Polymorphism in C++: Performance, Generics, and Extensibility," IBM T. J. Watson seminar presented on 9 February 2000.
“Pooma 2.1,” ACL Seminar presented on 28 September 1999.
"Using POOMA Particles Classes," Presented by Tim Williams at Tecolote class at LANL, 25 August 1998.
John V. W. Reynders and Timothy J. Williams, "Pooma: Parallel Object-Oriented Methods and Applications," Slides presented at DOE 2000 Workshop, Washington DC, March 6-7 1996.
"POOMA: Focus on POOMA Applications," Invited talk presented at 1996 Cray User Group Meeting, Barcelona.
Lectures presented at NERSC Massively Parallel Processing Workshop, June 14-30, 1995.:

Scientific Computing: Where Does MPP Fit In?
Parallel Programming Paradigms
Thinking Parallel
High-Level Approaches I: Object-Oriented Methods
Gyrokinetic PIC Simulation on Massively Parallel Processors
Lab instruction: Timing MPP Codes
Lab instruction: Exercises for NERSC MPP Workshop, and Solutions.

Publications

Books

Book Chapters

Papers and Articles

Invited Conference Papers

Contributed Conference Papers

Invited Conference Abstracts

Contributed Conference Abstracts

Technical Reports

Presentations