NERSCPowering Scientific Discovery for 50 Years

Zhengji Zhao

Zhengji-Zhao.jpg
Zhengji Zhao , Ph.D.
Phone: (510) 631-5025
Fax: (510) 486-6459
1 Cyclotron Road
Mailstop: 59R4010A
Berkeley, CA 94720 us

Biographical Sketch

Zhengji Zhao is an HPC Architecture and Performance Engineer at NERSC's Advanced Technologies Group (ATG). Before joining ATG, she was an HPC consultant at NERSC (2007 - 2022). She has board experience in HPC, including supporting materials science and chemistry applications, participating in system procurements, developing workload analysis tools, and porting applications to many core and GPU systems using parallel programming models such as MPI, OpenMP, OpenACC, and CUDA Fortran. In recent years, she worked on bringing transparent checkpointing capabilities to NERSC’s production workloads, developing checkpoint/restart standards for HPC production workloads. Her current research is focused on power analysis and benchmarking for NERSC future system procurements.

Her publications include the work of developing the reduced density matrix (RDM) method for electronic structure calculations, a highly accurate alternative to the wavefunction-based computational chemistry methods, the award-winning development work of the linear scaling 3D fragment (LS3DF) method for large-scale electronic structure calculations (the best poster award in SC07, and the ACM Gordon Bell prize for Algorithm Innovation in SC08). In addition, she has served on the program committee for several HPC conference series, such as SC, CUG, WACCPD, IXPUG, and Future Computing, and as the lead organizer for the workshop series on checkpointing (e.g., SuperCheck-SC22). She received her Ph.D. in computational physics and an M.S. in computer science from New York University, NY, USA; an M.S. in theoretical physics from Peking University, Beijing, China; and a B.S. in theoretical physics from Jilin University, Changchun, China.

Before coming to the US, she was a faculty at Peking University, teaching classical and modern physics to physics and chemistry major undergraduates (1991 - 1996).

Honors and Awards

  • WACCPD19 Best Paper Award (with Hongzhang Shan, and Marcus Wagner)
  • SC08 ACM Gordon Bell Prize for Algorithm Innovation (with Lin-Wang Wang, Byounghak Lee, Hongzhang Shan, Juan Meza, Erich Strohmaier, and David Bailey)
  • SC07 Best Poster Award (with Lin-Wang Wang and Juan Meza)

Journal Articles

Florian Wende, Martijn Marsman, Jeongnim Kim, Fedor Vasilev, Zhengji Zhao, Thomas Steinke, "OpenMP in VASP: Threading and SIMD", International Journal of Quantum Chemistry, December 19, 2018,

Yun (Helen) He, Brandon Cook, Jack Deslippe, Brian Friesen, Richard Gerber, Rebecca Hartman­-Baker, Alice Koniges, Thorsten Kurth, Stephen Leak, Woo­Sun Yang, Zhengji Zhao, Eddie Baron, Peter Hauschildt, "Preparing NERSC users for Cori, a Cray XC40 system with Intel Many Integrated Cores", Concurrency and Computation: Practice and Experience, August 2017, 30, doi: 10.1002/cpe.4291

The newest NERSC supercomputer Cori is a Cray XC40 system consisting of 2,388 Intel Xeon Haswell nodes and 9,688 Intel Xeon‐Phi “Knights Landing” (KNL) nodes. Compared to the Xeon‐based clusters NERSC users are familiar with, optimal performance on Cori requires consideration of KNL mode settings; process, thread, and memory affinity; fine‐grain parallelization; vectorization; and use of the high‐bandwidth MCDRAM memory. This paper describes our efforts preparing NERSC users for KNL through the NERSC Exascale Science Application Program, Web documentation, and user training. We discuss how we configured the Cori system for usability and productivity, addressing programming concerns, batch system configurations, and default KNL cluster and memory modes. System usage data, job completion analysis, programming and running jobs issues, and a few successful user stories on KNL are presented.

Zhengji Zhao, Juan Meza, Byounghak Lee, Hongzhang Shan, Erich Strohmaier, David Bailey, "Linearly Scaling 3D Fragment Method for Large-Scale Electronic Structure Calculations", 2009 J. Phys.: Conf. Ser. 180 012079, July 1, 2009,

Zhengji Zhao, Lin-Wang Wang, and Juan Meza, "A divide and conquer linear scaling three dimensional fragment method for large scale electronic structure calculations", J. Phys.: Condens. Matter 20 (2008) 294203., June 24, 2008,

Maho Nakata, Bastiaan J. Braams, Katsuki Fujisawa, Mituhiro Fukuda, Jerome K. Percus, Makoto Yamashita, and Zhengji Zhao, "Variational calculation of second-order reduced density matrices by strong N-representability conditions and an accurate semidefinite programming solver", J. Chem. Phys., 128, 1, (2008), April 29, 2008,

Lin-Wang Wang, Zhengji Zhao, and Juan Meza, "Linear-scaling three-dimensional fragment method for large-scale electronic structure calculations", Phys. Rev. B 77, 165113 (2008), April 10, 2008,

M.Fukuda, B.J.B.Braams, M.Nakata, M.L.Overton, J.K.Percus, M.Yamashita, and Z. Zhao, "Large-scale semi-definite programs in electronic structure calculations", Mathematical Programming, series B 109, 553-580, Springer Berlin / Heidelberg, (2006)., January 1, 2007,

M. Nakata, B. J. Braams, M. Fukuda, J. K. Percus, M. Yamashita, and Z. Zhao, "Simple Hamiltonians which exhibit drastic failures by variational determination of the 2-RDM with some well known N-representability conditions", J. Chem. Phys., 125, 244109 (2006), December 27, 2006,

Zhengji Zhao , Lin-Wang Wang, and Fengmin Wu, "Wavefunction localizations in bulged CdSe nanowires", J. of Comp. and Theo. Nano., pp.247-251, vol.4, no. 2, (2007)., July 2, 2006,

Zhengji Zhao , Juan Meza, and Michel Van Hove, "Using Pattern Search Methods for Surface Structure Determination", J. Phys.: Condens. Matter 18, 8693-8706 (2006), June 9, 2006,

Zhao, Zhengji, Wang, Lin-Wang and Meza, Juan, "Motif based Hessian matrix for ab initio geometry optimization of nanostructures", Phys. Rev. B 73, 193309 (2006), May 17, 2006,

Zhengji Zhao , Bastiaan J. Braams, Mituhiro Fukuda, Michael L. Overton and Jerome K. Percus, "The Reduced Density Matrix Method for Electronic Structure Calculations and the Role of Three-Index Representability Conditions", J. Chem. Phys. 120, 2095 (2004), February 1, 2004,

Conference Papers

Anish Govind, Sridutt Bhalachandra, Zhengji Zhao, Ermal Rrapaj, Brian Austin, and Hai Ah Nam, "Comparing Power Signatures of HPC Workloads: Machine Learning vs Simulation", In Proceedings of the SC '23 Workshops of The International Conference on High Performance Computing, Network, Storage, and Analysis (SC-W '23)., New York, NY, USA, Association for Computing Machinery, November 2023, 1890-1893, doi: 10.1145/3624062.3624274

Zhengji Zhao, Ermal Rrapaj, Sridutt Bhalachandra, Brian Austin, Hai Ah Nam, Nicholas Wright, "Power Analysis of NERSC Production Workloads", In Proceedings of the SC '23 Workshops of The International Conference on High Performance Computing, Network, Storage, and Analysis (SC-W '23), New York, NY, USA, Association for Computing Machinery, November 2023, 1279-1287, doi: 10.1145/3624062.3624200

Zhengji Zhao, Brian Austin, Stefan Maintz, Martijn Marsman, "VASP Performance on Cray EX Based on NVIDIA A100 GPUs and AMD Milan CPUs", Cray User Group 2023, Helsinki, Finland, May 11, 2023,

Gene Cooperman, Dahong Li, Zhengji Zhao, "Debugging MPI Implementations via Reduction-to-Primitives", Third International Symposium on Checkpointing for Supercomputing (SuperCheck-SC22), held in conjunction with SC22, To be published with IEEE CPS, November 14, 2022,

Testing correctness of either a new MPI implementation or a transparent checkpointing package for MPI is inherently difficult. A bug is often observed when running a correctly written MPI application, and it produces an error. Tracing the bug to a particular subsystem of the MPI package is difficult due to issues of complex parallelism, race conditions, etc. This work provides tools to decide if the bug is: in the subsystem implementing of collective communication; or in the subsystem implementing point-to-point communication; or in some other subsystem. The tools were produced in the context of testing a new system, MANA. MANA is not a standalone MPI implementation, but rather a package for transparent checkpointing of MPI applications. In addition, a short survey of other debugging tools for MPI is presented. The strategy of transforming the execution for purposes of diagnosing a bug appears to be distinct from most existing debugging approaches.

Yao Xu, Zhengji Zhao, Rohan Garg, Harsh Khetawat, Rebecca Hartman-Baker, Gene Cooperman, "MANA-2.0: A Future-Proof Design forTransparent Checkpointing of MPI at Scale", Second International Symposium on Checkpointing for Supercomputing, held in conjunction with SC21. Conference website: https://supercheck.lbl.gov/, November 15, 2021,

Doru Thom Popovici, Andrew Canning, Zhengji Zhao, Lin-Wang Wang, John Shalf, "A Systematic Approach to Improving Data Locality Across Fourier Transforms and Linear Algebra Operations", International Conference on Supercomputing 2021 (ICS-2021) (Online), https://ics21.github.io/, June 14, 2021,

Benjamin Driscoll, and Zhengji Zhao, "Automation of NERSC Application Usage Report", Seventh Annual Workshop on HPC User Support Tools (HUST 2020), held in conjunction with SC20, Online, November 11, 2020,

Hongzhang Shan, Zhengji Zhao, and Marcus Wagner, "Accelerating the Performance of Modal Aerosol Module of E3SM Using OpenACC", (won the best paper award), Sixth Workshop on Accelerator Programming Using Directives (WACCPD) in SC19, November 18, 2019,

Tianmu Xin, ​Zhengji Zhao​, Yue Hao, Binping Xiao, Qiong Wu, Alexander Zaltsman, Kevin Smith, and Xinmin Tian, "Performance Tuning to close Ninja Gap for Accelerator Physics Emulation System (APES) on Intel Xeon Phi Processors", Proceeding of the 14th ​International Workshop on OpenMP (​IWOMP18​), Barcelona Spain, September 26, 2018,

Tuomas Koskela, Zakhar Matveev, Charlene Yang, Adetokunbo Adedoyin, Roman Belenov, Philippe Thierry, Zhengji Zhao, Rahulkumar Gayatri, Hongzhang Shan, Leonid Oliker, Jack Deslippe, Ron Green, Samuel Williams, "​A Novel Multi-Level Integrated Roofline Model Approach for Performance Characterization", International Conferences on High Performance Computing 2018, June 24, 2018,

Thorsten Kurth, William Arndt, Taylor Barnes, Brandon Cook, Jack Deslippe, Doug Doerfler, Brian Friesen, Yun (Helen) He, Tuomas Koskela, Mathieu Lobet, Tareq Malas, Leonid Oliker, Andrey Ovsyannikov, Samual Williams, Woo-Sun Yang, Zhengji Zhao, "Analyzing Performance of Selected NESAP Applications on the Cori HPC System", High Performance Computing. ISC High Performance 2017. Lecture Notes in Computer Science, Volume 10524, June 22, 2017,

Yun (Helen) He, Brandon Cook, Jack Deslippe, Brian Friesen, Richard Gerber, Rebecca Hartman­-Baker, Alice Koniges, Thorsten Kurth, Stephen Leak, Woo­Sun Yang, Zhengji Zhao, Eddie Baron, Peter Hauschildt, "Preparing NERSC users for Cori, a Cray XC40 system with Intel Many Integrated Cores", Cray User Group 2017, Redmond, WA. Best Paper First Runner-Up., May 12, 2017,

Florian Wende, Martijn Marsman, Zhengji Zhao, Jeongnim Kim, "Porting VASP from MPI to MPI+ OpenMP [SIMD]-Optimization Strategies, Insights and Feature Proposals", 13th International Workshop on OpenMP (IWOMP), September 20–22, 2017, Stony Brook, NY, USA, February 18, 2017,

Hongzhang Shan, Samuel Williams, Yili Zheng, Weiqun Zhang, Bei Wang, Stephane Ethier, Zhengji Zhao, "Experiences of Applying One-Sided Communication to Nearest-Neighbor Communication", http://conferences.computer.org/paw/2016/, Salt Lake City, Utah, November 14, 2016,

Zhengji Zhao, and Martijn Marsman, "Estimating the Performance Impact of the MCDRAM on KNL Using Dual-Socket Ivy Bridge nodes on Cray XC30", https://cug.org/, London, UK, May 11, 2016,

Zhengji Zhao, Doug Petesch, David Knaak, and Tina Declerck, "I/O Performance on Cray XC30", Cray User Group Meeting, May 4, 2014,

Zhengji Zhao, Katie Antypas, Nicholas J Wright, "Effects of Hyper-Threading on the NERSC workload on Edison", 2013 Cray User Group Meeting, May 9, 2013,

Jack Deslippe, Zhengji Zhao, "Comparing Compiler and Library Performance in Material Science Applications on Edison", Paper. Proceedings of the Cray User Group 2013, 2013,

Megan Bowling, Zhengji Zhao and Jack Deslippe, "The Effects of Compiler Optimizations on Materials Science and Chemistry Applications at NERSC", A paper presented in the Cray User Group meeting, Apri 29-May-3, 2012, Stuttgart, German., May 3, 2012,

Zhengji Zhao, Mike Davis, Katie Antypas, Yushu Yao, Rei Lee and Tina Butler, "Shared Library Performance on Hopper", A paper presented in the Cray User Group meeting, Apri 29-May-3, 2012, Stuttgart, German., May 3, 2012,

Zhengji Zhao, Yun (Helen) He and Katie Antypas, "Cray Cluster Compatibility Mode on Hopper", A paper presented in the Cray User Group meeting, Apri 29-May-3, 2012, Stuttgart, Germany., May 1, 2012,

Zhengji Zhao and Nick Wright, "Performance of Density Functional Theory codes on Cray XE6", A paper presented in the Cray User Group meeting, May 23-26, 2011, Fairbanks, Alaska., May 24, 2011,

Zhengji Zhao, and Lin-Wang Wang, "The application of the LS3DF method to CdSe/CdS core/shell structures", A paper presented in the Cray User Group meeting, May 4-7, 2009, Atlanta, GA, May 4, 2009,

Lin-Wang Wang, Byounghak Lee, Hongzhang Shan, Zhengji Zhao, Juan Meza, Erich Strohmaier, David Bailey,, "Linearly Scaling 3D Fragment Method for Large-Scale Electronic Structure Calculations", An award winning paper (ACM Gordon Bell Prize for algorithm innovation in SC08), Proceedings of the 2008 ACM/IEEE conference on Supercomputing, Article No. 65 (2008)., November 20, 2008,

Book Chapters

David H. Bailey, Lin-Wang Wang, Hongzhang Shan, Zhengji Zhao, Juan Meza, Erich Strohmaier, and Byounghak Lee, "Tuning an Electronic Structure Code", a book chapter in Performance Tuning of Scientific Applications, edited by David H. Bailey, Robert F. Lucas, Samuel W. Williams (2010)., ( November 23, 2010)

Bastiaan Braams, Jerry Percus and Zhengji Zhao, "The T1 and T2 representability conditions", Reduced-Density-Matrix Mechanics -- with applications to many-electron atoms and molecules, A book edited by David Mazziotti, John Wiley Advances in Chemical Physics Series (2007)., ( March 27, 2007)

Presentation/Talks

Zhengji Zhao, Brian Austin, Stefan Maintz, Martijn Marsman, VASP Performance on Cray EX Based on NVIDIA A100 GPUs and AMD Milan CPUs, Cray User Group 2023, Helsinki, Finland, May 11, 2023,

Zhengji Zhao and Rebecca Hartman-Baker, Checkpoint/Restart Project Update, Internal report, November 29, 2022,

Zhengji Zhao, Introduction to the CRI standard 1.0, A BOF presentation in the International Conference for High Performance Computing, Networking, Storage and Analysis (SC22), November 15, 2022,

Robin Shao, Thorsten Kurth, Zhengji Zhao, NERSC Job Script Generator, HUST-22: 9th International Workshop on HPC User Support Tools, November 14, 2022,

NERSC is the primary scientific computing facility for DOE’s Office of Science. NERSC supports diverse production workloads across a wide range of scientific disciplines, which requires a rather complicated queue structure with various resource limits and priorities. It has been challenging for users to generate proper job scripts to optimally use the systems. We developed a Slurm job script generator, a web application to help users not only generate job scripts but also learn how the batch system works. The job script generator was first deployed in 2016 to help generate an optimal process/threads affinity for the hybrid MPI + OpenMP applications for NERSC’s Cori system, and was recently extended to support more systems and use cases. In this talk, we will present the features supported in our job script generator, and describe the code design and implementation, which is easily adaptable to other centers who deploy Slurm.

Zhengji Zhao, Welcome to SuperCheck-SC22, Opening/Closing Remarks in the third International Symposium on Checkpointing for Supercomputing (SuperCheck-SC22), held in conjunction with SC22, November 14, 2022,

Tarun Malviya, Zhengji Zhao, Rebecca Hartman-Baker, Gene Cooperman, Extending MPI API Support in MANA, A lightning talk presented in SuperCheck-SC22 held in conjunction with SC22, November 14, 2022,

Zhengji Zhao, Running VASP on Perlmutter, A presentation in the VASP Hands-on user training (Online), September 27, 2022,

Zhengji Zhao, Requirements Report on the Checkpoint/Restart Interface Standard, NERSC Lunchtime Talk, August 22, 2022,

Rebecca Hartman-Baker, Zhengji Zhao, Checkpoint/Restart Project Update, CR Collaboration Day, August 9, 2022,

Zhengji Zhao, Welcome to C/R Requirements Gathering Workshop, Opening/Closing Remarks in the Checkpoint/Restart Requirements Gathering Workshop (Online), July 12, 2022,

Yao Xu, Zhengji Zhao, Rohan Garg, Harsh Khetawat, Rebecca Hartman-Baker, and Gene Cooperman, MANA-2.0: A Future-Proof Design for Transparent Checkpointing of MPI at Scale, November 15, 2021,

Zhengji Zhao, Welcome to SuperCheck-SC21, Opening/Closing Remarks in the Second International Symposium on Checkpointing for Supercomputing (SuperCheck-SC21) held in conjunction with the International Conference for High Performance Computing, Networking, Storage and Analysis (SC21), November 15, 2021,

Zhengji Zhao, A Preliminary Report on MANA Status on Cori, MANA Collaboration Kick-off Meeting, October 26, 2021,

Zhengji Zhao, Rebecca Hartman-Baker, Checkpoint/Restart (C/R) Vision at NERSC, C/R project update meeting (internal), August 13, 2021,

Doru Thom Popovici, Andrew Canning, Zhengji Zhao, Lin-Wang Wang, John Shalf, Data Layouts are Important, ARRAY 2021 (Online), June 21, 2021,

Zhengji Zhao, Rebecca Hartman-Baker, Our Vision and Strategies to Checkpoint/Restart Production Workloads at NERSC, NERSC Resilience Workshop (Online), June 17, 2021,

Zhengji Zhao, Checkpoint/Restart VASP Jobs Using MANA on Cori, NERSC User Training (Online), May 25, 2021,

Zhengji Zhao, Checkpoint/Restart MPI Applications with MANA on Cori, NERSC User Training (Online), May 7, 2021,

Zhengji Zhao, and Rebecca Hartman-Baker, Checkpoint/Restart Deployment at NERSC, PEAD-SIG Meeting at Cray User Group Meeting 2021 (Online), May 6, 2021,

Prashant Singh Chouhan, Harsh Khetawat, Neil Resnik, Jain Twinkle, Rohan Garg, Gene Cooperman, Rebecca Hartman-Baker and Zhengji Zhao, Improving scalability and reliability of MPI-agnostic transparent checkpointing for production workloads at NERSC, First International Symposium on Checkpointing for Supercomputing. Conference website: https://supercheck.lbl.gov/archive/supercheck21, February 4, 2021,

Zhengji Zhao, Rebecca Hartman-Baker, and Gene Cooperman, Deploying Checkpoint/Restart for ProductionWorkloads at NERSC, A presentation at SC20 State of the Practice Talks, November 17, 2020,

Zhengji Zhao, Checkpoint/Restart Options on Cori, NERSC User Group Monthly Webinar, September 24, 2020,

Zhengji Zhao, Programming Environment and Compilation, NERSC New User Training, Berkeley, CA, June 16, 2020,

Zhengji Zhao, and Rebecca Hartman-Baker, Proposal to increase the flex queue priority, NERSC Queue Committee Meeting, Berkeley, CA, June 1, 2020,

Zhengji Zhao, Running Variable-Time Jobs on Cori, Hans-on User training on Variable-Time Jobs, Berkeley, CA, May 21, 2020,

Zhengji Zhao, Rebecca Hartman-Baker, Checkpoint/Restart (C/R) Project Plan, Small P Project Meeting, Berkeley CA, May 15, 2020,

Zhengji Zhao, and Jessica Nettleblad, NERSC Dotfile Migration to /etc/profile.d, Consulting Team Meeting, Berkeley CA, February 18, 2020,

Zhengji Zhao, Automation of NERSC Application Usage Report, Application Usage Page Support Transition Meeting, Berkeley CA, December 4, 2019,

Hongzhang Shan, Zhengji Zhao, and Marcus Wagner, Accelerating the Performance of Modal AerosolModule of E3SM Using OpenACC, Sixth Workshop on Accelerator Programming Using Directives (WACCPD) in SC19, November 18, 2019,

Zhengji Zhao, Checkpointing and Restarting Jobs with DMTCP, NERSC User Training on Checkpointing and Restarting Jobs Using DMTCP, November 6, 2019,

Lixin Ge, Chou Ng, Zhengji Zhao, Jeff Hammond, and Karen Zhou, OpenMP Hackathon Acrum ACE3P, NERSC Application Readiness Meeting, October 30, 2019,

Zhengji Zhao, Programming Environment and Compilation, NERSC New User Training, June 21, 2019,

Zhengji Zhao, Running VASP on Cori KNL, VASP User Hands-on KNL Training, June 18, 2019, Berkeley CA, June 18, 2019,

Thorsten Kurth, Joshua Romero, Everett Phillips, and Massimiliano Fatica, Brandon Cook, Rahul Gayatri, Zhengji Zhao, and Jack Deslippe, Porting Quantum ESPRESSO Hybrid Functional DFT to GPUs Using CUDA Fortran, Cray User Group Meeting, Montreal, Canada, May 5, 2019,

Zhengji Zhao, Introduction - The basics of compiling and running on KNL, Cori KNL: Programming and Optimization, Cray KNL training, April 16-18, 2018, Berkeley CA, April 16, 2019,

Zhengji Zhao, Introduction: The basics of compiling and running jobs on KNL, Cori KNL: Programming and Optimization, Cray Training, Feb 12-13, 2019, Berkeley CA, February 12, 2019,

Zhengji Zhao, Transition from Edison to Cori KNL How to compile and run on KNL, Edison to KNL User Training, December 12, 2018, Berkeley CA, December 12, 2018,

Tianmu Xin, ​Zhengji Zhao​, Yue Hao, Binping Xiao, Qiong Wu, Alexander Zaltsman, Kevin Smith, and Xinmin Tian, Performance Tuning to close Ninja Gap for Accelerator Physics Emulation System (APES) on Intel Xeon Phi Processors, A talk presented in the 14th ​International Workshop on OpenMP (​IWOMP18​), Barcelona Spain, September 26, 2018,

Benjamin Driscoll, and Zhengji Zhao, Automating NERSC Reporting, 2018 CS Summer Student POSTER SESSION, August 2, 2018, Berkeley CA, August 2, 2018,

Zhengji Zhao, Using VASP at NERSC, Chemistry and Materials Science Application Training, Berkeley CA, June 29, 2018,

Zhengji Zhao, New User Training: March 21, 2018, New User Training, March 21, 2018, Berkeley CA, March 21, 2018,

Yun (Helen) He, Steve Leak, and Zhengji Zhao, Using Cori KNL Nodes, Cori KNL Training, Berkeley, CA., June 9, 2017,

Douglas Jacobsen, and ​Zhengji Zhao, Instrumenting Slurm User Commands to Gain Workload Insight, Proceeding of the ​Cray User Group Meeting (​CUG18​), Stockholm, Sweden, May 20, 2017,

Luther Martin, and Zhengji Zhao, Optimization Strategies for Materials Science Applications on Cori: An Intel Knights Landing, Many Integrated Core Architecture, ACM Student Research Competition in SC15, (Luther Martin won a Silver Medal), http://sc15.supercomputing.org/, November 15, 2015,

Zhengji Zhao, Scott French, Jack Deslippe, Mathias Jacquelin, Brian Friesen, and Helen He, Application Readiness for NERSC Cori, Berkeley Lab CS Strategic Review 2015, September 9, 2015,

Zhengji Zhao, Using VASP at NERSC, NERSC User Training, Oakland, CA, June 5, 2015,

Zhengji Zhao, Intel Tools for Optimizations, A talk given at Cray Quarterly Business Review Meeting, St. Paul, MN, April 8, 2015,

Zhengji Zhao, A Burst Buffer Use Case, Cray Quarterly Business Review Meeting, Oakland, CA, January 28, 2015,

Zhengji Zhao, Cori and NERSC Exascale Application Program (NESAP), NWChem Developers Workshop at Seattle, WA, October 28, 2014,

Zhengji Zhao, Automatic Library Tracking Database at NERSC, ALTD Review Meeting at NERSC, Oakland CA, October 8, 2014,

Zhengji Zhao, Quality and Testing of PE releases, Cray Quarterly Business Meeting, Oakland CA, July 30, 2014,

Zhengji Zhao, Doug Petesch, David Knaak, and Tina Declerck, I/O Performance on Cray XC30, Cray User Group Meeting, May 4-8, 2014, Lugano, Switzerland, May 4, 2014,

Zhengji Zhao, NERSC, Best Practices for Best Performance on Edison, February 6, 2014,

Zhengji Zhao, NERSC, Available Software at NERSC, February 3, 2014,

Richard A Gerber, Zhengji Zhao, NERSC Job Data, November 20, 2013,

Zhengji Zhao, Process and Thread Affinity with OpenMP, NERSC User Training on Edison Performance, Oakland, CA, October 10, 2013,

Zhengji Zhao, Edison Phase I Early User Science Results, A brown bag talk at NERSC, Oakland CA; Cray Quarterly Business Review Meeting, St. Paul, MN, July 22, 2013,

Richard A. Gerber, Tina Declerck. Zhengji Zhao, Edison Update, February 12, 2013,

Overview and update on the installation and configuration of Edison, NERSC's new Cray XC30 supercomputer.

Zhengji Zhao, Megan Bowling, and Jack Deslippe, Using Cray Compilers at NERSC - Usability and Performance, Cray Quarterly Business Review Meeting, Oakland, CA, July 25, 2012,

Zhengji Zhao, Introduction to Materials Science and Chemistry Applications at NERSC, NERSC User Training Event, Oakland CA, June 26, 2012,

Zhengji Zhao, Application and Development Software, A talk given at the N7 design review meeting, Oakland, CA, May 10, 2012,

Megan Bowling, Zhengji Zhao and Jack Deslippe, The Effects of Compiler Optimizations on Materials Science and Chemistry Applications at NERSC, A talk in the Cray User Group meeting, Apri 29-May-3, 2012, Stuttgart, German., May 3, 2012,

Zhengji Zhao, Mike Davis, Katie Antypas, Yushu Yao, Rei Lee and Tina Butler, Shared Library Performance on Hopper, A talk in the Cray User Group meeting, Apri 29-May-3, 2012, Stuttgart, German., May 3, 2012,

Zhengji Zhao, Yun (Helen) He and Katie Antypas, Cray Cluster Compatibility Mode on Hopper, A talk in the Cray User Group meeting, April 29-May-3, 2012, Stuttgart, German., May 1, 2012,

Zhengji Zhao and Helen He, Using Cray Cluster Compatibility Mode on Hopper, A talk NERSC User Group meeting, Feb 2, 2012, Oakland, CA, February 2, 2012,

Zhengji Zhao and Helen He, Cray Cluster Compatibility Mode on Hopper, A Brown Bag Lunch talk at NERSC, Dec. 8, 2011, Oakland, CA, December 8, 2011,

Zhengji Zhao, Mike Davis, Katie Antypas, Rei Lee and Tina Butler, Shared Library Performance on Hopper, Oct. 26, 2011, Cray Quarterly Meeting at St Paul, MN, October 26, 2011,

Zhengji Zhao and Nick Wright, Performance of Density Functional Theory codes on Cray XE6, A talk in Cray User Group meeting 2011, May 23-26, 2011, Fairbanks, Alaska., May 23, 2011,

Zhengji Zhao, Introduction to Materials Science and Chemistry Applications at NERSC, NERSC User Training, April 5, 2011, Oakland, CA, April 5, 2011,

Zhengji Zhao, Tips to Compile Materials Science and Chemistry Codes at NERSC, NERSC User Training, April 5, 2011, Oakland, CA., April 5, 2011,

Rob Cunningham, Zhengji Zhao, Compiling Code on the XE6, A talk at NERSC Cray XE6 user training, Feb 7-8, 2011, Oakland, CA., February 7, 2011,

Zhengji Zhao, Overview NERSC Facilities and Usage, A talk at Workshop on Leadership-class Machines, Petascale Applications, and Performance Strategies, July 19–22, 2010, Snowbird, Utah, July 21, 2010,

Zhengji Zhao, Node mapping and the parallel performance of the LS3DF code on BG/P, An invited talk at ScicomP 16, May10-14, 2010,San Francesco, CA., May 10, 2010,

Zhengji Zhao, Juan Meza, Byounghak Lee, Hongzhang Shan, Erich Strohmaier, David Bailey, Linearly Scaling 3D Fragment Method for Large-Scale Electronic Structure Calculations, An invited poster presentation in SciDac meeting, June 14-18, 2009, San Diego, CA., June 14, 2009,

Zhengji Zhao, and Lin-Wang Wang, The application of the LS3DF method to CdSe/CdS core/shell structures, A talk at Cray User Group meeting, May 4-7, 2009, Atlanta, GA., May 5, 2009,

Lin-Wang Wang, Byounghak Lee, Zhengji Zhao, Hongzhang Shan, Juan Meza, Erich Strohmaier, David Bailey, Linearly Scaling 3D Fragment Method for Large-Scale Electronic Structure Calculations, An invited talk at Cray Technical Workshop North America, February 24-25, 2009, Charleston, SC., February 24, 2009,

Lin-Wang Wang, Byounghak Lee, Zhengji Zhao, Hongzhang Shan, Juan Meza, Erich Strohmaier and David Bailey, Linearly Scaling 3D Fragment Method for Large-Scale Electronic Structure Calculations, A talk in SC08, Nov 20, 2008, Austin, Texas., November 20, 2008,

Zhengji Zhao, Lin-Wang Wang and Juan Meza, A New O(N) Method for Petascale Nanoscience Simulations, the ACM Best poster (SC07) at International Conferences for High Performance Computing, Networking, Storage and Analysis,Nov. 10-16, 2007, Reno, CA., November 10, 2007,

Zhengji Zhao, Third Party Software, A talk at NERSC User Meeting, Sept. 17, 2007, Oakland, CA., September 17, 2007,

Zhengji Zhao, Lin-Wang Wang, and Juan Meza, The linear scaling 3-dimensional fragment method for petascale nanoscience simulations, A poster presented in STANFORD 50: State of the Art & Future Directions of Computational Mathematics & Numerical Computing, March 29-31, 2007, Palo Alto, California., May 29, 2007,

Zhengji Zhao, Lin-Wang Wang, and Juan Meza, A Linear Scaling 3-Dimensional Fragment Method for Petascale Nanoscience Simulations, A poster presented in Office of Advanced Scientific Computing Research (OSCAR) 2007 Applied Mathematics PI Meeting, May 22 - 24, 2007, Livermore, CA., May 22, 2007,

Zhengji Zhao, Lin-Wang Wang, and Juan Meza, Linear Scaling NanoScience Simulations for Petascale Computing, A talk presented in APS March 5-9, 2007, Denver, Colorado., March 5, 2007,

Zhengji Zhao, Lin-Wang Wang, and Juan Meza, Linear Scaling 3D Fragment Method for Petascale Nanoscience Simulations, A poster presented in SIAM Computational Science and Engineering (CSE), Feb 19-23, 2007, Costa Mesa, California., February 19, 2007,

Zhengji Zhao, Lin-Wang Wang, and Juan Meza, Linear Scaling NanoScience Simulations for Petascale Computing,, An invited talk in the HPC for Nano-science and Technology workshop, International Conference for High Performance Computing, Nov. 11-17, 2006, Tampa, FL., November 17, 2006,

Reports

Zhengji Zhao, Rebecca Hartman-Baker, "Checkpoint/Restart Vision and Strategies for NERSC’s Production Workloads", https://escholarship.org/uc/item/48v5r5rj, August 20, 2021,

K. Antypas, B.A Austin, T.L. Butler, R.A. Gerber, C.L Whitney, N.J. Wright, W. Yang, Z Zhao, "NERSC Workload Analysis on Hopper", Report, October 17, 2014, LBNL 6804E,