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  • Japan’s Fugaku gains title as world’s fastest supercomputer
  • Fugaku has a new façade
  • Delivery of the Supercomputer Fugaku has been Completed
  • Supercomputer Fugaku will be used to help fight against COVID-19
  • RIKEN Center for Computational Science

The 198th R-CCS Cafe -partⅠ
Date and Time: Fri. Sep. 11, 2020, 16:00 - 16:20
(17:00 - 17:20 Discussion (speakers are requested to participate; we will take a 1-2 min. break in the beginning))
Place: Online seminar on BlueJeans

If you are not affiliated with R-CCS and would like to attend R-CCS Cafe, please email us at r-ccs-cafe[at]ml.riken.jp.

Title: Toward a whole-brain simulation on the supercomputer Fugaku
Speaker: Jun Igarashi (High Performance Artificial Intelligence Systems Research Team)

Presentation Language: English
Presentation Material: English

Abstract:Detail

A whole-brain simulation allows us to investigate all interactions among neurons in the brain to understand the mechanisms of information processing and brain diseases. However, the whole-brain simulation has not been realized so far due to a lack of physiological data and computational resources. The supercomputer Fugaku is estimated to perform the whole-brain simulation on a human-scale due to its computational performance. To realize the whole-brain simulation and understand the brain's mechanism, we have worked in Post-K exploratory challenge 4-1 and started a new project of the Fugaku since April 2020. In the projects, we constructed a minimum unit of mammalian brain model consisting of the cerebral cortex, basal ganglia, cerebellum, and thalamus, which reproduced resting-state neural activity. We also have been developing an in-house neural network simulator, MONET, that can utilize the wide SIMD and many cores of A64FX of the Fugaku. The MONET simulator simulated models of the cerebral cortex with 5 billion neurons and cerebellum with 64 billion on the K computer. A recent experiment showed that MONET realized 40 times the more excellent computational performance per compute nodes for simulations of the cerebral cortex and cerebellum on the Fugaku evaluation environment III than the K computer. These results suggest that the full system of the Fugaku may realize whole-brain simulation and contribute to an understanding of the brain.

Important Notes:
- Please turn off your video and microphone when you join the meeting. - The broadcasting may be interrupted or terminated depending on the network condition or any other unexpected event. - The program schedule and contents may be modified without prior notice. - Depending on the utilized device and network environment, it may not be able to watch the session. - All rights concerning the broadcasted material will belong to the organizer and the presenters, and it is prohibited to copy, modify, or redistribute the total or a part of the broadcasted material without the previous permission of RIKEN.

The 198th R-CCS Cafe -partⅡ
Date and Time: Fri. Sep. 11, 2020, 16:20 - 16:40
(17:00 - 17:20 Discussion (speakers are requested to participate; we will take a 1-2 min. break in the beginning))
Place: Online seminar on BlueJeans

If you are not affiliated with R-CCS and would like to attend R-CCS Cafe, please email us at r-ccs-cafe[at]ml.riken.jp.

Title: Toward Accurate and Reproducible Numerical Computations
Speaker: Daichi Mukunoki (Large-scale Parallel Numerical Computing Technology Research Team)

Presentation Language: English
Presentation Material: English

Abstract:Detail

We use floating-point numbers for numerical computations in computers. However, as floating-point numbers are represented in finite-precision (usually, 32-bit or 64-bit), the computation has rounding errors. The accumulation may result in inaccuracy of the computation. Moreover, the result can be non-identical at the rounding-error level on different computational environments because the rounding-errors are introduced depending on the order of the computation. Our team studies and develops technologies for addressing those issues to improve the reliability of numerical computations. In this talk, I will introduce several studies that I have been conducting now, including (1) high-precision matrix-multiplications using low-precision operations, (2) accurate and reproducible BLAS and sparse linear solvers, and (3) minimal-precision computing project.

Important Notes:
- Please turn off your video and microphone when you join the meeting. - The broadcasting may be interrupted or terminated depending on the network condition or any other unexpected event. - The program schedule and contents may be modified without prior notice. - Depending on the utilized device and network environment, it may not be able to watch the session. - All rights concerning the broadcasted material will belong to the organizer and the presenters, and it is prohibited to copy, modify, or redistribute the total or a part of the broadcasted material without the previous permission of RIKEN.

The 198th R-CCS Cafe -partⅢ
Date and Time: Fri. Sep. 11, 2020, 16:40 - 17:00
(17:00 - 17:20 Discussion (speakers are requested to participate; we will take a 1-2 min. break in the beginning))
Place: Online seminar on BlueJeans

If you are not affiliated with R-CCS and would like to attend R-CCS Cafe, please email us at r-ccs-cafe[at]ml.riken.jp.

Title: Modelling three-dimensional structures of proteins from tomic-Force Microscopy Images
Speaker: Bhaskar Dasgupta (Computational Structural Biology Research Team)

Presentation Language: English
Presentation Material: English

Abstract:Detail

Atomic Force Microscopy (AFM) is an experimental technique to study structure-function relationship of biomolecules. AFM provides two-dimensional (2D) images of biomolecules at nanometer resolution, however information of three-dimensional (3D) structures is beneficial to understand conformational change often encoded in the images. Our aim is to recover 3D information from an AFM image by computational modeling. In our method we use Monte Carlo sampling, in which candidate models are generated in such a way that the similarity between pseudo-AFM images generated from the models and target AFM image increases gradually. First, we tested our algorithm theoretically on two proteins to model their conformational transitions. Using an AFM image as reference, the algorithm can produce a low-resolution 3D model of the target molecule. Now we are applying our method to experimentally obtained AFM data for a protein Clpb. This is a heat-shock protein with hexameric arrangement and its high-speed AFM images include at least four major classes of structures. So far, we recovered the candidate models corresponding to those structural classes enabling us to realize 3D representations encoded in these AFM images. The new AFM based hybrid modeling method would be useful to retrieve 3D information of a biomolecule, therefore we could study how 3D structures of biomolecules are dictating its function. Moreover, from the analysis of the reconstructed models it is possible to understand in more detail the conformational transitions of proteins observed in near physiological condition.

Important Notes:
- Please turn off your video and microphone when you join the meeting. - The broadcasting may be interrupted or terminated depending on the network condition or any other unexpected event. - The program schedule and contents may be modified without prior notice. - Depending on the utilized device and network environment, it may not be able to watch the session. - All rights concerning the broadcasted material will belong to the organizer and the presenters, and it is prohibited to copy, modify, or redistribute the total or a part of the broadcasted material without the previous permission of RIKEN.

The 197th R-CCS Cafe -partⅠ
Date and Time: Mon. Sep. 7, 2020, 16:00 - 16:20
(17:00 - 17:20 Discussion (speakers are requested to participate; we will take a 1-2 min. break in the beginning))
Place: Online seminar on BlueJeans

If you are not affiliated with R-CCS and would like to attend R-CCS Cafe, please email us at r-ccs-cafe[at]ml.riken.jp.

Title: ASURA/FDPS --- Simulation of Galaxy Formation on the supercomputer Fugaku
Speaker: Junichiro Makino (Team Leader, Particle Simulator Research Team)

Presentation Language: English
Presentation Material: English

Abstract:Detail

The goal of the galaxy formation simulation is to follow the formation of galaxies through the whole history of the universe. To achieve this goal, the gravitational dynamics of dark matter, gas and stars, hydrodynamics of gas, star formation process, energy input from stars and supernovae to gas should be modeled properly. Traditionally, the individual timestep algorithm has been used to handle regions with short timescales, such as star-forming regions and supernova shells. However, this algorithm does not scale well for more than 10M particles, because of the need for global communication at each timestep. We have developed a new algorithm to handle regions with short timescales. We report the performance of our new code based on this new algorithm on Supercomputer Fugaku. It scales well for more than 10G particles and more than 100K cores. We also discuss our new DSL for the generation of efficient kernel for particle-particle interaction.

Important Notes:
- Please turn off your video and microphone when you join the meeting. - The broadcasting may be interrupted or terminated depending on the network condition or any other unexpected event. - The program schedule and contents may be modified without prior notice. - Depending on the utilized device and network environment, it may not be able to watch the session. - All rights concerning the broadcasted material will belong to the organizer and the presenters, and it is prohibited to copy, modify, or redistribute the total or a part of the broadcasted material without the previous permission of RIKEN.

The 197th R-CCS Cafe -partⅡ
Date and Time: Mon. Sep. 7, 2020, 16:20 - 16:40
(17:00 - 17:20 Discussion (speakers are requested to participate; we will take a 1-2 min. break in the beginning))
Place: Online seminar on BlueJeans

If you are not affiliated with R-CCS and would like to attend R-CCS Cafe, please email us at r-ccs-cafe[at]ml.riken.jp.

Title: Real-time Demonstration of Big Data Assimilation in Numerical Weather Prediction
Speaker: Takemasa Miyoshi (Team Leader, Data Assimilation Research Team)

Presentation Language: English
Presentation Material: English

Abstract:Detail

The Big Data Assimilation (BDA) project started in October 2013 and ended its 5.5-year period in March 2019. Here, we developed a novel numerical weather prediction (NWP) system at 100-m resolution updated every 30 seconds for precise prediction of individual convective clouds. This system was designed to fully take advantage of the phased array weather radar (PAWR) whose dense and frequent observing capability generates about 100-times bigger data than the regular parabolic antenna radar. By the end of the 5.5-year project period, we achieved less than 30-second computational time using the K computer for past cases with all input data such as boundary conditions and observation data being ready to use. The direct follow-on project started in April 2019 under the Japan Science and Technology Agency (JST) AIP (Advanced Intelligence Project) Acceleration Research. We continued the development to achieve real-time operations of this novel 30-second-update NWP system for demonstration at the time of the Tokyo 2020 Olympic and Paralympic games. The games were postponed, but the project achieved real-time demonstration of the 30-second-update NWP system at 500-m resolution using the Oakforest-PACS supercomputer. A real-time test was performed during July 31 and August 7, 2020 and resulted in the actual lead time of more than 27 minutes for 30-minute prediction with very few exceptions of extended delay. This presentation will summarize the real-time demonstration and provide future perspectives including AI-aided model acceleration for enhancing the system’s portability.

Important Notes:
- Please turn off your video and microphone when you join the meeting. - The broadcasting may be interrupted or terminated depending on the network condition or any other unexpected event. - The program schedule and contents may be modified without prior notice. - Depending on the utilized device and network environment, it may not be able to watch the session. - All rights concerning the broadcasted material will belong to the organizer and the presenters, and it is prohibited to copy, modify, or redistribute the total or a part of the broadcasted material without the previous permission of RIKEN.

The 197th R-CCS Cafe -partⅢ
Date and Time: Mon. Sep. 7, 2020, 16:40 - 17:00
(17:00 - 17:20 Discussion (speakers are requested to participate; we will take a 1-2 min. break in the beginning))
Place: Online seminar on BlueJeans

If you are not affiliated with R-CCS and would like to attend R-CCS Cafe, please email us at r-ccs-cafe[at]ml.riken.jp.

Title: Prediction and Countermeasure for Droplet/Aerosol Infection under the Indoor Environment for the Fight against COVID-19
Speaker: Makoto Tsubokura (Team Leader, Complex Phenomena Unified Simulation Research Team)

Presentation Language: English
Presentation Material: English

Abstract:Detail

Virus droplet infection caused by sneezing, coughing, or talking is strongly influenced by the flow, temperature and humidity of the air around an infected person and potential victims. Especially in the case of the new coronavirus, possibility of aerosol infection by atomized droplets is suggested, in addition to the usual droplet infection. Because smaller aerosol particles drift in the air for a longer time, it is imperative to predict their scattering route and to estimate how surrounding airflow affects the infection. Then the risk of droplet infection can be properly assessed and effective measures to reduce infection can be proposed. In this project, massively parallel coupling simulation of virus droplet scattering, with airflow and heat transfer under the indoor environment such as inside commuter trains, offices, classrooms, and hospital rooms are conducted. By taking into account the characteristics of the virus, its infection risk of virus droplets is assessed under various conditions. Then countermeasures to reduce the risk are proposed from a viewpoint of controlling the air flow. Complex Unified Simulation framework called CUBE, developed at RIKEN R-CCS and implemented on the supercomputer Fugaku, is mainly used, which makes it possible to execute the world-largest and highly accurate virus droplet simulation ever conducted. As the output of this project, the risk of droplet infection under the indoor environment is quantitatively evaluated, and specific countermeasures to reduce the infection risk is proposed in terms of effective ways of opening/closing windows, use of air conditioning, and placement of partitions. These outputs from the simulation can protect the living and working environment from virus droplet infection, and contribute to earlier recovery of our socio-economic activities. This project is supported by the Ministry of Education, Culture, Sports, Science and Technology and RIKEN R-CCS, under the collaboration with RIKEN, Kyoto Institute of Technology, Kobe University, Osaka University, Toyohashi University of Technology, Kajima Corporation, and Daikin Industries, Ltd.

Important Notes:
- Please turn off your video and microphone when you join the meeting. - The broadcasting may be interrupted or terminated depending on the network condition or any other unexpected event. - The program schedule and contents may be modified without prior notice. - Depending on the utilized device and network environment, it may not be able to watch the session. - All rights concerning the broadcasted material will belong to the organizer and the presenters, and it is prohibited to copy, modify, or redistribute the total or a part of the broadcasted material without the previous permission of RIKEN.

The 195th R-CCS Cafe -partⅠ
Date and Time: Mon. Aug. 3, 2020, 16:00 - 16:20
(17:00 - 17:20 Discussion (speakers are requested to participate; we will take a 1-2 min. break in the beginning), 17:20- Free discussion (optional))
Place: Online seminar on BlueJeans

If you are not affiliated with R-CCS and would like to attend R-CCS Cafe, please email us at r-ccs-cafe[at]ml.riken.jp.

Title: High Performance AI on Large Scale Supercomputers
Speaker: Satoshi Matsuoka (Director of R-CCS and Team Leader, High Performance Artificial Intelligence Systems Research Team)

Presentation Language: English
Presentation Material: English

Abstract:Detail

TBA

Important Notes:
- Please turn off your video and microphone when you join the meeting. - The broadcasting may be interrupted or terminated depending on the network condition or any other unexpected event. - The program schedule and contents may be modified without prior notice. - Depending on the utilized device and network environment, it may not be able to watch the session. - All rights concerning the broadcasted material will belong to the organizer and the presenters, and it is prohibited to copy, modify, or redistribute the total or a part of the broadcasted material without the previous permission of RIKEN.

The 195th R-CCS Cafe -partⅡ
Date and Time: Mon. Aug. 3, 2020, 16:20 - 16:40
(17:00 - 17:20 Discussion (speakers are requested to participate; we will take a 1-2 min. break in the beginning), 17:20- Free discussion (optional))
Place: Online seminar on BlueJeans

If you are not affiliated with R-CCS and would like to attend R-CCS Cafe, please email us at r-ccs-cafe[at]ml.riken.jp.

Title: Preliminary Performance Evaluation of XcalableMP on Fugaku and Future
Speaker: Mitsuhisa Sato (Deputy Director of R-CCS and Team Leader, Programming Environment Research Team)

Presentation Language: English
Presentation Material: English

Abstract:Detail

The architecture development team of FS2020 project is working on the performance evaluation of A64FX processor and the evaluation of XcalableMP PGAS programming language which the programming environment research team has been developing for the Fugaku, as well as the K computer and other systems for more than 10 years. In this talk, the preliminary performance of XcalableMP benchmarks on Fugaku will be reported with some future plan for programming models for the Fugaku.

Important Notes:
- Please turn off your video and microphone when you join the meeting. - The broadcasting may be interrupted or terminated depending on the network condition or any other unexpected event. - The program schedule and contents may be modified without prior notice. - Depending on the utilized device and network environment, it may not be able to watch the session. - All rights concerning the broadcasted material will belong to the organizer and the presenters, and it is prohibited to copy, modify, or redistribute the total or a part of the broadcasted material without the previous permission of RIKEN.

The 195th R-CCS Cafe -partⅢ
Date and Time: Mon. Aug. 3, 2020, 16:40 - 17:00
(17:00 - 17:20 Discussion (speakers are requested to participate; we will take a 1-2 min. break in the beginning), 17:20- Free discussion (optional))
Place: Online seminar on BlueJeans

If you are not affiliated with R-CCS and would like to attend R-CCS Cafe, please email us at r-ccs-cafe[at]ml.riken.jp.

Title: Facility and its operation for large scale supercomputer
Speaker: Fumiyoshi Shoji (Division Director, Operations and Computer Technologies Division and Unit Leader, HPC Usability Development Unit)

Presentation Language: English
Presentation Material: English

Abstract:Detail

The computing performance of the large-scale supercomputer is still growing even near the end of Moore's low. It is not easy to suppress the increase of the power consumption while growing up the performance. To reduce power consumption, many technologies have been developed and implemented ―for example, Hot-water cooling and Dynamic Voltage and Frequency Scaling (DVFS). The former is the technique to reduce cooling energy by using higher temperature cooling water, which can be cooled by outside air. The latter is a technique to cap CPU power consumption by automatic controlling the voltage and frequency depending on the load and the temperature of the CPU. The combination of the Hot-water cooling and DVFS is widely adopted to many large-scale systems and HPC centers. However, in the energy-saving aspect, it is non-trivial to show that this combination is effective. Because when Hot-water cooling and DVFS works, computing performance degradation will occur. In that case, we might need more energy to recover degradation. In this talk, I would like to introduce this issue in detail and our approach.

Important Notes:
- Please turn off your video and microphone when you join the meeting. - The broadcasting may be interrupted or terminated depending on the network condition or any other unexpected event. - The program schedule and contents may be modified without prior notice. - Depending on the utilized device and network environment, it may not be able to watch the session. - All rights concerning the broadcasted material will belong to the organizer and the presenters, and it is prohibited to copy, modify, or redistribute the total or a part of the broadcasted material without the previous permission of RIKEN.

The 194th R-CCS Cafe -partⅠ
Date and Time: Fri. July. 10, 2020, 16:00 - 16:20
(17:05 - 17:20 Free discussion with speakers, 17:20- Free discussion)
Place: Online seminar on BlueJeans

If you are not affiliated with R-CCS and would like to attend R-CCS Cafe, please email us at r-ccs-cafe[at]ml.riken.jp.

Title: Role of Spin-Orbit Coupling in the Magnetic Anisotropy of Metal Complexes
Speaker: Sabyasachi Roy Chowdhury (Computational Molecular Science Research Team)

Presentation Language: English
Presentation Material: English

Abstract:Detail

In the search for single molecule magnets, metal ions are considered pivotal towards achieving large magnetic anisotropy barriers. Linear or near‐linear bi-coordinate mononuclear Co(II) complexes are studied as potential single‐molecule magnets owing to the strong spin-orbit coupling constant of Co(II) and its low coordination number, which results in the retention of the unquenched metal‐orbital angular momentum [1]. The spin-orbit coupled unquenched orbital angular momentum of the metal centre produces strong magnetic anisotropy through ligand‐field interactions. In this context, the influence of ligands with heavy elements, showing large spin–orbit coupling, on magnetic anisotropy barriers was investigated using a series of Mn(II)-based complexes, in which the metal ion did not have any orbital contribution. The mixing of metal and ligand orbitals was achieved by explicitly correlating the metal and ligand valence electrons with CASSCF calculations. The CASSCF wave functions were further used for evaluating spin–orbit coupling and zero-field splitting parameters for these complexes. For Mn(II) complexes with heavy ligand atoms, such as Br and I, several interesting inter-state mixings occur via the spin–orbit operator, which results in large magnetic anisotropy in these Mn(II) complexes [2].
[1] S. Roy Chowdhury and S. Mishra Eur. J. Inorg. Chem. (2017) 659-668.
[2] S. Roy Chowdhury and S. Mishra Phys. Chem. Chem. Phys. 19 (2017) 16914-16922.

Important Notes:
- When the speaker is talking, please mute your microphone.
- The broadcasting can be interrupted or terminated depending on the network condition or any other unexpected event.
- The program schedule and contents can be modified without prior notice.
- Depending on the utilized device and network environment, it may not be able to watch the session.
- All rights concerning the broadcasted material will belong to the organizer and the presenters, and it is prohibited to copy, modify, or redistribute the total or a part of the broadcasted material without the previous permission of RIKEN.