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138 results on '"Karmakar, Anupam"'

3. Optimizing the hybrid parallelization of BHAC

Author

Cielo, Salvatore, Porth, Oliver, Iapichino, Luigi, Karmakar, Anupam, Olivares, Hector, and Xia, Chun

Subjects
Computer Science - Distributed, Parallel, and Cluster Computing, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

We present our experience with the modernization on the GR-MHD code BHAC, aimed at improving its novel hybrid (MPI+OpenMP) parallelization scheme. In doing so, we showcase the use of performance profiling tools usable on x86 (Intel-based) architectures. Our performance characterization and threading analysis provided guidance in improving the concurrency and thus the efficiency of the OpenMP parallel regions. We assess scaling and communication patterns in order to identify and alleviate MPI bottlenecks, with both runtime switches and precise code interventions. The performance of optimized version of BHAC improved by $\sim28\%$, making it viable for scaling on several hundreds of supercomputer nodes. We finally test whether porting such optimizations to different hardware is likewise beneficial on the new architecture by running on ARM A64FX vector nodes., Comment: 10 pages, 9 figures, 1 table; in review

Published
2021

4. Comparative Analysis of Normal and Anemic RBC by Employing Impedimetric and Voltammetric Studies

Author

Bhattacharya, Debopam, Roy, Aindrila, Das, Chirantan, Nag Chowdhury, Basudev, Karmakar, Anupam, Chattopadhyay, Sanatan, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Hirche, Sandra, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Möller, Sebastian, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Zhang, Junjie James, Series Editor, Giri, Chandan, editor, Iizuka, Takahiro, editor, Rahaman, Hafizur, editor, and Bhattacharya, Bhargab B., editor

Published
2023
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5. Voltammetric Detection and Controlled Inhibition of Decarboxylation of Gallic Acid (GA) in Green Tea Using Eugenol

Author

Roy, Aindrila, Bhattacharya, Debopam, Das, Chirantan, Nag Chowdhury, Basudev, Karmakar, Anupam, Chattopadhyay, Sanatan, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Hirche, Sandra, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Möller, Sebastian, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Zhang, Junjie James, Series Editor, Giri, Chandan, editor, Iizuka, Takahiro, editor, Rahaman, Hafizur, editor, and Bhattacharya, Bhargab B., editor

Published
2023
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10. Extreme Scale-out SuperMUC Phase 2 - lessons learned

Author

Hammer, Nicolay, Jamitzky, Ferdinand, Satzger, Helmut, Allalen, Momme, Block, Alexander, Karmakar, Anupam, Brehm, Matthias, Bader, Reinhold, Iapichino, Luigi, Ragagnin, Antonio, Karakasis, Vasilios, Kranzlmüller, Dieter, Bode, Arndt, Huber, Herbert, Kühn, Martin, Machado, Rui, Grünewald, Daniel, Edelmann, Philipp V. F., Röpke, Friedrich K., Wittmann, Markus, Zeiser, Thomas, Wellein, Gerhard, Mathias, Gerald, Schwörer, Magnus, Lorenzen, Konstantin, Federrath, Christoph, Klessen, Ralf, Bamberg, Karl-Ulrich, Ruhl, Hartmut, Schornbaum, Florian, Bauer, Martin, Nikhil, Anand, Qi, Jiaxing, Klimach, Harald, Stüben, Hinnerk, Deshmukh, Abhishek, Falkenstein, Tobias, Dolag, Klaus, and Petkova, Margarita

Subjects
Computer Science - Distributed, Parallel, and Cluster Computing, Astrophysics - Instrumentation and Methods for Astrophysics, Physics - Computational Physics, Physics - Fluid Dynamics
Abstract

In spring 2015, the Leibniz Supercomputing Centre (Leibniz-Rechenzentrum, LRZ), installed their new Peta-Scale System SuperMUC Phase2. Selected users were invited for a 28 day extreme scale-out block operation during which they were allowed to use the full system for their applications. The following projects participated in the extreme scale-out workshop: BQCD (Quantum Physics), SeisSol (Geophysics, Seismics), GPI-2/GASPI (Toolkit for HPC), Seven-League Hydro (Astrophysics), ILBDC (Lattice Boltzmann CFD), Iphigenie (Molecular Dynamic), FLASH (Astrophysics), GADGET (Cosmological Dynamics), PSC (Plasma Physics), waLBerla (Lattice Boltzmann CFD), Musubi (Lattice Boltzmann CFD), Vertex3D (Stellar Astrophysics), CIAO (Combustion CFD), and LS1-Mardyn (Material Science). The projects were allowed to use the machine exclusively during the 28 day period, which corresponds to a total of 63.4 million core-hours, of which 43.8 million core-hours were used by the applications, resulting in a utilization of 69%. The top 3 users were using 15.2, 6.4, and 4.7 million core-hours, respectively., Comment: 10 pages, 5 figures, presented at ParCo2015 - Advances in Parallel Computing, held in Edinburgh, September 2015. The final publication is available at IOS Press through http://dx.doi.org/10.3233/978-1-61499-621-7-827

Published
2016
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12. Optimising PICCANTE - an Open Source Particle-in-Cell Code for Advanced Simulations on Tier-0 Systems

Author

Sgattoni, Andrea, Fedeli, Luca, Sinigardi, Stefano, Marocchino, Alberto, Macchi, Andrea, Weinberg, Volker, and Karmakar, Anupam

Subjects
Computer Science - Distributed, Parallel, and Cluster Computing, Physics - Computational Physics, Physics - Plasma Physics
Abstract

We present a detailed strong and weak scaling analysis of PICCANTE, an open source, massively parallel, fully-relativistic Particle-In-Cell (PIC) code. PIC codes are widely used in plasma physics and astrophysics to study the cases where kinetic effects are relevant. PICCANTE is primarily developed to study laser-plasma interaction. Within a PRACE Preparatory Access Project, various revisions of different routines of the code have been analysed on the HPC systems JUQUEEN at Juelich Supercomputing Centre (JSC), Germany, and FERMI at CINECA, Italy, to improve scalability and I/O performance of the application. The diagnostic tool Scalasca is used to identify suboptimal routines. Different output strategies are discussed. The detailed strong and weak scaling behaviour of the improved code are presented in comparison with the original version of the code., Comment: 8 pages, 6 figures, PRACE Whitepaper

Published
2015

17. Analyzing the I/O Scalability of a Parallel Particle-in-Cell Code

Author

Mendez, Sandra, Hammer, Nicolay J., Karmakar, Anupam, Hutchison, David, Series Editor, Kanade, Takeo, Series Editor, Kittler, Josef, Series Editor, Kleinberg, Jon M., Series Editor, Mattern, Friedemann, Series Editor, Mitchell, John C., Series Editor, Naor, Moni, Series Editor, Pandu Rangan, C., Series Editor, Steffen, Bernhard, Series Editor, Terzopoulos, Demetri, Series Editor, Tygar, Doug, Series Editor, Yokota, Rio, editor, Weiland, Michèle, editor, Shalf, John, editor, and Alam, Sadaf, editor

Published
2018
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33. Investigating the quasi-oscillatory behavior of electrical parameters with the concentration of D-glucose in aqueous solution

Author

Chakraborty Subhadip, Das Chirantan, Saha Rajib, Das Avishek, Bera Nirmal Kumar, Chattopadhyay Dipankar, Karmakar Anupam, Chattopadhyay Dhrubajyoti, and Chattopadhyay Sanatan

Subjects
quasi-oscillatory nature, di water-glucose, polar solution, multi-body dipole correlation, dipole polarization, impedance spectroscopy, Medicine (General), R5-920
Abstract

The impedance, capacitance and conductance of deionized water-glucose polar solution is measured by employing impedance spectroscopy and a quasi-oscillatory nature of variation with glucose content in the solution is observed. Such quasi-oscillatory nature is attributed to the randomly distributed water-water, water-glucose and glucose-glucose dipole interactions at the molecular level in the solution. A relevant analytical model is developed on the basis of such random distribution of the molecular dipoles and the experimental data agree well with those obtained from the theoretical model. The electrical parameters are measured in the frequency range of 100Hz to 4MHz for the volume fractions of glucose with respect to water in the range of 0.1 to 0.5. The impedance, capacitance and conductance are obtained to be in the range of 1.03 kΩ – 112 kΩ, 34.9 pF – 1.66 nF, and 8.95 μS – 52.9 μS respectively for the glucose volume fraction range considered.

Published
2015
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36. Investigation of Yttrium (Y)-doped ZnO (Y:ZnO)–Ga2O3 core-shell nanowire/Si vertical heterojunctions for high-performance self-biased wideband photodetectors.

Author

Saha, Rajib, Chakrabarti, Subhananda, Karmakar, Anupam, and Chattopadhyay, Sanatan

Abstract

High interfacial area, less surface defects and wide light absorption capability of core-shell nanowire heterojunctions are broadly accepted as a potential candidate for self-biased, high-speed photodetectors. In the current study, Y:ZnO–Ga2O3 core-shell nanowires' heterojunctions are fabricated by employing sequential double-step chemical bath deposition (CBD) and radio -frequency (RF) sputtering techniques on Si substrate. The ultra-thin highly transparent Ga2O3 (~ 15 nm) layer reduces the surface states of Y:ZnO nanowires in a significant amount and such core-shell heterojunction deals with the development of low power white light-responsive detectors by combining Y:ZnO and Ga2O3. The crystallinity, structure, chemical states and light absorption properties of the Y:ZnO–Ga2O3 core-shell nanowires are analysed in detail by using XRD, FESEM, HRTEM, EDS, XPS and UV-Visible spectroscopy. The fabricated core-shell Y:ZnO–Ga2O3 nanowire/Si heterojunction exhibits p–n junction behaviour and it exhibits self-powered photoresponse under Xe lamp with AM 1.5 G (100 W/cm2) filter. A low dark current of ~ 1.74 × 10− 11 A, high photo-to-dark current ratio of 3.2 × 104 and rapid response speed of < 1 s are achieved from such core-shell heterojunction device and relevant photo-carrier generation mechanism is considered from energy band diagram. Therefore, current study provides a technological route to fabricate the next-generation self-powered core-shell heterojunction devices for photo-sensing applications. [ABSTRACT FROM AUTHOR]

Published
2023
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