Journal articles: 'Lattice code'

1

Damen, O., A. Chkeif, and J. C. Belfiore. "Lattice code decoder for space-time codes." IEEE Communications Letters 4, no. 5 (May 2000): 161–63. http://dx.doi.org/10.1109/4234.846498.

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Mathis, Alexander, Andreas V. M. Herz, and Martin Stemmler. "Optimal Population Codes for Space: Grid Cells Outperform Place Cells." Neural Computation 24, no. 9 (September 2012): 2280–317. http://dx.doi.org/10.1162/neco_a_00319.

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Rodents use two distinct neuronal coordinate systems to estimate their position: place fields in the hippocampus and grid fields in the entorhinal cortex. Whereas place cells spike at only one particular spatial location, grid cells fire at multiple sites that correspond to the points of an imaginary hexagonal lattice. We study how to best construct place and grid codes, taking the probabilistic nature of neural spiking into account. Which spatial encoding properties of individual neurons confer the highest resolution when decoding the animal's position from the neuronal population response? A priori, estimating a spatial position from a grid code could be ambiguous, as regular periodic lattices possess translational symmetry. The solution to this problem requires lattices for grid cells with different spacings; the spatial resolution crucially depends on choosing the right ratios of these spacings across the population. We compute the expected error in estimating the position in both the asymptotic limit, using Fisher information, and for low spike counts, using maximum likelihood estimation. Achieving high spatial resolution and covering a large range of space in a grid code leads to a trade-off: the best grid code for spatial resolution is built of nested modules with different spatial periods, one inside the other, whereas maximizing the spatial range requires distinct spatial periods that are pairwisely incommensurate. Optimizing the spatial resolution predicts two grid cell properties that have been experimentally observed. First, short lattice spacings should outnumber long lattice spacings. Second, the grid code should be self-similar across different lattice spacings, so that the grid field always covers a fixed fraction of the lattice period. If these conditions are satisfied and the spatial “tuning curves” for each neuron span the same range of firing rates, then the resolution of the grid code easily exceeds that of the best possible place code with the same number of neurons.

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KENDZIORRA, ANDREAS, and STEFAN E. SCHMIDT. "NETWORK CODING WITH MODULAR LATTICES." Journal of Algebra and Its Applications 10, no. 06 (December 2011): 1319–42. http://dx.doi.org/10.1142/s0219498811005208.

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Kötter and Kschischang presented in 2008 a new model for error correcting codes in network coding. The alphabet in this model is the subspace lattice of a given vector space, a code is a subset of this lattice and the used metric on this alphabet is the map d : (U, V) ↦ dim (U+V)- dim (U∩V). In this paper we generalize this model to arbitrary modular lattices, i.e. we consider codes, which are subsets of modular lattices. The used metric in this general case is the map d : (u, v) ↦ h(u ∨ v) - h(u ∧ v), where h is the height function of the lattice. We apply this model to submodule lattices. Moreover, we show a method to compute the size of spheres in certain modular lattices and present a sphere packing bound, a sphere covering bound, and a Singleton bound for codes, which are subsets of modular lattices.

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Choi, Sooyoung, Azamat Khassenov, and Deokjung Lee. "ICONE23-1905 RESONANCE INTERFERENCE METHOD IN LATTICE PHYSICS CODE STREAM." Proceedings of the International Conference on Nuclear Engineering (ICONE) 2015.23 (2015): _ICONE23–1—_ICONE23–1. http://dx.doi.org/10.1299/jsmeicone.2015.23._icone23-1_430.

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Jain, Sapna. "Singleton's Bound in Euclidean Codes." Algebra Colloquium 17, spec01 (December 2010): 741–48. http://dx.doi.org/10.1142/s1005386710000714.

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There are three standard weight functions on a linear code viz. the Hamming weight, Lee weight and Euclidean weight. The Euclidean weight function is useful in connection with the lattice constructions, where the minimum norm of vectors in the lattice is related to the minimum Euclidean weight of the code. In this paper, we obtain Singleton's bound for Euclidean codes and introduce maximum Euclidean square distance separable (MESDS) codes.

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Wan, Qian, Kai Niu, and Jia Ru Lin. "K-Best Sphere Decoding of Lattice Codes Based on CRC Code." Applied Mechanics and Materials 321-324 (June 2013): 2864–67. http://dx.doi.org/10.4028/www.scientific.net/amm.321-324.2864.

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This work proposes a CRC-aided K-best sphere decoding scheme to improve the performance of lattice codes. The generator of the lattice is designed as to be an upper triangular, which is naturally suited for sphere decoding. When the K is sufficiently large, the naïve K-best sphere decoding can approach the lower bound of block error rate (BLER) of maximum likelihood (ML). Therefore, the proposed scheme can outperforms the naïve K-best sphere decoding with the assistance of CRC code.

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Conway, J., and N. Sloane. "Soft decoding techniques for codes and lattices, including the Golay code and the Leech lattice." IEEE Transactions on Information Theory 32, no. 1 (January 1986): 41–50. http://dx.doi.org/10.1109/tit.1986.1057135.

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Krause, Mathias J., Adrian Kummerländer, Samuel J. Avis, Halim Kusumaatmaja, Davide Dapelo, Fabian Klemens, Maximilian Gaedtke, et al. "OpenLB—Open source lattice Boltzmann code." Computers & Mathematics with Applications 81 (January 2021): 258–88. http://dx.doi.org/10.1016/j.camwa.2020.04.033.

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9

Harada, Masaaki, and Masaaki Kitazume. "Z6-Code Constructions of the Leech Lattice and the Niemeier Lattices." European Journal of Combinatorics 23, no. 5 (July 2002): 573–81. http://dx.doi.org/10.1006/eujc.2002.0557.

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10

Horsman, Clare, Austin G. Fowler, Simon Devitt, and Rodney Van Meter. "Surface code quantum computing by lattice surgery." New Journal of Physics 14, no. 12 (December 7, 2012): 123011. http://dx.doi.org/10.1088/1367-2630/14/12/123011.

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11

She, Ding, Zhihong Liu, and Jing Zhao. "The Laputa code for lattice physics analyses." Annals of Nuclear Energy 75 (January 2015): 303–8. http://dx.doi.org/10.1016/j.anucene.2014.08.050.

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Kim, W. Y., and B. J. Min. "Assessment of WIMS-D5 Applicability to CANDU NPPs." Key Engineering Materials 277-279 (January 2005): 741–46. http://dx.doi.org/10.4028/www.scientific.net/kem.277-279.741.

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The purpose of this study is to develop a WIMS/CANDU code for a lattice calculation on the basis of WIMS-D5 code for the safety analysis of CANDU reactors. To assess WIMS-D5 applicability to a CANDU reactor, a lattice model was developed for CANDU-6 reactors at the Wolsong site. As for the benchmark of the code validation, a code-to-code comparison was performed between the WIMS-D5 code with both the 69- and 172-energy groups of ENDF/B-VI nuclear data library and the WIMS-AECL code with the 89-energy group. The comparison studies of the reactor physics parameters such as the void reactivity and the coolant/fuel/moderator temperature coefficients were conducted with a change of the internal isotopic composition due to the fuel burning-up using both WIMS-AECL and POWDERPUFS-V (PPV) codes. The results show that the present results from WIMS-D5 code and WIMS-AECL code agreed well with those of the PPV at the beginning of the fuel burn-up phase. As the burning-up progresses, the results of WIMS-D5 show a large deviation from those of PPV for the CANDU 6 reactors.

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Bi, Yujiang, Yi Xiao, WeiYi Guo, Ming Gong, Peng Sun, Shun Xu, and Yi-bo Yang. "Lattice QCD GPU Inverters on ROCm Platform." EPJ Web of Conferences 245 (2020): 09008. http://dx.doi.org/10.1051/epjconf/202024509008.

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The open source ROCm/HIP platform for GPU computing provides a uniform framework to support both the NVIDIA and AMD GPUs, and also the possibility to porting the CUDA code to the HIP-compatible one. We present the porting progress on the Overlap fermion inverter (GWU-code) and also the general Lattice QCD inverter package - QUDA. The manual of using QUDA on HIP and also the tips of porting general CUDA code into the HIP framework are also provided.

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14

Nagayama, Shota, Austin G. Fowler, Dominic Horsman, Simon J. Devitt, and Rodney Van Meter. "Surface code error correction on a defective lattice." New Journal of Physics 19, no. 2 (February 23, 2017): 023050. http://dx.doi.org/10.1088/1367-2630/aa5918.

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15

Vuillot, Christophe, Lingling Lao, Ben Criger, Carmen García Almudéver, Koen Bertels, and Barbara M. Terhal. "Code deformation and lattice surgery are gauge fixing." New Journal of Physics 21, no. 3 (March 28, 2019): 033028. http://dx.doi.org/10.1088/1367-2630/ab0199.

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16

Viterbo, E., and J. Bouros. "A universal lattice code decoder for fading channels." IEEE Transactions on Information Theory 45, no. 5 (July 1999): 1639–42. http://dx.doi.org/10.1109/18.771234.

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17

GOHAIN, NISHA, TAZID ALI, and ADIL AKHTAR. "LATTICE STRUCTURE AND DISTANCE MATRIX OF GENETIC CODE." Journal of Biological Systems 23, no. 03 (August 30, 2015): 485–504. http://dx.doi.org/10.1142/s0218339015500254.

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The genetic code is the rule by which DNA stores the genetic information about formation of protein molecule. In this paper, a partial ordering is equipped on the genetic code and a lattice structure has been developed from it. The codon–anticodon interaction, hydrogen bond number and the chemical types of bases play an important role in the partial ordering. We have established some relations between the lattice structure of the genetic code and physico-chemical properties of amino acids. Taking into consideration the evolutionary importance of base positions in codons we have constructed a distance matrix for the amino acids. Further with a real life example we have demonstrated the relationship between frequently occurring mutations and codon distances.

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She, Ding, Zhihong Liu, and Lei Shi. "XPZ: Development of a lattice code for HTR." Annals of Nuclear Energy 97 (November 2016): 183–89. http://dx.doi.org/10.1016/j.anucene.2016.07.017.

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19

de Beaudrap, Niel, and Dominic Horsman. "The ZX calculus is a language for surface code lattice surgery." Quantum 4 (January 9, 2020): 218. http://dx.doi.org/10.22331/q-2020-01-09-218.

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A leading choice of error correction for scalable quantum computing is the surface code with lattice surgery. The basic lattice surgery operations, the merging and splitting of logical qubits, act non-unitarily on the logical states and are not easily captured by standard circuit notation. This raises the question of how best to design, verify, and optimise protocols that use lattice surgery, in particular in architectures with complex resource management issues. In this paper we demonstrate that the operations of the ZX calculus --- a form of quantum diagrammatic reasoning based on bialgebras --- match exactly the operations of lattice surgery. Red and green ``spider'' nodes match rough and smooth merges and splits, and follow the axioms of a dagger special associative Frobenius algebra. Some lattice surgery operations require non-trivial correction operations, which are captured natively in the use of the ZX calculus in the form of ensembles of diagrams. We give a first taste of the power of the calculus as a language for lattice surgery by considering two operations (T gates and producing a CNOT) and show how ZX diagram re-write rules give lattice surgery procedures for these operations that are novel, efficient, and highly configurable.

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20

Haar, Taylor Ryan, Yoshifumi Nakamura, and Hinnerk Stüben. "An update on the BQCD Hybrid Monte Carlo program." EPJ Web of Conferences 175 (2018): 14011. http://dx.doi.org/10.1051/epjconf/201817514011.

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We present an update of BQCD, our Hybrid Monte Carlo program for simulating lattice QCD. BQCD is one of the main production codes of the QCDSF collaboration and is used by CSSM and in some Japanese finite temperature and finite density projects. Since the first publication of the code at Lattice 2010 the program has been extended in various ways. New features of the code include: dynamical QED, action modification in order to compute matrix elements by using Feynman-Hellman theory, more trace measurements (like Tr(D-n) for K, cSW and chemical potential reweighting), a more flexible integration scheme, polynomial filtering, term-splitting for RHMC, and a portable implementation of performance critical parts employing SIMD.

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21

Kamiyama, Yohei, Kazuya Yamaji, Hiroki Koike, Daisuke Sato, and Hideki Matsumoto. "ICONE19-43188 Development of a New Lattice Physics Code GALAXY-H for Hexagonal Geometries." Proceedings of the International Conference on Nuclear Engineering (ICONE) 2011.19 (2011): _ICONE1943. http://dx.doi.org/10.1299/jsmeicone.2011.19._icone1943_70.

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22

Taubin, Feliks, and Andrey Trofimov. "Concatenated Coding for Multilevel Flash Memory with Low Error Correction Capabilities in Outer Stage." SPIIRAS Proceedings 18, no. 5 (September 19, 2019): 1149–81. http://dx.doi.org/10.15622/sp.2019.18.5.1149-1181.

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One of the approaches to organization of error correcting coding for multilevel flash memory is based on concatenated construction, in particular, on multidimensional lattices for inner coding. A characteristic feature of such structures is the dominance of the complexity of the outer decoder in the total decoder complexity. Therefore the concatenated construction with low-complexity outer decoder may be attractive since in practical applications the decoder complexity is the crucial limitation for the usage of the error correction coding. We consider a concatenated coding scheme for multilevel flash memory with the Barnes-Wall lattice based codes as an inner code and the Reed-Solomon code with correction up to 4…5 errors as an outer one. Performance analysis is fulfilled for a model characterizing the basic physical features of a flash memory cell with non-uniform target voltage levels and noise variance dependent on the recorded value (input-dependent additive Gaussian noise, ID-AGN). For this model we develop a modification of our approach for evaluation the error probability for the inner code. This modification uses the parallel structure of the inner code trellis which significantly reduces the computational complexity of the performance estimation. We present numerical examples of achievable recording density for the Reed-Solomon codes with correction up to four errors as the outer code for wide range of the retention time and number of write/read cycles.

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23

Harada, Masaaki, and Masaaki Kitazume. "Z4-Code Constructions for the Niemeier Lattices and their Embeddings in the Leech Lattice." European Journal of Combinatorics 21, no. 4 (May 2000): 473–85. http://dx.doi.org/10.1006/eujc.1999.0360.

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24

Ramakrishna, A., V. Jagannathan, and R. P. Jain. "Validation of lattice code ‘EXCEL’ with TIC experiments on uniform and regularly perturbed lattices." Annals of Nuclear Energy 37, no. 12 (December 2010): 1688–98. http://dx.doi.org/10.1016/j.anucene.2010.07.010.

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25

Yoder, Theodore J., and Isaac H. Kim. "The surface code with a twist." Quantum 1 (April 25, 2017): 2. http://dx.doi.org/10.22331/q-2017-04-25-2.

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The surface code is one of the most successful approaches to topological quantum error-correction. It boasts the smallest known syndrome extraction circuits and correspondingly largest thresholds. Defect-based logical encodings of a new variety called twists have made it possible to implement the full Clifford group without state distillation. Here we investigate a patch-based encoding involving a modified twist. In our modified formulation, the resulting codes, called triangle codes for the shape of their planar layout, have only weight-four checks and relatively simple syndrome extraction circuits that maintain a high, near surface-code-level threshold. They also use 25% fewer physical qubits per logical qubit than the surface code. Moreover, benefiting from the twist, we can implement all Clifford gates by lattice surgery without the need for state distillation. By a surgical transformation to the surface code, we also develop a scheme of doing all Clifford gates on surface code patches in an atypical planar layout, though with less qubit efficiency than the triangle code. Finally, we remark that logical qubits encoded in triangle codes are naturally amenable to logical tomography, and the smallest triangle code can demonstrate high-pseudothreshold fault-tolerance to depolarizing noise using just 13 physical qubits.

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Walsh, Stuart D. C., and Martin O. Saar. "Developing Extensible Lattice-Boltzmann Simulators for General-Purpose Graphics-Processing Units." Communications in Computational Physics 13, no. 3 (March 2013): 867–79. http://dx.doi.org/10.4208/cicp.351011.260112s.

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AbstractLattice-Boltzmann methods are versatile numerical modeling techniques capable of reproducing a wide variety of fluid-mechanical behavior. These methods are well suited to parallel implementation, particularly on the single-instruction multiple data (SIMD) parallel processing environments found in computer graphics processing units (GPUs).Although recent programming tools dramatically improve the ease with which GPUbased applications can be written, the programming environment still lacks the flexibility available to more traditional CPU programs. In particular, it may be difficult to develop modular and extensible programs that require variable on-device functionality with current GPU architectures.This paper describes a process of automatic code generation that overcomes these difficulties for lattice-Boltzmann simulations. It details the development of GPU-based modules for an extensible lattice-Boltzmann simulation package – LBHydra. The performance of the automatically generated code is compared to equivalent purposewritten codes for both single-phase,multiphase, andmulticomponent flows. The flexibility of the new method is demonstrated by simulating a rising, dissolving droplet moving through a porous medium with user generated lattice-Boltzmann models and subroutines.

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Seubert, A. "A 3-D FINITE ELEMENT FEW-GROUP DIFFUSION CODE AND ITS APPLICATION TO GENERATION IV REACTOR CONCEPTS." EPJ Web of Conferences 247 (2021): 02010. http://dx.doi.org/10.1051/epjconf/202124702010.

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In this paper, a recently developed 3-d few-group finite element-based diffusion code is de-scribed. Its geometrical flexibility allows future modeling of complex and irregular geometries of (very) small and medium size reactor concepts –(v)SMRs –being in the spotlight for energy provision in remote residential and industrial regions or for space applications, and also liquid metal cooled Generation IV reactors where thermally induced core deformation results in localized assembly lattice distortions which cannot be treated by traditional 3-d neutron kinetics codes devoted to the regular lattices of LWR and Generation IV systems. The description of the implemented FEM solution method is followed by first applications to a prismatic (or block type) high-temperature reactor MHTGR-350MW within an OECD/NEA benchmark activity and to the sodium cooled fast reactor concept ASTRID within the past EU project ESNII+. Finally, an outlook to planned further code development activities is given.

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Desplat, Jean-Christophe, Ignacio Pagonabarraga, and Peter Bladon. "LUDWIG: A parallel Lattice-Boltzmann code for complex fluids." Computer Physics Communications 134, no. 3 (March 2001): 273–90. http://dx.doi.org/10.1016/s0010-4655(00)00205-8.

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29

Barthou, Denis, Olivier Brand-Foissac, Olivier Pène, Gilbert Grosdidier, Romain Dolbeau, Christina Eisenbeis, Michael Kruse, Konstantin Petrov, and Claude Tadonki. "Automated Code Generation for Lattice Quantum Chromodynamics and beyond." Journal of Physics: Conference Series 510 (May 15, 2014): 012005. http://dx.doi.org/10.1088/1742-6596/510/1/012005.

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30

Ueda, S., S. Aoki, T. Aoyama, K. Kanaya, H. Matsufuru, S. Motoki, Y. Namekawa, H. Nemura, Y. Taniguchi, and N. Ukita. "Development of an object oriented lattice QCD code "Bridge++"." Journal of Physics: Conference Series 523 (June 6, 2014): 012046. http://dx.doi.org/10.1088/1742-6596/523/1/012046.

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31

Woodgate, Mark A., George N. Barakos, Rene Steijl, and Gavin J. Pringle. "Parallel performance for a real time Lattice Boltzmann code." Computers & Fluids 173 (September 2018): 237–58. http://dx.doi.org/10.1016/j.compfluid.2018.03.004.

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32

Biferale, Luca, Filippo Mantovani, Marcello Pivanti, Fabio Pozzati, Mauro Sbragaglia, Andrea Scagliarini, Sebastiano Fabio Schifano, Federico Toschi, and Raffaele Tripiccione. "An optimized D2Q37 Lattice Boltzmann code on GP-GPUs." Computers & Fluids 80 (July 2013): 55–62. http://dx.doi.org/10.1016/j.compfluid.2012.06.003.

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33

Wang, Dongyong, Xingjie Peng, Yingrui Yu, Qing Li, and Xiaoming Chai. "Description and verification of KYLIN-V2.0 lattice physics code." Nuclear Engineering and Design 379 (August 2021): 111232. http://dx.doi.org/10.1016/j.nucengdes.2021.111232.

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34

Astrakhantsev, Nikita, Victor Braguta, Andrey Kotov, and Alexander Nikolaev. "Lattice Study of QCD Properties at the “Govorun” Supercomputer." EPJ Web of Conferences 226 (2020): 01002. http://dx.doi.org/10.1051/epjconf/202022601002.

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This report is devoted to Lattice QCD simulations carried out at the “Govorun” supercomputer. The basics of Lattice QCD methodology, the main Lattice QCD algorithms and the most numerically demanding routines are reviewed. We then present details of our multiGPU code implementation and the specifics of its application on the “Govorun” architecture. We show that implementation of very efficient and scalable code is possible and present scalability tests. We finally relate our program with the goals of the NICA project and review the main physical scenarios that are to be studied numerically.

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35

Grabowski, Adam, and Damian Sawicki. "On Two Alternative Axiomatizations of Lattices by McKenzie and Sholander." Formalized Mathematics 26, no. 2 (July 1, 2018): 193–98. http://dx.doi.org/10.2478/forma-2018-0017.

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Summary The main result of the article is to prove formally that two sets of axioms, proposed by McKenzie and Sholander, axiomatize lattices and distributive lattices, respectively. In our Mizar article we used proof objects generated by Prover9. We continue the work started in [7], [21], and [13] of developing lattice theory as initialized in [22] as a formal counterpart of [11]. Complete formal proofs can be found in the Mizar source code of this article available in the Mizar Mathematical Library (MML).

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Matsumine, Toshiki, and Hideki Ochiai. "A Serial Concatenation of Binary-Input Nonbinary-Output Convolutional Code and Recursive Convolutional Lattice Code." IEEE Access 6 (2018): 24809–17. http://dx.doi.org/10.1109/access.2018.2831255.

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YE. TELITCHEV, IGOR, and OLEG VINOGRADOV. "A METHOD FOR QUASI-STATIC ANALYSIS OF TOPOLOGICALLY VARIABLE LATTICE STRUCTURES." International Journal of Computational Methods 03, no. 01 (March 2006): 71–81. http://dx.doi.org/10.1142/s0219876206000813.

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The proposed time-independent quasi-static approach for simulations of lattice structures with imperfections is based on integration of the Inverse Broyden's Method suitable for finding the equilibrium state for a large system of atoms interacting through strongly nonlinear potentials and the Recursive Inverse Matrix Algorithm (RIMA) capable of updating the inverse matrix when topological changes (broken or new bonds between the atoms) take place. In this approach, the crystal structure is treated as a truss system while the forces between the atoms situated at the nodes are defined by the inter-atomic potentials. Since both the Broyden's and the RIMA algorithms deal with the inverse matrices of the structure their coupling makes the procedure computationally efficient. In addition, the method allows analysis of lattices subjected to mixed boundary conditions. The developed code was verified by the comparison with an alternative numerical procedure based on energy minimization technique. The model and the code developed were applied to the case of a 2D hexagonal lattice with the mode I crack embedded into the structure. For the cases considered, it was observed that the crack nucleation and growth were accompanied by the dislocation emission.

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Calore, E., A. Gabbana, SF Schifano, and R. Tripiccione. "Optimization of lattice Boltzmann simulations on heterogeneous computers." International Journal of High Performance Computing Applications 33, no. 1 (April 24, 2017): 124–39. http://dx.doi.org/10.1177/1094342017703771.

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High-performance computing systems are more and more often based on accelerators. Computing applications targeting those systems often follow a host-driven approach, in which hosts offload almost all compute-intensive sections of the code onto accelerators; this approach only marginally exploits the computational resources available on the host CPUs, limiting overall performances. The obvious step forward is to run compute-intensive kernels in a concurrent and balanced way on both hosts and accelerators. In this paper, we consider exactly this problem for a class of applications based on lattice Boltzmann methods, widely used in computational fluid dynamics. Our goal is to develop just one program, portable and able to run efficiently on several different combinations of hosts and accelerators. To reach this goal, we define common data layouts enabling the code to exploit the different parallel and vector options of the various accelerators efficiently, and matching the possibly different requirements of the compute-bound and memory-bound kernels of the application. We also define models and metrics that predict the best partitioning of workloads among host and accelerator, and the optimally achievable overall performance level. We test the performance of our codes and their scaling properties using, as testbeds, HPC clusters incorporating different accelerators: Intel Xeon Phi many-core processors, NVIDIA GPUs, and AMD GPUs.

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Latt, Jonas, Christophe Coreixas, and Joël Beny. "Cross-platform programming model for many-core lattice Boltzmann simulations." PLOS ONE 16, no. 4 (April 29, 2021): e0250306. http://dx.doi.org/10.1371/journal.pone.0250306.

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We present a novel, hardware-agnostic implementation strategy for lattice Boltzmann (LB) simulations, which yields massive performance on homogeneous and heterogeneous many-core platforms. Based solely on C++17 Parallel Algorithms, our approach does not rely on any language extensions, external libraries, vendor-specific code annotations, or pre-compilation steps. Thanks in particular to a recently proposed GPU back-end to C++17 Parallel Algorithms, it is shown that a single code can compile and reach state-of-the-art performance on both many-core CPU and GPU environments for the solution of a given non trivial fluid dynamics problem. The proposed strategy is tested with six different, commonly used implementation schemes to test the performance impact of memory access patterns on different platforms. Nine different LB collision models are included in the tests and exhibit good performance, demonstrating the versatility of our parallel approach. This work shows that it is less than ever necessary to draw a distinction between research and production software, as a concise and generic LB implementation yields performances comparable to those achievable in a hardware specific programming language. The results also highlight the gains of performance achieved by modern many-core CPUs and their apparent capability to narrow the gap with the traditionally massively faster GPU platforms. All code is made available to the community in form of the open-source project stlbm, which serves both as a stand-alone simulation software and as a collection of reusable patterns for the acceleration of pre-existing LB codes.

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40

Hegyi, G., A. Keresztúri, and A. Tóta. "Qualification of the APOLLO2 lattice physics code of the NURISP platform for VVER hexagonal lattices." Kerntechnik 77, no. 4 (August 2012): 218–25. http://dx.doi.org/10.3139/124.110246.

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41

Mora, Peter, Gabriele Morra, and David A. Yuen. "A concise python implementation of the lattice Boltzmann method on HPC for geo-fluid flow." Geophysical Journal International 220, no. 1 (September 26, 2019): 682–702. http://dx.doi.org/10.1093/gji/ggz423.

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SUMMARY The lattice Boltzmann method (LBM) is a method to simulate fluid dynamics based on modelling distributions of particles moving and colliding on a lattice. The Python scripting language provides a clean programming paradigm to develop codes based on the LBM, however in order to reach performance comparable to compiled languages, it needs to be carefully implemented, maximizing its vectorized tools, mostly integrated in the NumPy module. We present here the details of a Python implementation of a concise LBM code, with the purpose of offering a pedagogical tool for students and professionals in the geosciences who are approaching this technique for the first time. The first half of the paper focuses on how to vectorize a 2-D LBM code and show how if carefully done, this allows performance close to a compiled code. In the second part of the paper, we use the vectorization described earlier to naturally write a parallel implementation using MPI and test both weak and hard scaling up to 1280 cores. One benchmark, Poiseuille flow and two applications, one on sound wave propagation and another on fluid-flow through a simplified model of a rock matrix are finally shown.

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Ferraro, Diego, and Eduardo Villarino. "Calculations for a BWR Lattice with Adjacent Gadolinium Pins Using the Monte Carlo Cell Code Serpent v.1.1.7." Science and Technology of Nuclear Installations 2011 (2011): 1–4. http://dx.doi.org/10.1155/2011/659406.

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Monte Carlo neutron transport codes are usually used to perform criticality calculations and to solve shielding problems due to their capability to model complex systems without major approximations. However, these codes demand high computational resources. The improvement in computer capabilities leads to several new applications of Monte Carlo neutron transport codes. An interesting one is to use this method to perform cell-level fuel assembly calculations in order to obtain few group constants to be used on core calculations. In the present work theVTTrecently developedSerpent v.1.1.7cell-oriented neutronic calculation code is used to perform cell calculations of a theoretical BWR lattice benchmark with burnable poisons, and the main results are compared to reported ones and with calculations performed withCondor v.2.61, the INVAP's neutronic collision probability cell code.

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Zhang, Cheng, Liangzhi Cao, Yunzhao Li, and Guowei Hua. "HEXAGONAL PWR-CORE MODELING AND SIMULATION WITH APPLICATION OF NECP-BAMBOO." EPJ Web of Conferences 247 (2021): 06017. http://dx.doi.org/10.1051/epjconf/202124706017.

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In this paper, the modeling and simulation of the PWRs loaded with hexagonal fuel assemblies has been implemented with the NECP-Bamboo code. NECP-Bamboo, consisting of a 2D lattice code named Bamboo-Lattice and a 3D steady-state core code named Bamboo-Core, was primitively designed for the PWRs loaded with the rectangular fuel assemblies. As the capability extension for PWRs with hexagonal fuel assemblies, four aspects of improvement have been implemented in NECP-Bamboo. Firstly, the Constructive Solid Geometry (CSG) has been implemented in Bamboo-Lattice for the lattice modeling. Secondly, the explicit modeling of the reflector assembly has been applied to provide more reliable few-group constants, compared with the conventional 1D model for the reflector assembly. Thirdly, the assembly-homogenization capability has been extended to the hexagonal assembly. Fourthly, the diffusion solver in Bamboo-Core based on the Variational Nodal Method (VNM) has been extended to handle hexagonal geometry. With application of the capability-extended NECP-Bamboo, the modeling and simulations for the VVER-1000 benchmark loaded with MOX fuel has been implemented. It can be observed that the numerical results provided by NECP-Bamboo can agree well with corresponding results by the Monte-Carlo code.

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Kesselring, Markus S., Fernando Pastawski, Jens Eisert, and Benjamin J. Brown. "The boundaries and twist defects of the color code and their applications to topological quantum computation." Quantum 2 (October 19, 2018): 101. http://dx.doi.org/10.22331/q-2018-10-19-101.

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The color code is both an interesting example of an exactly solved topologically ordered phase of matter and also among the most promising candidate models to realize fault-tolerant quantum computation with minimal resource overhead. The contributions of this work are threefold. First of all, we build upon the abstract theory of boundaries and domain walls of topological phases of matter to comprehensively catalog the objects realizable in color codes. Together with our classification we also provide lattice representations of these objects which include three new types of boundaries as well as a generating set for all 72 color code twist defects. Our work thus provides an explicit toy model that will help to better understand the abstract theory of domain walls. Secondly, we discover a number of interesting new applications of the cataloged objects for quantum information protocols. These include improved methods for performing quantum computations by code deformation, a new four-qubit error-detecting code, as well as families of new quantum error-correcting codes we call stellated color codes, which encode logical qubits at the same distance as the next best color code, but using approximately half the number of physical qubits. To the best of our knowledge, our new topological codes have the highest encoding rate of local stabilizer codes with bounded-weight stabilizers in two dimensions. Finally, we show how the boundaries and twist defects of the color code are represented by multiple copies of other phases. Indeed, in addition to the well studied comparison between the color code and two copies of the surface code, we also compare the color code to two copies of the three-fermion model. In particular, we find that this analogy offers a very clear lens through which we can view the symmetries of the color code which gives rise to its multitude of domain walls.

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Hwang, Dae Hee, and Ser Gi Hong. "SMALL MODULAR PWR DESIGN FOR TRU RECYCLING WITH McCARD-MASTER TWO-STEP PROCEDURE." EPJ Web of Conferences 247 (2021): 01003. http://dx.doi.org/10.1051/epjconf/202124701003.

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In our previous study, a small modular PWR core was designed for TRU (Transuranics) recycling with multi-recycling scheme with a typical two-step procedure using DeCART2D/MASTER code system in which the lattice analysis for producing homogenized group constant was performed by DeCART2D while whole core analysis was conducted by MASTER code. However, the neutron spectrum hardening of the LWR core loaded with TRU requires validating the multi-group cross section library and resonance self-shielding treatment method in lattice calculation. In this study, a new procedure using McCARD/MASTER was used to analyze the SMR core, in which the lattice calculation was performed by a Monte Carlo code called McCARD with a continuous energy library to generate homogenized two-group assembly cross sections. The SMR core analysis was performed to show neutronic characteristics and TRU mass flow in the SMR core with TRU multi-recycling. The result shows that the analyses on the neutronic characteristics and TRU mass flow using the McCARD/MASTER code system showed good agreement with the previous ones using the DeCART2D/MASTER code system. The neutronic characteristics of each cycle of the core satisfied the typical limit of a commercial PWR core and the SMR core consumes effectively TRU with net TRU consumption rates of 8.46~14.33 %.

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Azari nazar, Z., M. Abbasi, and M. Zangian. "The PMAXS library generator module based on DRAGON lattice code." Progress in Nuclear Energy 116 (September 2019): 21–27. http://dx.doi.org/10.1016/j.pnucene.2019.03.028.

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Motoki, S., S. Aoki, T. Aoyama, K. Kanaya, H. Matsufuru, Y. Namekawa, H. Nemura, Y. Taniguchi, S. Ueda, and N. Ukita. "Development of Lattice QCD Simulation Code Set “Bridge++” on Accelerators." Procedia Computer Science 29 (2014): 1701–10. http://dx.doi.org/10.1016/j.procs.2014.05.155.

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Aliasgari, Malihe, Daniel Panario, and Mohammad-Reza Sadeghi. "Binomial ideal associated to a lattice and its label code." ACM Communications in Computer Algebra 49, no. 1 (June 10, 2015): 16–17. http://dx.doi.org/10.1145/2768577.2768593.

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Bauer, Martin, Harald Köstler, and Ulrich Rüde. "lbmpy: Automatic code generation for efficient parallel lattice Boltzmann methods." Journal of Computational Science 49 (February 2021): 101269. http://dx.doi.org/10.1016/j.jocs.2020.101269.

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Sainio, J. "PyCOOL — A Cosmological Object-Oriented Lattice code written in Python." Journal of Cosmology and Astroparticle Physics 2012, no. 04 (April 30, 2012): 038. http://dx.doi.org/10.1088/1475-7516/2012/04/038.

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Journal articles on the topic 'Lattice code'

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