---
_id: '10435'
abstract:
- lang: eng
  text: Decentralized optimization is emerging as a viable alternative for scalable
    distributed machine learning, but also introduces new challenges in terms of synchronization
    costs. To this end, several communication-reduction techniques, such as non-blocking
    communication, quantization, and local steps, have been explored in the decentralized
    setting. Due to the complexity of analyzing optimization in such a relaxed setting,
    this line of work often assumes \emph{global} communication rounds, which require
    additional synchronization. In this paper, we consider decentralized optimization
    in the simpler, but harder to analyze, \emph{asynchronous gossip} model, in which
    communication occurs in discrete, randomly chosen pairings among nodes. Perhaps
    surprisingly, we show that a variant of SGD called \emph{SwarmSGD} still converges
    in this setting, even if \emph{non-blocking communication}, \emph{quantization},
    and \emph{local steps} are all applied \emph{in conjunction}, and even if the
    node data distributions and underlying graph topology are both \emph{heterogenous}.
    Our analysis is based on a new connection with multi-dimensional load-balancing
    processes. We implement this algorithm and deploy it in a super-computing environment,
    showing that it can outperform previous decentralized methods in terms of end-to-end
    training time, and that it can even rival carefully-tuned large-batch SGD for
    certain tasks.
acknowledgement: "We gratefully acknowledge funding from the European Research Council
  (ERC) under the European Union’s Horizon 2020 research and innovation programme
  (grant agreement No 805223 ScaleML). PD partly conducted this work while at IST
  Austria and was supported by the European Union’s Horizon 2020 programme under the
  Marie Skłodowska-Curie grant agreement No. 754411. SL was funded in part by European
  Research Council (ERC) under the European Union’s Horizon 2020 programme (grant
  agreement DAPP, No. 678880, and EPiGRAM-HS, No. 801039).\r\n"
article_processing_charge: No
arxiv: 1
author:
- first_name: Giorgi
  full_name: Nadiradze, Giorgi
  id: 3279A00C-F248-11E8-B48F-1D18A9856A87
  last_name: Nadiradze
  orcid: 0000-0001-5634-0731
- first_name: Amirmojtaba
  full_name: Sabour, Amirmojtaba
  id: bcc145fd-e77f-11ea-ae8b-80d661dbff67
  last_name: Sabour
- first_name: Peter
  full_name: Davies, Peter
  id: 11396234-BB50-11E9-B24C-90FCE5697425
  last_name: Davies
  orcid: 0000-0002-5646-9524
- first_name: Shigang
  full_name: Li, Shigang
  last_name: Li
- first_name: Dan-Adrian
  full_name: Alistarh, Dan-Adrian
  id: 4A899BFC-F248-11E8-B48F-1D18A9856A87
  last_name: Alistarh
  orcid: 0000-0003-3650-940X
citation:
  ama: 'Nadiradze G, Sabour A, Davies P, Li S, Alistarh D-A. Asynchronous decentralized
    SGD with quantized and local updates. In: <i>35th Conference on Neural Information
    Processing Systems</i>. Neural Information Processing Systems Foundation; 2021.'
  apa: 'Nadiradze, G., Sabour, A., Davies, P., Li, S., &#38; Alistarh, D.-A. (2021).
    Asynchronous decentralized SGD with quantized and local updates. In <i>35th Conference
    on Neural Information Processing Systems</i>. Sydney, Australia: Neural Information
    Processing Systems Foundation.'
  chicago: Nadiradze, Giorgi, Amirmojtaba Sabour, Peter Davies, Shigang Li, and Dan-Adrian
    Alistarh. “Asynchronous Decentralized SGD with Quantized and Local Updates.” In
    <i>35th Conference on Neural Information Processing Systems</i>. Neural Information
    Processing Systems Foundation, 2021.
  ieee: G. Nadiradze, A. Sabour, P. Davies, S. Li, and D.-A. Alistarh, “Asynchronous
    decentralized SGD with quantized and local updates,” in <i>35th Conference on
    Neural Information Processing Systems</i>, Sydney, Australia, 2021.
  ista: 'Nadiradze G, Sabour A, Davies P, Li S, Alistarh D-A. 2021. Asynchronous decentralized
    SGD with quantized and local updates. 35th Conference on Neural Information Processing
    Systems. NeurIPS: Neural Information Processing Systems.'
  mla: Nadiradze, Giorgi, et al. “Asynchronous Decentralized SGD with Quantized and
    Local Updates.” <i>35th Conference on Neural Information Processing Systems</i>,
    Neural Information Processing Systems Foundation, 2021.
  short: G. Nadiradze, A. Sabour, P. Davies, S. Li, D.-A. Alistarh, in:, 35th Conference
    on Neural Information Processing Systems, Neural Information Processing Systems
    Foundation, 2021.
conference:
  end_date: 2021-12-14
  location: Sydney, Australia
  name: 'NeurIPS: Neural Information Processing Systems'
  start_date: 2021-12-06
date_created: 2021-12-09T10:59:12Z
date_published: 2021-12-01T00:00:00Z
date_updated: 2023-10-17T11:48:56Z
day: '01'
department:
- _id: DaAl
ec_funded: 1
external_id:
  arxiv:
  - '1910.12308'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://papers.nips.cc/paper/2021/hash/362c99307cdc3f2d8b410652386a9dd1-Abstract.html
month: '12'
oa: 1
oa_version: Published Version
project:
- _id: 260C2330-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '754411'
  name: ISTplus - Postdoctoral Fellowships
- _id: 268A44D6-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '805223'
  name: Elastic Coordination for Scalable Machine Learning
publication: 35th Conference on Neural Information Processing Systems
publication_status: published
publisher: Neural Information Processing Systems Foundation
quality_controlled: '1'
related_material:
  record:
  - id: '10429'
    relation: dissertation_contains
    status: public
status: public
title: Asynchronous decentralized SGD with quantized and local updates
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2021'
...
---
_id: '11452'
abstract:
- lang: eng
  text: We study efficient distributed algorithms for the fundamental problem of principal
    component analysis and leading eigenvector computation on the sphere, when the
    data are randomly distributed among a set of computational nodes. We propose a
    new quantized variant of Riemannian gradient descent to solve this problem, and
    prove that the algorithm converges with high probability under a set of necessary
    spherical-convexity properties. We give bounds on the number of bits transmitted
    by the algorithm under common initialization schemes, and investigate the dependency
    on the problem dimension in each case.
acknowledgement: We would like to thank the anonymous reviewers for helpful comments
  and suggestions. We also thank Aurelien Lucchi and Antonio Orvieto for fruitful
  discussions at an early stage of this work. FA is partially supported by the SNSF
  under research project No. 192363 and conducted part of this work while at IST Austria
  under the European Union’s Horizon 2020 research and innovation programme (grant
  agreement No. 805223 ScaleML). PD partly conducted this work while at IST Austria
  and was supported by the European Union’s Horizon 2020 programme under the Marie
  Skłodowska-Curie grant agreement No. 754411.
article_processing_charge: No
arxiv: 1
author:
- first_name: Foivos
  full_name: Alimisis, Foivos
  last_name: Alimisis
- first_name: Peter
  full_name: Davies, Peter
  id: 11396234-BB50-11E9-B24C-90FCE5697425
  last_name: Davies
  orcid: 0000-0002-5646-9524
- first_name: Bart
  full_name: Vandereycken, Bart
  last_name: Vandereycken
- first_name: Dan-Adrian
  full_name: Alistarh, Dan-Adrian
  id: 4A899BFC-F248-11E8-B48F-1D18A9856A87
  last_name: Alistarh
  orcid: 0000-0003-3650-940X
citation:
  ama: 'Alimisis F, Davies P, Vandereycken B, Alistarh D-A. Distributed principal
    component analysis with limited communication. In: <i>Advances in Neural Information
    Processing Systems - 35th Conference on Neural Information Processing Systems</i>.
    Vol 4. Neural Information Processing Systems Foundation; 2021:2823-2834.'
  apa: 'Alimisis, F., Davies, P., Vandereycken, B., &#38; Alistarh, D.-A. (2021).
    Distributed principal component analysis with limited communication. In <i>Advances
    in Neural Information Processing Systems - 35th Conference on Neural Information
    Processing Systems</i> (Vol. 4, pp. 2823–2834). Virtual, Online: Neural Information
    Processing Systems Foundation.'
  chicago: Alimisis, Foivos, Peter Davies, Bart Vandereycken, and Dan-Adrian Alistarh.
    “Distributed Principal Component Analysis with Limited Communication.” In <i>Advances
    in Neural Information Processing Systems - 35th Conference on Neural Information
    Processing Systems</i>, 4:2823–34. Neural Information Processing Systems Foundation,
    2021.
  ieee: F. Alimisis, P. Davies, B. Vandereycken, and D.-A. Alistarh, “Distributed
    principal component analysis with limited communication,” in <i>Advances in Neural
    Information Processing Systems - 35th Conference on Neural Information Processing
    Systems</i>, Virtual, Online, 2021, vol. 4, pp. 2823–2834.
  ista: 'Alimisis F, Davies P, Vandereycken B, Alistarh D-A. 2021. Distributed principal
    component analysis with limited communication. Advances in Neural Information
    Processing Systems - 35th Conference on Neural Information Processing Systems.
    NeurIPS: Neural Information Processing Systems vol. 4, 2823–2834.'
  mla: Alimisis, Foivos, et al. “Distributed Principal Component Analysis with Limited
    Communication.” <i>Advances in Neural Information Processing Systems - 35th Conference
    on Neural Information Processing Systems</i>, vol. 4, Neural Information Processing
    Systems Foundation, 2021, pp. 2823–34.
  short: F. Alimisis, P. Davies, B. Vandereycken, D.-A. Alistarh, in:, Advances in
    Neural Information Processing Systems - 35th Conference on Neural Information
    Processing Systems, Neural Information Processing Systems Foundation, 2021, pp.
    2823–2834.
conference:
  end_date: 2021-12-14
  location: Virtual, Online
  name: 'NeurIPS: Neural Information Processing Systems'
  start_date: 2021-12-06
date_created: 2022-06-19T22:01:58Z
date_published: 2021-12-01T00:00:00Z
date_updated: 2022-06-20T08:31:52Z
day: '01'
department:
- _id: DaAl
ec_funded: 1
external_id:
  arxiv:
  - '2110.14391'
intvolume: '         4'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://proceedings.neurips.cc/paper/2021/file/1680e9fa7b4dd5d62ece800239bb53bd-Paper.pdf
month: '12'
oa: 1
oa_version: Published Version
page: 2823-2834
project:
- _id: 268A44D6-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '805223'
  name: Elastic Coordination for Scalable Machine Learning
- _id: 260C2330-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '754411'
  name: ISTplus - Postdoctoral Fellowships
publication: Advances in Neural Information Processing Systems - 35th Conference on
  Neural Information Processing Systems
publication_identifier:
  isbn:
  - '9781713845393'
  issn:
  - 1049-5258
publication_status: published
publisher: Neural Information Processing Systems Foundation
quality_controlled: '1'
scopus_import: '1'
status: public
title: Distributed principal component analysis with limited communication
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 4
year: '2021'
...
---
_id: '13147'
abstract:
- lang: eng
  text: "We investigate fast and communication-efficient algorithms for the classic
    problem of minimizing a sum of strongly convex and smooth functions that are distributed
    among n\r\n different nodes, which can communicate using a limited number of bits.
    Most previous communication-efficient approaches for this problem are limited
    to first-order optimization, and therefore have \\emph{linear} dependence on the
    condition number in their communication complexity. We show that this dependence
    is not inherent: communication-efficient methods can in fact have sublinear dependence
    on the condition number. For this, we design and analyze the first communication-efficient
    distributed variants of preconditioned gradient descent for Generalized Linear
    Models, and for Newton’s method. Our results rely on a new technique for quantizing
    both the preconditioner and the descent direction at each step of the algorithms,
    while controlling their convergence rate. We also validate our findings experimentally,
    showing faster convergence and reduced communication relative to previous methods."
acknowledgement: The authors would like to thank Janne Korhonen, Aurelien Lucchi,
  Celestine MendlerDunner and Antonio Orvieto for helpful discussions. FA ¨and DA
  were supported during this work by the European Research Council (ERC) under the
  European Union’s Horizon 2020 research and innovation programme (grant agreement
  No 805223 ScaleML). PD was supported by the European Union’s Horizon 2020 programme
  under the Marie Skłodowska-Curie grant agreement No. 754411.
article_processing_charge: No
arxiv: 1
author:
- first_name: Foivos
  full_name: Alimisis, Foivos
  last_name: Alimisis
- first_name: Peter
  full_name: Davies, Peter
  id: 11396234-BB50-11E9-B24C-90FCE5697425
  last_name: Davies
  orcid: 0000-0002-5646-9524
- first_name: Dan-Adrian
  full_name: Alistarh, Dan-Adrian
  id: 4A899BFC-F248-11E8-B48F-1D18A9856A87
  last_name: Alistarh
  orcid: 0000-0003-3650-940X
citation:
  ama: 'Alimisis F, Davies P, Alistarh D-A. Communication-efficient distributed optimization
    with quantized preconditioners. In: <i>Proceedings of the 38th International Conference
    on Machine Learning</i>. Vol 139. ML Research Press; 2021:196-206.'
  apa: 'Alimisis, F., Davies, P., &#38; Alistarh, D.-A. (2021). Communication-efficient
    distributed optimization with quantized preconditioners. In <i>Proceedings of
    the 38th International Conference on Machine Learning</i> (Vol. 139, pp. 196–206).
    Virtual: ML Research Press.'
  chicago: Alimisis, Foivos, Peter Davies, and Dan-Adrian Alistarh. “Communication-Efficient
    Distributed Optimization with Quantized Preconditioners.” In <i>Proceedings of
    the 38th International Conference on Machine Learning</i>, 139:196–206. ML Research
    Press, 2021.
  ieee: F. Alimisis, P. Davies, and D.-A. Alistarh, “Communication-efficient distributed
    optimization with quantized preconditioners,” in <i>Proceedings of the 38th International
    Conference on Machine Learning</i>, Virtual, 2021, vol. 139, pp. 196–206.
  ista: Alimisis F, Davies P, Alistarh D-A. 2021. Communication-efficient distributed
    optimization with quantized preconditioners. Proceedings of the 38th International
    Conference on Machine Learning. International Conference on Machine Learning vol.
    139, 196–206.
  mla: Alimisis, Foivos, et al. “Communication-Efficient Distributed Optimization
    with Quantized Preconditioners.” <i>Proceedings of the 38th International Conference
    on Machine Learning</i>, vol. 139, ML Research Press, 2021, pp. 196–206.
  short: F. Alimisis, P. Davies, D.-A. Alistarh, in:, Proceedings of the 38th International
    Conference on Machine Learning, ML Research Press, 2021, pp. 196–206.
conference:
  end_date: 2021-07-24
  location: Virtual
  name: International Conference on Machine Learning
  start_date: 2021-07-18
date_created: 2023-06-18T22:00:48Z
date_published: 2021-07-01T00:00:00Z
date_updated: 2023-06-19T10:44:38Z
day: '01'
ddc:
- '000'
department:
- _id: DaAl
ec_funded: 1
external_id:
  arxiv:
  - '2102.07214'
file:
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  checksum: 7ec0d59bac268b49c76bf2e036dedd7a
  content_type: application/pdf
  creator: dernst
  date_created: 2023-06-19T10:41:05Z
  date_updated: 2023-06-19T10:41:05Z
  file_id: '13154'
  file_name: 2021_PMLR_Alimisis.pdf
  file_size: 429087
  relation: main_file
  success: 1
file_date_updated: 2023-06-19T10:41:05Z
has_accepted_license: '1'
intvolume: '       139'
language:
- iso: eng
license: https://creativecommons.org/licenses/by/4.0/
month: '07'
oa: 1
oa_version: Published Version
page: 196-206
project:
- _id: 268A44D6-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '805223'
  name: Elastic Coordination for Scalable Machine Learning
- _id: 260C2330-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '754411'
  name: ISTplus - Postdoctoral Fellowships
publication: Proceedings of the 38th International Conference on Machine Learning
publication_identifier:
  eissn:
  - 2640-3498
  isbn:
  - '9781713845065'
publication_status: published
publisher: ML Research Press
quality_controlled: '1'
scopus_import: '1'
status: public
title: Communication-efficient distributed optimization with quantized preconditioners
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 139
year: '2021'
...
---
_id: '9541'
abstract:
- lang: eng
  text: The Massively Parallel Computation (MPC) model is an emerging model that distills
    core aspects of distributed and parallel computation, developed as a tool to solve
    combinatorial (typically graph) problems in systems of many machines with limited
    space. Recent work has focused on the regime in which machines have sublinear
    (in n, the number of nodes in the input graph) space, with randomized algorithms
    presented for the fundamental problems of Maximal Matching and Maximal Independent
    Set. However, there have been no prior corresponding deterministic algorithms.
    A major challenge underlying the sublinear space setting is that the local space
    of each machine might be too small to store all edges incident to a single node.
    This poses a considerable obstacle compared to classical models in which each
    node is assumed to know and have easy access to its incident edges. To overcome
    this barrier, we introduce a new graph sparsification technique that deterministically
    computes a low-degree subgraph, with the additional property that solving the
    problem on this subgraph provides significant progress towards solving the problem
    for the original input graph. Using this framework to derandomize the well-known
    algorithm of Luby [SICOMP’86], we obtain O(log Δ + log log n)-round deterministic
    MPC algorithms for solving the problems of Maximal Matching and Maximal Independent
    Set with O(nɛ) space on each machine for any constant ɛ > 0. These algorithms
    also run in O(log Δ) rounds in the closely related model of CONGESTED CLIQUE,
    improving upon the state-of-the-art bound of O(log 2Δ) rounds by Censor-Hillel
    et al. [DISC’17].
acknowledgement: "Institute of Science and Technology Austria (IST Austria). Email:
  peter.davies@ist.ac.at. Work partially\r\ndone at the Department of Computer Science
  and Centre for Discrete Mathematics and its Applications (DIMAP),University of Warwick.
  Research partially supported by the European Union’s Horizon 2020 research and innovation
  programme under the Marie Skłodowska-Curie grant agreement No 754411, the Centre
  for Discrete Mathematics and its Applications, a Weizmann-UK Making Connections
  Grant, and EPSRC award EP/N011163/1."
article_number: '16'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Artur
  full_name: Czumaj, Artur
  last_name: Czumaj
- first_name: Peter
  full_name: Davies, Peter
  id: 11396234-BB50-11E9-B24C-90FCE5697425
  last_name: Davies
  orcid: 0000-0002-5646-9524
- first_name: Merav
  full_name: Parter, Merav
  last_name: Parter
citation:
  ama: Czumaj A, Davies P, Parter M. Graph sparsification for derandomizing massively
    parallel computation with low space. <i>ACM Transactions on Algorithms</i>. 2021;17(2).
    doi:<a href="https://doi.org/10.1145/3451992">10.1145/3451992</a>
  apa: Czumaj, A., Davies, P., &#38; Parter, M. (2021). Graph sparsification for derandomizing
    massively parallel computation with low space. <i>ACM Transactions on Algorithms</i>.
    Association for Computing Machinery. <a href="https://doi.org/10.1145/3451992">https://doi.org/10.1145/3451992</a>
  chicago: Czumaj, Artur, Peter Davies, and Merav Parter. “Graph Sparsification for
    Derandomizing Massively Parallel Computation with Low Space.” <i>ACM Transactions
    on Algorithms</i>. Association for Computing Machinery, 2021. <a href="https://doi.org/10.1145/3451992">https://doi.org/10.1145/3451992</a>.
  ieee: A. Czumaj, P. Davies, and M. Parter, “Graph sparsification for derandomizing
    massively parallel computation with low space,” <i>ACM Transactions on Algorithms</i>,
    vol. 17, no. 2. Association for Computing Machinery, 2021.
  ista: Czumaj A, Davies P, Parter M. 2021. Graph sparsification for derandomizing
    massively parallel computation with low space. ACM Transactions on Algorithms.
    17(2), 16.
  mla: Czumaj, Artur, et al. “Graph Sparsification for Derandomizing Massively Parallel
    Computation with Low Space.” <i>ACM Transactions on Algorithms</i>, vol. 17, no.
    2, 16, Association for Computing Machinery, 2021, doi:<a href="https://doi.org/10.1145/3451992">10.1145/3451992</a>.
  short: A. Czumaj, P. Davies, M. Parter, ACM Transactions on Algorithms 17 (2021).
date_created: 2021-06-10T19:31:05Z
date_published: 2021-06-01T00:00:00Z
date_updated: 2024-02-28T12:53:09Z
day: '01'
ddc:
- '000'
department:
- _id: DaAl
doi: 10.1145/3451992
ec_funded: 1
external_id:
  arxiv:
  - '1912.05390'
  isi:
  - '000661311300006'
file:
- access_level: open_access
  checksum: a21c627683890c309a68f6389302c408
  content_type: application/pdf
  creator: pdavies
  date_created: 2021-06-10T19:33:56Z
  date_updated: 2021-06-10T19:33:56Z
  file_id: '9542'
  file_name: MISMM-arxiv.pdf
  file_size: 587404
  relation: main_file
  success: 1
file_date_updated: 2021-06-10T19:33:56Z
has_accepted_license: '1'
intvolume: '        17'
isi: 1
issue: '2'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/1912.05390
month: '06'
oa: 1
oa_version: Submitted Version
project:
- _id: 260C2330-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '754411'
  name: ISTplus - Postdoctoral Fellowships
publication: ACM Transactions on Algorithms
publication_identifier:
  eissn:
  - 1549-6333
  issn:
  - 1549-6325
publication_status: published
publisher: Association for Computing Machinery
quality_controlled: '1'
related_material:
  record:
  - id: '7802'
    relation: earlier_version
    status: public
status: public
title: Graph sparsification for derandomizing massively parallel computation with
  low space
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 17
year: '2021'
...
---
_id: '9543'
abstract:
- lang: eng
  text: We consider the problem ofdistributed mean estimation (DME), in which n machines
    are each given a local d-dimensional vector xv∈Rd, and must cooperate to estimate
    the mean of their inputs μ=1n∑nv=1xv, while minimizing total communication cost.
    DME is a fundamental construct in distributed machine learning, and there has
    been considerable work on variants of this problem, especially in the context
    of distributed variance reduction for stochastic gradients in parallel SGD. Previous
    work typically assumes an upper bound on the norm of the input vectors, and achieves
    an error bound in terms of this norm. However, in many real applications, the
    input vectors are concentrated around the correct output μ, but μ itself has large
    norm. In such cases, previous output error bounds perform poorly. In this paper,
    we show that output error bounds need not depend on input norm. We provide a method
    of quantization which allows distributed mean estimation to be performed with
    solution quality dependent only on the distance between inputs, not on input norm,
    and show an analogous result for distributed variance reduction. The technique
    is based on a new connection with lattice theory. We also provide lower bounds
    showing that the communication to error trade-off of our algorithms is asymptotically
    optimal. As the lattices achieving optimal bounds under l2-norm can be computationally
    impractical, we also present an extension which leverages easy-to-use cubic lattices,
    and is loose only up to a logarithmic factor ind. We show experimentally that
    our method yields practical improvements for common applications, relative to
    prior approaches.
article_processing_charge: No
arxiv: 1
author:
- first_name: Peter
  full_name: Davies, Peter
  id: 11396234-BB50-11E9-B24C-90FCE5697425
  last_name: Davies
  orcid: 0000-0002-5646-9524
- first_name: Vijaykrishna
  full_name: Gurunanthan, Vijaykrishna
  last_name: Gurunanthan
- first_name: 'Niusha '
  full_name: 'Moshrefi, Niusha '
  id: 4db776ff-ce15-11eb-96e3-bc2b90b01c16
  last_name: Moshrefi
- first_name: Saleh
  full_name: Ashkboos, Saleh
  id: 0D0A9058-257B-11EA-A937-9341C3D8BC8A
  last_name: Ashkboos
- first_name: Dan-Adrian
  full_name: Alistarh, Dan-Adrian
  id: 4A899BFC-F248-11E8-B48F-1D18A9856A87
  last_name: Alistarh
  orcid: 0000-0003-3650-940X
citation:
  ama: 'Davies P, Gurunanthan V, Moshrefi N, Ashkboos S, Alistarh D-A. New bounds
    for distributed mean estimation and variance reduction. In: <i>9th International
    Conference on Learning Representations</i>. ; 2021.'
  apa: Davies, P., Gurunanthan, V., Moshrefi, N., Ashkboos, S., &#38; Alistarh, D.-A.
    (2021). New bounds for distributed mean estimation and variance reduction. In
    <i>9th International Conference on Learning Representations</i>. Virtual.
  chicago: Davies, Peter, Vijaykrishna Gurunanthan, Niusha  Moshrefi, Saleh Ashkboos,
    and Dan-Adrian Alistarh. “New Bounds for Distributed Mean Estimation and Variance
    Reduction.” In <i>9th International Conference on Learning Representations</i>,
    2021.
  ieee: P. Davies, V. Gurunanthan, N. Moshrefi, S. Ashkboos, and D.-A. Alistarh, “New
    bounds for distributed mean estimation and variance reduction,” in <i>9th International
    Conference on Learning Representations</i>, Virtual, 2021.
  ista: 'Davies P, Gurunanthan V, Moshrefi N, Ashkboos S, Alistarh D-A. 2021. New
    bounds for distributed mean estimation and variance reduction. 9th International
    Conference on Learning Representations.  ICLR: International Conference on Learning
    Representations.'
  mla: Davies, Peter, et al. “New Bounds for Distributed Mean Estimation and Variance
    Reduction.” <i>9th International Conference on Learning Representations</i>, 2021.
  short: P. Davies, V. Gurunanthan, N. Moshrefi, S. Ashkboos, D.-A. Alistarh, in:,
    9th International Conference on Learning Representations, 2021.
conference:
  end_date: 2021-05-07
  location: Virtual
  name: ' ICLR: International Conference on Learning Representations'
  start_date: 2021-05-03
date_created: 2021-06-10T19:46:08Z
date_published: 2021-05-01T00:00:00Z
date_updated: 2023-02-23T14:00:40Z
day: '01'
department:
- _id: DaAl
ec_funded: 1
external_id:
  arxiv:
  - '2002.09268'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://openreview.net/pdf?id=t86MwoUCCNe
month: '05'
oa: 1
oa_version: Published Version
project:
- _id: 260C2330-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '754411'
  name: ISTplus - Postdoctoral Fellowships
publication: 9th International Conference on Learning Representations
publication_status: published
quality_controlled: '1'
status: public
title: New bounds for distributed mean estimation and variance reduction
type: conference
user_id: D865714E-FA4E-11E9-B85B-F5C5E5697425
year: '2021'
...
---
_id: '9620'
abstract:
- lang: eng
  text: "In this note, we introduce a distributed twist on the classic coupon collector
    problem: a set of m collectors wish to each obtain a set of n coupons; for this,
    they can each sample coupons uniformly at random, but can also meet in pairwise
    interactions, during which they can exchange coupons. By doing so, they hope to
    reduce the number of coupons that must be sampled by each collector in order to
    obtain a full set. This extension is natural when considering real-world manifestations
    of the coupon collector phenomenon, and has been remarked upon and studied empirically
    (Hayes and Hannigan 2006, Ahmad et al. 2014, Delmarcelle 2019).\r\n\r\nWe provide
    the first theoretical analysis for such a scenario. We find that “coupon collecting
    with friends” can indeed significantly reduce the number of coupons each collector
    must sample, and raises interesting connections to the more traditional variants
    of the problem. While our analysis is in most cases asymptotically tight, there
    are several open questions raised, regarding finer-grained analysis of both “coupon
    collecting with friends,” and of a long-studied variant of the original problem
    in which a collector requires multiple full sets of coupons."
acknowledgement: Peter Davies is supported by the European Union’s Horizon2020 research
  and innovation programme under the Marie Skłodowska-Curie grant agreement No. 754411.
alternative_title:
- LNCS
article_processing_charge: No
author:
- first_name: Dan-Adrian
  full_name: Alistarh, Dan-Adrian
  id: 4A899BFC-F248-11E8-B48F-1D18A9856A87
  last_name: Alistarh
  orcid: 0000-0003-3650-940X
- first_name: Peter
  full_name: Davies, Peter
  id: 11396234-BB50-11E9-B24C-90FCE5697425
  last_name: Davies
  orcid: 0000-0002-5646-9524
citation:
  ama: 'Alistarh D-A, Davies P. Collecting coupons is faster with friends. In: <i>Structural
    Information and Communication Complexity</i>. Vol 12810. Springer Nature; 2021:3-12.
    doi:<a href="https://doi.org/10.1007/978-3-030-79527-6_1">10.1007/978-3-030-79527-6_1</a>'
  apa: 'Alistarh, D.-A., &#38; Davies, P. (2021). Collecting coupons is faster with
    friends. In <i>Structural Information and Communication Complexity</i> (Vol. 12810,
    pp. 3–12). Wrocław, Poland: Springer Nature. <a href="https://doi.org/10.1007/978-3-030-79527-6_1">https://doi.org/10.1007/978-3-030-79527-6_1</a>'
  chicago: Alistarh, Dan-Adrian, and Peter Davies. “Collecting Coupons Is Faster with
    Friends.” In <i>Structural Information and Communication Complexity</i>, 12810:3–12.
    Springer Nature, 2021. <a href="https://doi.org/10.1007/978-3-030-79527-6_1">https://doi.org/10.1007/978-3-030-79527-6_1</a>.
  ieee: D.-A. Alistarh and P. Davies, “Collecting coupons is faster with friends,”
    in <i>Structural Information and Communication Complexity</i>, Wrocław, Poland,
    2021, vol. 12810, pp. 3–12.
  ista: 'Alistarh D-A, Davies P. 2021. Collecting coupons is faster with friends.
    Structural Information and Communication Complexity.  SIROCCO: International Colloquium
    on Structural Information and Communication Complexity, LNCS, vol. 12810, 3–12.'
  mla: Alistarh, Dan-Adrian, and Peter Davies. “Collecting Coupons Is Faster with
    Friends.” <i>Structural Information and Communication Complexity</i>, vol. 12810,
    Springer Nature, 2021, pp. 3–12, doi:<a href="https://doi.org/10.1007/978-3-030-79527-6_1">10.1007/978-3-030-79527-6_1</a>.
  short: D.-A. Alistarh, P. Davies, in:, Structural Information and Communication
    Complexity, Springer Nature, 2021, pp. 3–12.
conference:
  end_date: 2021-07-01
  location: Wrocław, Poland
  name: ' SIROCCO: International Colloquium on Structural Information and Communication
    Complexity'
  start_date: 2021-06-28
date_created: 2021-07-01T11:04:43Z
date_published: 2021-06-20T00:00:00Z
date_updated: 2023-02-23T14:02:46Z
day: '20'
ddc:
- '000'
department:
- _id: DaAl
doi: 10.1007/978-3-030-79527-6_1
ec_funded: 1
file:
- access_level: open_access
  checksum: fe37fb9af3f5016c1084af9d6e7109bd
  content_type: application/pdf
  creator: pdavies
  date_created: 2021-07-01T11:21:40Z
  date_updated: 2021-07-01T11:21:40Z
  file_id: '9621'
  file_name: Population_Coupon_Collector.pdf
  file_size: 319728
  relation: main_file
file_date_updated: 2021-07-01T11:21:40Z
has_accepted_license: '1'
intvolume: '     12810'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Preprint
page: 3-12
project:
- _id: 260C2330-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '754411'
  name: ISTplus - Postdoctoral Fellowships
publication: Structural Information and Communication Complexity
publication_identifier:
  eisbn:
  - '9783030795276'
  eissn:
  - 1611-3349
  isbn:
  - '9783030795269'
  issn:
  - 0302-9743
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
status: public
title: Collecting coupons is faster with friends
type: conference
user_id: D865714E-FA4E-11E9-B85B-F5C5E5697425
volume: 12810
year: '2021'
...
---
_id: '9933'
abstract:
- lang: eng
  text: "In this paper, we study the power and limitations of component-stable algorithms
    in the low-space model of Massively Parallel Computation (MPC). Recently Ghaffari,
    Kuhn and Uitto (FOCS 2019) introduced the class of component-stable low-space
    MPC algorithms, which are, informally, defined as algorithms for which the outputs
    reported by the nodes in different connected components are required to be independent.
    This very natural notion was introduced to capture most (if not all) of the known
    efficient MPC algorithms to date, and it was the first general class of MPC algorithms
    for which one can show non-trivial conditional lower bounds. In this paper we
    enhance the framework of component-stable algorithms and investigate its effect
    on the complexity of randomized and deterministic low-space MPC. Our key contributions
    include: 1) We revise and formalize the lifting approach of Ghaffari, Kuhn and
    Uitto. This requires a very delicate amendment of the notion of component stability,
    which allows us to fill in gaps in the earlier arguments. 2) We also extend the
    framework to obtain conditional lower bounds for deterministic algorithms and
    fine-grained lower bounds that depend on the maximum degree Δ. 3) We demonstrate
    a collection of natural graph problems for which non-component-stable algorithms
    break the conditional lower bound obtained for component-stable algorithms. This
    implies that, for both deterministic and randomized algorithms, component-stable
    algorithms are conditionally weaker than the non-component-stable ones.\r\n\r\nAltogether
    our results imply that component-stability might limit the computational power
    of the low-space MPC model, paving the way for improved upper bounds that escape
    the conditional lower bound setting of Ghaffari, Kuhn, and Uitto."
acknowledgement: This work is partially supported by a Weizmann-UK Making Connections
  Grant, the Centre for Discrete Mathematics and its Applications (DIMAP), IBM Faculty
  Award, EPSRC award EP/V01305X/1, European Research Council (ERC) Grant No. 949083,
  the Minerva foundation with funding from the Federal German Ministry for Education
  and Research No. 713238, and the European Union’s Horizon 2020 programme under the
  Marie Skłodowska-Curie grant agreement No 754411.
article_processing_charge: No
arxiv: 1
author:
- first_name: Artur
  full_name: Czumaj, Artur
  last_name: Czumaj
- first_name: Peter
  full_name: Davies, Peter
  id: 11396234-BB50-11E9-B24C-90FCE5697425
  last_name: Davies
  orcid: 0000-0002-5646-9524
- first_name: Merav
  full_name: Parter, Merav
  last_name: Parter
citation:
  ama: 'Czumaj A, Davies P, Parter M. Component stability in low-space massively parallel
    computation. In: <i>Proceedings of the 2021 ACM Symposium on Principles of Distributed
    Computing</i>. Association for Computing Machinery; 2021:481–491. doi:<a href="https://doi.org/10.1145/3465084.3467903">10.1145/3465084.3467903</a>'
  apa: 'Czumaj, A., Davies, P., &#38; Parter, M. (2021). Component stability in low-space
    massively parallel computation. In <i>Proceedings of the 2021 ACM Symposium on
    Principles of Distributed Computing</i> (pp. 481–491). Virtual, Italy: Association
    for Computing Machinery. <a href="https://doi.org/10.1145/3465084.3467903">https://doi.org/10.1145/3465084.3467903</a>'
  chicago: Czumaj, Artur, Peter Davies, and Merav Parter. “Component Stability in
    Low-Space Massively Parallel Computation.” In <i>Proceedings of the 2021 ACM Symposium
    on Principles of Distributed Computing</i>, 481–491. Association for Computing
    Machinery, 2021. <a href="https://doi.org/10.1145/3465084.3467903">https://doi.org/10.1145/3465084.3467903</a>.
  ieee: A. Czumaj, P. Davies, and M. Parter, “Component stability in low-space massively
    parallel computation,” in <i>Proceedings of the 2021 ACM Symposium on Principles
    of Distributed Computing</i>, Virtual, Italy, 2021, pp. 481–491.
  ista: 'Czumaj A, Davies P, Parter M. 2021. Component stability in low-space massively
    parallel computation. Proceedings of the 2021 ACM Symposium on Principles of Distributed
    Computing. PODC: Principles of Distributed Computing, 481–491.'
  mla: Czumaj, Artur, et al. “Component Stability in Low-Space Massively Parallel
    Computation.” <i>Proceedings of the 2021 ACM Symposium on Principles of Distributed
    Computing</i>, Association for Computing Machinery, 2021, pp. 481–491, doi:<a
    href="https://doi.org/10.1145/3465084.3467903">10.1145/3465084.3467903</a>.
  short: A. Czumaj, P. Davies, M. Parter, in:, Proceedings of the 2021 ACM Symposium
    on Principles of Distributed Computing, Association for Computing Machinery, 2021,
    pp. 481–491.
conference:
  end_date: 2021-07-30
  location: Virtual, Italy
  name: 'PODC: Principles of Distributed Computing'
  start_date: 2021-07-26
date_created: 2021-08-17T18:11:16Z
date_published: 2021-07-21T00:00:00Z
date_updated: 2023-08-17T07:11:32Z
day: '21'
department:
- _id: DaAl
doi: 10.1145/3465084.3467903
ec_funded: 1
external_id:
  arxiv:
  - '2106.01880'
  isi:
  - '000744439800049'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2106.01880
month: '07'
oa: 1
oa_version: Submitted Version
page: 481–491
project:
- _id: 260C2330-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '754411'
  name: ISTplus - Postdoctoral Fellowships
publication: Proceedings of the 2021 ACM Symposium on Principles of Distributed Computing
publication_identifier:
  isbn:
  - '9781450385480'
publication_status: published
publisher: Association for Computing Machinery
quality_controlled: '1'
status: public
title: Component stability in low-space massively parallel computation
type: conference
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
year: '2021'
...
---
_id: '9935'
abstract:
- lang: eng
  text: "We present a deterministic O(log log log n)-round low-space Massively Parallel
    Computation (MPC) algorithm for the classical problem of (Δ+1)-coloring on n-vertex
    graphs. In this model, every machine has sublinear local space of size n^φ for
    any arbitrary constant φ \\in (0,1). Our algorithm works under the relaxed setting
    where each machine is allowed to perform exponential local computations, while
    respecting the n^φ space and bandwidth limitations.\r\n\r\nOur key technical contribution
    is a novel derandomization of the ingenious (Δ+1)-coloring local algorithm by
    Chang-Li-Pettie (STOC 2018, SIAM J. Comput. 2020). The Chang-Li-Pettie algorithm
    runs in T_local =poly(loglog n) rounds, which sets the state-of-the-art randomized
    round complexity for the problem in the local model. Our derandomization employs
    a combination of tools, notably pseudorandom generators (PRG) and bounded-independence
    hash functions.\r\n\r\nThe achieved round complexity of O(logloglog n) rounds
    matches the bound of log(T_local ), which currently serves an upper bound barrier
    for all known randomized algorithms for locally-checkable problems in this model.
    Furthermore, no deterministic sublogarithmic low-space MPC algorithms for the
    (Δ+1)-coloring problem have been known before."
acknowledgement: This work is partially supported by a Weizmann-UK Making Connections
  Grant, the Centre for Discrete Mathematics and its Applications (DIMAP), IBM Faculty
  Award, EPSRC award EP/V01305X/1, European Research Council (ERC) Grant No. 949083,
  the Minerva foundation with funding from the Federal German Ministry for Education
  and Research No. 713238, and the European Union’s Horizon 2020 programme under the
  Marie Skłodowska-Curie grant agreement No 754411.
article_processing_charge: No
author:
- first_name: Artur
  full_name: Czumaj, Artur
  last_name: Czumaj
- first_name: Peter
  full_name: Davies, Peter
  id: 11396234-BB50-11E9-B24C-90FCE5697425
  last_name: Davies
  orcid: 0000-0002-5646-9524
- first_name: Merav
  full_name: Parter, Merav
  last_name: Parter
citation:
  ama: 'Czumaj A, Davies P, Parter M. Improved deterministic (Δ+1) coloring in low-space
    MPC. In: <i>Proceedings of the 2021 ACM Symposium on Principles of Distributed
    Computing</i>. Association for Computing Machinery; 2021:469–479. doi:<a href="https://doi.org/10.1145/3465084.3467937">10.1145/3465084.3467937</a>'
  apa: 'Czumaj, A., Davies, P., &#38; Parter, M. (2021). Improved deterministic (Δ+1)
    coloring in low-space MPC. In <i>Proceedings of the 2021 ACM Symposium on Principles
    of Distributed Computing</i> (pp. 469–479). Virtual, Italy: Association for Computing
    Machinery. <a href="https://doi.org/10.1145/3465084.3467937">https://doi.org/10.1145/3465084.3467937</a>'
  chicago: Czumaj, Artur, Peter Davies, and Merav Parter. “Improved Deterministic
    (Δ+1) Coloring in Low-Space MPC.” In <i>Proceedings of the 2021 ACM Symposium
    on Principles of Distributed Computing</i>, 469–479. Association for Computing
    Machinery, 2021. <a href="https://doi.org/10.1145/3465084.3467937">https://doi.org/10.1145/3465084.3467937</a>.
  ieee: A. Czumaj, P. Davies, and M. Parter, “Improved deterministic (Δ+1) coloring
    in low-space MPC,” in <i>Proceedings of the 2021 ACM Symposium on Principles of
    Distributed Computing</i>, Virtual, Italy, 2021, pp. 469–479.
  ista: 'Czumaj A, Davies P, Parter M. 2021. Improved deterministic (Δ+1) coloring
    in low-space MPC. Proceedings of the 2021 ACM Symposium on Principles of Distributed
    Computing. PODC: Symposium on Principles of Distributed Computing, 469–479.'
  mla: Czumaj, Artur, et al. “Improved Deterministic (Δ+1) Coloring in Low-Space MPC.”
    <i>Proceedings of the 2021 ACM Symposium on Principles of Distributed Computing</i>,
    Association for Computing Machinery, 2021, pp. 469–479, doi:<a href="https://doi.org/10.1145/3465084.3467937">10.1145/3465084.3467937</a>.
  short: A. Czumaj, P. Davies, M. Parter, in:, Proceedings of the 2021 ACM Symposium
    on Principles of Distributed Computing, Association for Computing Machinery, 2021,
    pp. 469–479.
conference:
  end_date: 2021-07-30
  location: Virtual, Italy
  name: 'PODC: Symposium on Principles of Distributed Computing'
  start_date: 2021-07-26
date_created: 2021-08-17T18:14:15Z
date_published: 2021-07-21T00:00:00Z
date_updated: 2023-08-17T07:11:03Z
day: '21'
department:
- _id: DaAl
doi: 10.1145/3465084.3467937
ec_funded: 1
external_id:
  isi:
  - '000744439800048'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: http://wrap.warwick.ac.uk/153753
month: '07'
oa: 1
oa_version: Submitted Version
page: 469–479
project:
- _id: 260C2330-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '754411'
  name: ISTplus - Postdoctoral Fellowships
publication: Proceedings of the 2021 ACM Symposium on Principles of Distributed Computing
publication_identifier:
  isbn:
  - 978-1-4503-8548-0
publication_status: published
publisher: Association for Computing Machinery
quality_controlled: '1'
status: public
title: Improved deterministic (Δ+1) coloring in low-space MPC
type: conference
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
year: '2021'
...
---
_id: '7802'
abstract:
- lang: eng
  text: "The Massively Parallel Computation (MPC) model is an emerging model which
    distills core  aspects of distributed and parallel computation. It has been developed
    as a tool to solve (typically graph) problems in systems where the input is distributed
    over many machines with limited space.\r\n\t\r\nRecent work has focused on the
    regime in which machines have sublinear (in $n$, the number of nodes in the input
    graph) space, with randomized algorithms presented for fundamental graph problems
    of Maximal Matching and Maximal Independent Set. However, there have been no prior
    corresponding deterministic algorithms.\r\n\t\r\n\tA major challenge underlying
    the sublinear space setting is that the local space of each machine might be too
    small to store all the edges incident to a single node. This poses a considerable
    obstacle compared to the classical models in which each node is assumed to know
    and have easy access to its incident edges. To overcome this barrier we introduce
    a new graph sparsification technique that deterministically computes a low-degree
    subgraph with additional desired properties. The degree of the nodes in this subgraph
    is small in the sense that the edges of each node can be now stored on a single
    machine. This low-degree subgraph also has the property that solving the problem
    on this subgraph provides \\emph{significant} global progress, i.e., progress
    towards solving the problem for the original input graph.\r\n\t\r\nUsing this
    framework to derandomize the well-known randomized algorithm of Luby [SICOMP'86],
    we obtain $O(\\log \\Delta+\\log\\log n)$-round deterministic MPC algorithms for
    solving the fundamental problems of Maximal Matching and Maximal Independent Set
    with $O(n^{\\epsilon})$ space on each machine for any constant $\\epsilon > 0$.
    Based on the recent work of Ghaffari et al. [FOCS'18], this additive $O(\\log\\log
    n)$ factor is conditionally essential. These algorithms can also be shown to run
    in $O(\\log \\Delta)$ rounds in the closely related model of CONGESTED CLIQUE,
    improving upon the state-of-the-art bound of $O(\\log^2 \\Delta)$ rounds by Censor-Hillel
    et al. [DISC'17]."
article_processing_charge: No
arxiv: 1
author:
- first_name: Artur
  full_name: Czumaj, Artur
  last_name: Czumaj
  orcid: 0000-0002-5646-9524
- first_name: Peter
  full_name: Davies, Peter
  id: 11396234-BB50-11E9-B24C-90FCE5697425
  last_name: Davies
  orcid: 0000-0002-5646-9524
- first_name: Merav
  full_name: Parter, Merav
  last_name: Parter
citation:
  ama: 'Czumaj A, Davies P, Parter M. Graph sparsification for derandomizing massively
    parallel computation with low space. In: <i>Proceedings of the 32nd ACM Symposium
    on Parallelism in Algorithms and Architectures (SPAA 2020)</i>. Association for
    Computing Machinery; 2020:175-185. doi:<a href="https://doi.org/10.1145/3350755.3400282">10.1145/3350755.3400282</a>'
  apa: 'Czumaj, A., Davies, P., &#38; Parter, M. (2020). Graph sparsification for
    derandomizing massively parallel computation with low space. In <i>Proceedings
    of the 32nd ACM Symposium on Parallelism in Algorithms and Architectures (SPAA
    2020)</i> (pp. 175–185). Virtual Event, United States: Association for Computing
    Machinery. <a href="https://doi.org/10.1145/3350755.3400282">https://doi.org/10.1145/3350755.3400282</a>'
  chicago: Czumaj, Artur, Peter Davies, and Merav Parter. “Graph Sparsification for
    Derandomizing Massively Parallel Computation with Low Space.” In <i>Proceedings
    of the 32nd ACM Symposium on Parallelism in Algorithms and Architectures (SPAA
    2020)</i>, 175–85. Association for Computing Machinery, 2020. <a href="https://doi.org/10.1145/3350755.3400282">https://doi.org/10.1145/3350755.3400282</a>.
  ieee: A. Czumaj, P. Davies, and M. Parter, “Graph sparsification for derandomizing
    massively parallel computation with low space,” in <i>Proceedings of the 32nd
    ACM Symposium on Parallelism in Algorithms and Architectures (SPAA 2020)</i>,
    Virtual Event, United States, 2020, no. 7, pp. 175–185.
  ista: 'Czumaj A, Davies P, Parter M. 2020. Graph sparsification for derandomizing
    massively parallel computation with low space. Proceedings of the 32nd ACM Symposium
    on Parallelism in Algorithms and Architectures (SPAA 2020). SPAA: Symposium on
    Parallelism in Algorithms and Architectures, 175–185.'
  mla: Czumaj, Artur, et al. “Graph Sparsification for Derandomizing Massively Parallel
    Computation with Low Space.” <i>Proceedings of the 32nd ACM Symposium on Parallelism
    in Algorithms and Architectures (SPAA 2020)</i>, no. 7, Association for Computing
    Machinery, 2020, pp. 175–85, doi:<a href="https://doi.org/10.1145/3350755.3400282">10.1145/3350755.3400282</a>.
  short: A. Czumaj, P. Davies, M. Parter, in:, Proceedings of the 32nd ACM Symposium
    on Parallelism in Algorithms and Architectures (SPAA 2020), Association for Computing
    Machinery, 2020, pp. 175–185.
conference:
  end_date: 2020-07-17
  location: Virtual Event, United States
  name: 'SPAA: Symposium on Parallelism in Algorithms and Architectures'
  start_date: 2020-07-15
date_created: 2020-05-06T08:53:34Z
date_published: 2020-07-01T00:00:00Z
date_updated: 2024-02-28T12:53:09Z
day: '01'
department:
- _id: DaAl
doi: 10.1145/3350755.3400282
ec_funded: 1
external_id:
  arxiv:
  - '1912.05390'
  isi:
  - '000744436200015'
isi: 1
issue: '7'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/1912.05390
month: '07'
oa: 1
oa_version: Preprint
page: 175-185
project:
- _id: 260C2330-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '754411'
  name: ISTplus - Postdoctoral Fellowships
publication: Proceedings of the 32nd ACM Symposium on Parallelism in Algorithms and
  Architectures (SPAA 2020)
publication_status: published
publisher: Association for Computing Machinery
quality_controlled: '1'
related_material:
  record:
  - id: '9541'
    relation: later_version
    status: public
scopus_import: '1'
status: public
title: Graph sparsification for derandomizing massively parallel computation with
  low space
type: conference
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
year: '2020'
...
---
_id: '7803'
abstract:
- lang: eng
  text: "We settle the complexity of the (Δ+1)-coloring and (Δ+1)-list coloring problems
    in the CONGESTED CLIQUE model by presenting a simple deterministic algorithm for
    both problems running in a constant number of rounds. This matches the complexity
    of the recent breakthrough randomized constant-round (Δ+1)-list coloring algorithm
    due to Chang et al. (PODC'19), and significantly improves upon the state-of-the-art
    O(logΔ)-round deterministic (Δ+1)-coloring bound of Parter (ICALP'18).\r\nA remarkable
    property of our algorithm is its simplicity. Whereas the state-of-the-art randomized
    algorithms for this problem are based on the quite involved local coloring algorithm
    of Chang et al. (STOC'18), our algorithm can be described in just a few lines.
    At a high level, it applies a careful derandomization of a recursive procedure
    which partitions the nodes and their respective palettes into separate bins. We
    show that after O(1) recursion steps, the remaining uncolored subgraph within
    each bin has linear size, and thus can be solved locally by collecting it to a
    single node. This algorithm can also be implemented in the Massively Parallel
    Computation (MPC) model provided that each machine has linear (in n, the number
    of nodes in the input graph) space.\r\nWe also show an extension of our algorithm
    to the MPC regime in which machines have sublinear space: we present the first
    deterministic (Δ+1)-list coloring algorithm designed for sublinear-space MPC,
    which runs in O(logΔ+loglogn) rounds."
article_processing_charge: No
arxiv: 1
author:
- first_name: Artur
  full_name: Czumaj, Artur
  last_name: Czumaj
  orcid: 0000-0002-5646-9524
- first_name: Peter
  full_name: Davies, Peter
  id: 11396234-BB50-11E9-B24C-90FCE5697425
  last_name: Davies
  orcid: 0000-0002-5646-9524
- first_name: Merav
  full_name: Parter, Merav
  last_name: Parter
citation:
  ama: 'Czumaj A, Davies P, Parter M. Simple, deterministic, constant-round coloring
    in the congested clique. In: <i>Proceedings of the 2020 ACM Symposium on Principles
    of Distributed Computing</i>. Association for Computing Machinery; 2020:309-318.
    doi:<a href="https://doi.org/10.1145/3382734.3405751">10.1145/3382734.3405751</a>'
  apa: 'Czumaj, A., Davies, P., &#38; Parter, M. (2020). Simple, deterministic, constant-round
    coloring in the congested clique. In <i>Proceedings of the 2020 ACM Symposium
    on Principles of Distributed Computing</i> (pp. 309–318). Salerno, Italy: Association
    for Computing Machinery. <a href="https://doi.org/10.1145/3382734.3405751">https://doi.org/10.1145/3382734.3405751</a>'
  chicago: Czumaj, Artur, Peter Davies, and Merav Parter. “Simple, Deterministic,
    Constant-Round Coloring in the Congested Clique.” In <i>Proceedings of the 2020
    ACM Symposium on Principles of Distributed Computing</i>, 309–18. Association
    for Computing Machinery, 2020. <a href="https://doi.org/10.1145/3382734.3405751">https://doi.org/10.1145/3382734.3405751</a>.
  ieee: A. Czumaj, P. Davies, and M. Parter, “Simple, deterministic, constant-round
    coloring in the congested clique,” in <i>Proceedings of the 2020 ACM Symposium
    on Principles of Distributed Computing</i>, Salerno, Italy, 2020, pp. 309–318.
  ista: 'Czumaj A, Davies P, Parter M. 2020. Simple, deterministic, constant-round
    coloring in the congested clique. Proceedings of the 2020 ACM Symposium on Principles
    of Distributed Computing. PODC: Symposium on Principles of Distributed Computing,
    309–318.'
  mla: Czumaj, Artur, et al. “Simple, Deterministic, Constant-Round Coloring in the
    Congested Clique.” <i>Proceedings of the 2020 ACM Symposium on Principles of Distributed
    Computing</i>, Association for Computing Machinery, 2020, pp. 309–18, doi:<a href="https://doi.org/10.1145/3382734.3405751">10.1145/3382734.3405751</a>.
  short: A. Czumaj, P. Davies, M. Parter, in:, Proceedings of the 2020 ACM Symposium
    on Principles of Distributed Computing, Association for Computing Machinery, 2020,
    pp. 309–318.
conference:
  end_date: 2020-08-07
  location: Salerno, Italy
  name: 'PODC: Symposium on Principles of Distributed Computing'
  start_date: 2020-08-03
date_created: 2020-05-06T09:02:14Z
date_published: 2020-07-01T00:00:00Z
date_updated: 2021-01-12T08:15:37Z
day: '01'
ddc:
- '000'
department:
- _id: DaAl
doi: 10.1145/3382734.3405751
ec_funded: 1
external_id:
  arxiv:
  - '2009.06043'
file:
- access_level: open_access
  checksum: 46fe4fc58a64eb04068115573f631d4c
  content_type: application/pdf
  creator: pdavies
  date_created: 2020-10-08T08:17:36Z
  date_updated: 2020-10-08T08:17:36Z
  file_id: '8624'
  file_name: ColoringArxiv.pdf
  file_size: 520051
  relation: main_file
  success: 1
file_date_updated: 2020-10-08T08:17:36Z
has_accepted_license: '1'
language:
- iso: eng
month: '07'
oa: 1
oa_version: Submitted Version
page: 309-318
project:
- _id: 260C2330-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '754411'
  name: ISTplus - Postdoctoral Fellowships
publication: Proceedings of the 2020 ACM Symposium on Principles of Distributed Computing
publication_status: published
publisher: Association for Computing Machinery
quality_controlled: '1'
status: public
title: Simple, deterministic, constant-round coloring in the congested clique
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2020'
...
