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A Stochastic LBFGS Algorithm for Radio Interferometric Calibration [article]

Sarod Yatawatta, Lukas De Clercq, Hanno Spreeuw, Faruk Diblen
<span title="2019-04-13">2019</span> <i > arXiv </i> &nbsp; <span class="release-stage" >pre-print</span>
We present a stochastic, limited-memory Broyden Fletcher Goldfarb Shanno (LBFGS) algorithm that is suitable for handling very large amounts of data.  ...  A direct application of this algorithm is radio interferometric calibration of raw data at fine time and frequency resolution.  ...  RADIO INTERFEROMETRIC CALIBRATION In this section we give a brief overview of radio interferometric calibration in relation to the use of the LBFGS algorithm.  ... 
<span class="external-identifiers"> <a target="_blank" rel="external noopener" href="https://arxiv.org/abs/1904.05619v2">arXiv:1904.05619v2</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/fliw2aai5fa33nzx2syzl7if5a">fatcat:fliw2aai5fa33nzx2syzl7if5a</a> </span>
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Stochastic calibration of radio interferometers

Sarod Yatawatta
<span title="2020-03-13">2020</span> <i title="Oxford University Press (OUP)"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/qjdxzupqgjennounydm4zfdlem" style="color: black;">Monthly notices of the Royal Astronomical Society</a> </i> &nbsp;
We propose a 'stochastic' calibration strategy where we only read in a mini-batch of data for obtaining calibration solutions, as opposed to reading the full batch of data being calibrated.  ...  Stochastic calibration overcomes the need for data averaging before any calibration can be performed, and offers many advantages including: enabling the mitigation of faint radio frequency interference  ...  Therefore, we first compare the performance of the stochastic LBFGS algorithm with a widely used gradient descent based optimization method (Adam) Kingma & Ba (2014) in calibration of radio interferometric  ... 
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1093/mnras/staa648">doi:10.1093/mnras/staa648</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/vnggtqsgzvdjro2qlztdnalywe">fatcat:vnggtqsgzvdjro2qlztdnalywe</a> </span>
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Radio Interferometric Calibration Using a Complex Student's t-distribution and Wirtinger Derivatives [article]

Ulrich Armel Mbou Sob, Hertzog Landman Bester, Oleg Smirnov, Jonathan Kenyon, Trienko Grobler
<span title="2019-10-17">2019</span> <i > arXiv </i> &nbsp; <span class="release-stage" >pre-print</span>
We present an algorithm based on a Student's t-distribution which leverages the framework of complex optimisation and Wirtinger calculus for efficient and robust interferometric gain calibration.  ...  Radio interferometric gain calibration can be biased by incomplete sky models and radio frequency interference, resulting in calibration artefacts that can restrict the dynamic range of the resulting images  ...  Radio interferometric gain calibration Let d = [d pq ] and v = [v pq ] respectively represent the vectorised observed and modelled visibilities.  ... 
<span class="external-identifiers"> <a target="_blank" rel="external noopener" href="https://arxiv.org/abs/1910.08136v1">arXiv:1910.08136v1</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/znfhtfx27jbnblb5s43jyypi4a">fatcat:znfhtfx27jbnblb5s43jyypi4a</a> </span>
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M87* in space, time, and frequency [article]

Philipp Arras, Philipp Frank, Philipp Haim, Jakob Knollmüller, Reimar Leike, Martin Reinecke, Torsten Enßlin
<span title="2021-09-15">2021</span> <i > arXiv </i> &nbsp; <span class="release-stage" >pre-print</span>
In this regime, radio astronomical imaging algorithms are brought to their limits.  ...  Our algorithm views the imaging task as a Bayesian inference problem of a time-varying brightness, exploits the correlation structure between time frames, and reconstructs an entire, 2+1+1 dimensional  ...  M.R. provided implementations and numerical optimisation for many of the employed algorithms. T.E. coordinated the team and contributed to discussions.  ... 
<span class="external-identifiers"> <a target="_blank" rel="external noopener" href="https://arxiv.org/abs/2002.05218v4">arXiv:2002.05218v4</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/sg46suwkxfdljjua6utpcvqdqi">fatcat:sg46suwkxfdljjua6utpcvqdqi</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20210918111907/https://arxiv.org/pdf/2002.05218v4.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/76/4d/764dd47610d56b50766fd979f2db0772c16f3472.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener" href="https://arxiv.org/abs/2002.05218v4" title="arxiv.org access"> <button class="ui compact blue labeled icon button serp-button"> <i class="file alternate outline icon"></i> arxiv.org </button> </a>