Author Archives: Stephanie Lai

Our Alumni – Younes Chahlaoui

In this blog post, we asked one of our alumni, Younes Chahlaoui, a few questions about his time with the Numerical Linear Algebra Group.
Younes Chahlaoui

Please can you introduce yourself and tell us a bit about your experience before working at the University of Manchester?

I obtained my licence in Applied Mathematics from the University Chouaib Doukkali in my hometown El Jadida, Morocco. Then I got a CIUF grant to do a DEA and a Ph.D. in Mathematical Engineering at INMA, ICTEAM, Polytechnical school at UCLouvain, Belgium. I worked with Prof. Paul Van Dooren.

The title of my Ph.D. is “Low-rank approximation and model reduction.” The central part of my research dealt with developing recursive algorithms for computing low-rank approximations of Gramians of LTI systems that we can use to form reduced models or compute some systems norms. Some of these algorithms are in the SLICOT package.

I did a Postdoc at FSU, Tallahassee, working with Prof. Kyle Gallivan, before working as visiting researcher in different Moroccan universities for three years.

I moved to Manchester in January 2008 for a 4yrs Postdoc within the CICADA EPSRC project.

Why did you choose to take a postdoctoral position in Manchester?

I received the CICADA job announcement and applied. Prof. Nick Higham contacted me for the interview. Working with the NLA group and all CICADA teams was a challenge. The international reputation of the NLA group helped me a lot then and after.

How did you find Manchester?

It was an invaluable experience for my family and me. Even after leaving Manchester in December 2011, we still have many good friends there. My boys are hoping to do their studies at the University of Manchester.

Can you tell us about your career since leaving Manchester?

Since January 2012, I have been working at the Department of Mathematics at King Khalid University, Abha, KSA. Since 2014, I have supervised 4 M.Sc. students, and I am actively participating in developing new academic programs within the department.

What is your current role?

Since the beginning of 2021, I have overseen the Quality & Academic Development (Q&D) unit at the College of Science. We have applied for the National Center for Academic Accreditation and Evaluation accreditation of 4 B.Sc. and 4 M.Sc. programs, awaiting decision soon (June 2022).

I am American Institute of Professional Studies (AIPS) accredited as a consultant in Quality Management System (ISO 9001-2015) and European Foundation for Quality Management (EFQM).

Now I am a member of many committees at different levels at the university related to Learning Outcomes, KPIs, and accreditations.

Nick Higham to give International Congress of Mathematicians Lecture

Professor Nick Higham will give an invited sectional talk at the International Congress of Mathematics (ICM), to be held July 8–12, 2022.

The 2022 ICM is taking place virtually and Nick will deliver his lecture, titled “Numerical Stability of Algorithms at Extreme Scale and Low Precisions”, in person at an overlay conference at Imperial College,

The ICM is the largest conference on mathematics, takes place every four years, and was first held in 1897.

Professor Nicholas J. Higham, University of Manchester

2022 NLA group photo

A new group photo was taken on May 16, 2022—our first in over two years. Most group members are in the photo.

A high resolution version of the photo is available here.

Numerical Linear Algebra Group. By row from the back: Mantas Mikaitis, Xinye Chen, Alban Bloor Rile, Xiaobo (Bob) Liu, Michael Connolly, Nick Higham, Sven Hammarling, Stefan Güttel, Ian McInerney, Bastien Vieuble, Ayana Mussabayeva, Thomas Seleiro, Françoise Tisseur, Marcus Webb.

Our Alumni – Vanni Noferini

In this blog post, we asked one of our alumni, Vanni Noferini, a few questions about his time with the Numerical Linear Algebra Group.

Please can you introduce yourself and tell us a bit about your experience before attending University of Manchester?

I was born in Florence, Tuscany. I did my undergraduate studies there, obtaining an M.Sc. in Theoretical Physics. Later, I got my Ph.D in Mathematics in Pisa. During my PhD I was jointly supervised by Dario Bini and Luca Gemignani. While in Italy I also played volleyball at a somewhat competitive level, and I have had a number of part-time/student jobs. For example I have been writing science popularisation articles for a Swiss newspaper.

Why did you choose to do your postdoc in Manchester?

While I was writing my PhD thesis I had applied to an open call for a postdoc position to work on functions of a matrix, with Nick Higham. Nick is a world-famous superstar in the area, so that sounded like a great opportunity. Moreover, I liked Nick and Françoise, and the rest of the group, since the day of my interview; they probably have also not disliked me too much because I was offered the job. Accepting it was a great decision: I learnt a lot and my time there has certainly shaped my career to a significant extent. I started in September 2012 (technically as a predoc: I flew to Pisa to defend my viva in October 2012) and stayed until August 2015.

During my Manchester years, I have worked not only with Nick but also with many other people who then were in the group: for example Yuji Nakatsukasa, Javi Perez, Meisam Sharify, Françoise Tisseur. Plus there were other fantastic mathematicians around to talk with, such as Stefan Guettel or Martin Lotz  — not to mention the frequent international visitors. Those were the days and Manchester was just the place to be… Now I manage my own research group at Aalto, and I am doing my best to create a similarly fruitful environment: my inspiration for this goal is definitely the NLA group in Manchester during my postdoc!

How did you find Manchester?

A little humid, but fun.  In my first couple of weeks I actually stayed in the Peak District (the husband of a friend of my then girlfriend had rented me a room in Congleton, Cheshire) which was beautiful but would not have been a very convenient long-term address to work in the Alan Turing Building. Thus, I soon moved to Didsbury and I lived there for most of my 3 years in Manchester. I was living in Austin Drive, not far from the Burnage railway station, and apparently very close to where Charles Van Loan had stayed during his own Manchester postdoc (at least, so he once told me). Later, more NLA group members figured out that Didsbury was a rather nice place, so eventually we had grown a small community there. In fact, fellow Didsbury resident Martin Lotz and I used to refer to Manchester as “Greater Didsbury”. On the occasional sunny weekends I liked to go around by car, so I got to know quite well the broader area of Greater Dids… I mean, Manchester, and North-West England.

Can you tell us about your career since leaving University of Manchester?

I have continued a career in academia. I was a Lecturer (Research) at the University of Essex in Colchester for about 4 years. I obtained tenure in Essex, and also indefinite leave to remain in the UK post-Brexit, having got a “settled status” as a long-enough UK resident and EU citizen. However, even though I have enjoyed my 7 years in England, I was offered an attractive position from Aalto University (Finland), that would give me more research time and better funding opportunities. So I moved here in May 2019.

What is your current role?

Currently I am an Associate Professor in Mathematics at Aalto University, which is located in Espoo (Finland). Here I am the leader of a research group on matrix theory and its applications. At the time of this interview, my group includes one visiting professor (Paul Van Dooren), two postdocs (Giovanni Barbarino and Manme Quintana), two PhD students (Lauri Nyman and Ryan Wood) and one MSc student by research (Antti Haavikko). We are having fun!

Numerical Linear Algebra Group Activities 2021

The Numerical Linear Algebra Group had a busy year in 2021, despite the pandemic limiting our travel. This post summarizes what we got up to. Publications are not included here, but many of them can be found on MIMS EPrints under the category Numerical Analysis; see also these news stories about our publications.

Software

Nick Higham and Manta Mikaitis released Anymatrix: a MATLAB toolbox that provides an extensible collection of matrices, organized in groups, with the ability to search the collection by matrix properties. See this blog post by Nick and this blog post by Mantas.

We make our research codes available as open source, principally on GitHub; see the repositories of ConnollyFasiHighamLiu, Mikaitis, PraneshZounon.

We also put MATLAB software on MATLAB Central File Exchange and on our own web sites, e.g., the Rational Krylov Toolbox (RKToolbox).

PhD Students

We welcomed new PhD students Ayana Mussabayeva and Alban Bloor Riley.

Thomas McSweeney (Scheduling with Precedence Constraints in Heterogeneous Parallel Computing) and Gian Maria Negri Porzio (Nonlinear Eigenvalue Problems: Theory and Algorithms) successfully defended their PhD dissertations.

Postdoctoral Research Associates (PDRAs)

Srikara Pranesh left the group in October 2021 and is now working at V-Labs in Bengaluru. He joined us in 2017 to work on the NLAFET  (Parallel Numerical Linear Algebra for Extreme Scale Systems) project and then moved onto the ICONIC project.

Mawussi Zounon left the group in June 2021 to become a senior software engineer at Arm Manchester. He joined us in 2016 to work on the NLAFET project. At the end of the NLAFET project, he continued working with the Numerical Linear Algebra Group as a Knowledge Transfer Partnership (KTP) associate, in partnership with NAG. The KTP, which ended in June 2021, was deemed “Outstanding” by the KTP Grading Panel for its achievement in meeting the KTP Objectives.

Ian McInerney joined the group in December 2021, having completed his PhD in the High Performance Embedded and Distributed Systems (HiPEDS) Centre for Doctoral Training at Imperial College, London, under the supervision of Eric Kerrigan and George Constantinides.

Grants

Nick Higham and Françoise Tisseur received funding for work on multi-precision algorithms from Lawrence Livermore National Laboratory under the Exascale Computing Project.

Françoise Tisseur received EPSRC funding to work on mixed precision symmetric eigensolvers.

Presentations at Conference and Workshops

SIAM Conference on Computational Science and Engineering (virtual), March 1-5: Connolly, Fasi, Higham, Mikaitis, Pranesh, Tisseur.

SIAM Conference on Applied Linear Algebra (virtual), May 17-21: Fasi, Liu.

New Directions in Numerical Linear Algebra and High Performance Computing (virtual) July 7-8, 2021: Hammarling, Higham, Tisseur.

SIAM Annual Meeting 2021(virtual), July 19-23: Connolly, Fasi, Higham, Mary, and Pranesh.

IEEE International Conference on Data Mining (ICDM) 2021, Auckland, New Zealand (virtual), December 7-10: Chen

Conference and Workshop Organization

Stefan Güttel continued to co-organize the E-NLA online seminar series dedicated to topics in Numerical Linear Algebra.

Nick Higham organized a minisymposium on Reduced Precision Arithmetic and Stochastic Rounding at the SIAM Conference on Computational Science and Engineering,  March 1-4, 2021.

Theo Mary and Srikara Pranesh organised a two-part minisymposium on Mixed Precision Algorithms for High Performance Scientific Computingr at the SIAM Conference on Computational Science and Engineering, March 1-5, 2021.

Massimiliano Fasi and Xiaobo Liu organised a two-part minisymposium on Computing Functions of Matrices at the SIAM Conference on Applied Linear Algebra, May 17-21, 2021.

Sven Hammarling, Nick Higham and Françoise Tisseur organized the New Directions in Numerical Linear Algebra and High Performance Computing workshop which was held virtually on July 7-8, 2021, celebrating the 70th birthday of Jack Dongarra. Videos from the workshop are available here.

Rob Corless and Nick Higham organized a two-part minisymposium Bohemian Matrices and Applications at the SIAM Annual Meeting (virtual), July 2021.

Nick Higham and Sri Pranesh organized a two-part minisymposium Computational Frontiers in Numerical Linear Algebra at the SIAM Annual Meeting (virtual), July 2021.

Max Fasi was on the organizing committee of the the 9th Matrix Equations and Tensor Techniques Workshop9-10 September 2021 in Perugia, Italy.

Recognition and Service

Nick Higham was been named a 2020 ACM Fellow.

Stefan Güttel was awarded the 2021 James H. Wilkinson Prize in Numerical Analysis and Scientific Computing.

Nick Higham received the George Pólya Prize for Mathematical Exposition from the Society for Industrial and Applied Mathematics (SIAM).

Nick Higham was awarded the 2022 Hans Schneider Prize by the International Linear Algebra Society (ILAS).

External Members

Max Fasi took up a Lectureship in Computer Science at Durham University in October 2021.

Nick Higham Featured in People of ACM

Professor Nick Higham is featured in a People of ACM profile. “People of ACM” is a bulletin at the Association for Computer Machinery (ACM) highlighting “the unique scientific accomplishments and compelling personal attributes of ACM members who are making a difference in advancing computing as a science and a profession”.

Professor Jack Dongarra was also featured in People of ACM in 2013.

Professor Nicholas J. Higham, University of Manchester

Nick Higham Awarded the 2022 Hans Schneider Prize

Professor Nick Higham has been awarded the 2022 Hans Schneider Prize by the International Linear Algebra Society (ILAS). The Hans Schneider Prize in Linear Algebra is awarded every three years by ILAS for research, contributions, and achievements at the highest level of Linear Algebra.

Nick is cited for his fundamental contributions in the analysis of a wide range of numerical linear algebra problems and matrix functions. He will present his lecture at the 25th ILAS Conference in Madrid, Spain, June 5-9, 2023.

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Professor Nicholas J. Higham, The University of Manchester

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NLA Group Presentations at SIAM Annual Meeting 2021

Members of the Numerical Linear Algebra Group will be giving six presentations at the upcoming SIAM Annual Meeting (AN21). They are also organizing the two-part minisymposiums Computational Frontiers in Numerical Linear Algebra (Part 1, Part 2) and Bohemian Matrices and Applications (Part 1, Part 2).

The conference will be held virtually, from 19th July to 23rd July, 2021.

Here are the dates and times (listed in Eastern Time (UTC-4)) where members of our group will be giving their presentations:

Tuesday 20 July
18:30 – 20:30 Massimiliano Fasi
Cpfloat: A C Library for Emulating Low-Precision Arithmetic (poster)

Wednesday 21 July
14:30 – 15:30 Nick Higham
Past President’s Address – Mixed Precision Numerical Linear Algebra with More Realistic Error Bounds

Thursday 22 July
16:45 – 17:10 Massimiliano Fasi
Determinants of Normalized Bohemian Upper Hessenberg Matrices

Friday 23 July
10:15 – 10:40 Theo Mary
Data-Aware Mixed Precision Algorithms
10:45 – 11:10 Srikara Pranesh 
Random Matrices Generating Large Growth in LU Factorization with Pivoting
11:15 – 11:40 Michael Connolly
Mixed Precision Randomized SVD

More information on AN21 is available here.

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