September 5, 2024: Lehigh ISE is holding Modeling and Optimization: Theory and Applications (MOPTA) 2025 Conference, in Ponta Delgada, Azores, Portugal during June 17-20, 2025. We will be celebrating the 70th Birthday of Professor Tamás Terlaky, who founded MOPTA 25 years ago. There will be a Tamas-70 Session and Dinner on June 18, 2025.

September 5, 2024: The Portuguese American Optimization Workshop (PAOW), a satellite event of MOPTA 2025, will take place in Horta, Azores, Portugal during June 13-15, 2025. PAOW is primarily focused on continuous optimization and its applications to machine learning.

July 30, 2024: Industrial and Systems Engineering (ISE) at Lehigh University is organizing the first edition of Industrial Modeling and Optimization: Theory and Applications (iMOPTA), August 16, 2024, focused on energy and sustainability. iMOPTA is a one-day event aimed at presenting and discussing industrial innovation and the research behind it, to connect industry and academia more actively. This new half-day workshop is a satellite event of the annual Lehigh ISE flagship conference MOPTA.

July 9, 2024: Oumaima Sohab successfully defended her PhD thesis titled Full-Low Evaluation Methods For Derivative-Free Optimization at Lehigh University, Department of Industrial and Systems Engineering. The defense took place July 9, 2024, via Zoom. Oumaima will start her new job as research scientist at Meta in July. Congratulaions Oumaima!

April 9, 2024: Two new papers are out, co-authored with undergraduate students:
L. N. Vicente, T. N. Alleck, T. Giovannelli, R. Mitchell, and O. Remen, Why is soccer so popular: Understanding underdog achievement and randomness in team ball sports, ISE Technical Report 24T-004, Lehigh University PDF
T. N. Alleck, L. N. Vicente, T. Giovannelli, R. Mitchell, and O. Remen, Match score dataset for team ball sports, ISE Technical Report 24T-003, Lehigh University PDF

November 21, 2023: A new paper is out: T. Giovannelli, O. Sohab, and L. N. Vicente, The limitation of neural nets for approximation and optimization, ISE Technical Report 23T-027, Lehigh University PDF

October 1, 2023: A new paper is out: C. W. Royer, O. Sohab, and L. N. Vicente, Full-low evaluation methods for bound and linearly constrained derivative-free optimization, ISE Technical Report 23T-025, Lehigh University PDF

September 12, 2023: Lehigh University is ranked #14 in the latest version of the Wall Street Journal College rankings: 2024 Best Colleges in the U.S..

July 29, 2023: To incentivize in-person regional/sectional meetings, we are sharing SIAM SIAG on Optimization membership numbers broken down per section and country. In our last business meeting at SIOPT 2023, we discussed the possibility of encouraging local workshops and meetings, so as to promote collaborations, support early career researchers, and further strengthen our community. Please feel free to reach out to us if you have any questions.

June 15, 2023: A revision of the paper A weak tail-bound probabilistic condition for function estimation in stochastic derivative-free optimization is available under a new title Stochastic trust-region and direct-search methods: A weak tail bound condition and reduced sample sizing PDF. The new tail condition allows us to select the stepsize power used for sufficient decrease in such a way to reduce the number of samples needed per iteration when compared to previous works. The analysis of stochastic algorithms is simpler under the new condition. Stochastic trust-region methods are proved globally convergent in the non-smooth case. Check it out!

May 31, 2023: Click here for the slides of the Business Meeting, SIAG on Optimization, 2023 SIAM Conference on Optimization, May 31, 2023.

April 16, 2023: It is already available the program for the 2023 SIAM Conference on Optimization, May 31 - June 3, Seattle, Washington, USA. The SIAG on Optimization has new officers elected for 2023-2025!

February 11, 2023: A new paper is out: T. Giovannelli, G. Kent, and L. N. Vicente, Bilevel optimization with a multi-objective lower-level problem: Risk-neutral and risk-averse formulations, ISE Technical Report 23T-013, Lehigh University PDF

October 7, 2022: A new paper is out: T. Giovannelli and L. N. Vicente, An integrated assignment, routing, and speed model for roadway mobility and transportation with environmental, efficiency, and service goals, ISE Technical Report 22T-013, Lehigh University PDF

July 22, 2022: ICCOPT 2022 is starting tomorrow! Go Lehigh ISE!

April 22, 2022: Suyun Liu successfully defended her PhD thesis titled Stochastic Multi-Objective Optimization and Its Application to Fairness in Machine Learning at Lehigh University, Department of Industrial and Systems Engineering. The defense took place April 19, 2022, via Zoom. Suyun will start her new job as data scientist at Amazon in July. Congratulations Suyun!

March 20, 2022: A new paper is out: S. Liu and L. N. Vicente, Convergence rates of the stochastic alternating algorithm for bi-objective optimization, ISE Technical Report 22T-004, Lehigh University PDF

February 23, 2022: A new paper is out: F. Rinaldi, L. N. Vicente, and D. Zeffiro, A weak tail-bound probabilistic condition for function estimation in stochastic derivative-free optimization, ISE Technical Report 22T-002, Lehigh University PDF

January 11, 2022: Lili Song successfully defended her PhD thesis titled Modeling Hessian-Vector Products in Nonlinear Optimization: New Hessian-Free Methods at the University of Coimbra, in Applied Mathematics. The defense took place January 4, 2022, via Zoom. Congratulations Lili!

November 24, 2021: Suyun Liu: Working toward bias-free machines. Well deserved highlight!

November 10, 2021: A new PhD student started thesis work under my supervision in September 2021: Griffin Kent. Welcome Griffin!

October 7, 2021: Tommaso Giovannelli is a postdoctoral researcher working in our group since June 1, 2021. Welcome Tommaso!

October 1, 2021: A new paper is out: T. Giovannelli, G. Kent, and L. N. Vicente, Bilevel stochastic methods for optimization and machine learning: Bilevel stochastic descent and DARTS, ISE Technical Report 21T-025, Lehigh University PDF

August 11, 2021: A new paper is out: S. Liu and L. N. Vicente, The Sharpe predictor for fairness in machine learning, ISE Technical Report 21T-012, Lehigh University PDF

July 27, 2021: A new paper is out: A. S. Berahas, O. Sohab, and L. N. Vicente, Full-low evaluation methods for derivative-free optimization, ISE Technical Report 21T-016, Lehigh University PDF

June 1, 2021: A new paper is out: S. Liu and L. N. Vicente, A stochastic alternating balance k-means algorithm for fair clustering, ISE Technical Report 21T-012, Lehigh University PDF

May 21, 2021: 2021 MOPTA Conference and AIMMS-MOPTA Optimization Modeling Competition will be held at Lehigh University, August 2-4, 2021. The list of conference plenary speakers is absolutely outstanding!

MOPTA 2021 will be offered in an innovative dual VIRT/IPVS mode. Participants will select between two attendance modes (all guests will experience the talks in the same format):

• Virtual (VIRT), as meetings have been held during the pandemic (via Zoom). VIRT participants and speakers will actually not be able to tell that there is another mode.
  
  
• In-Person Virtual-Sharing (IPVS), as on-campus meetings were held before the pandemic with the single exception that all speakers will present remotely. IPVS participants will be able to attend talks together in rooms equipped with large screens and room sound system. Questions are asked via personal laptops and/or cell phones in the Zoom chat. IPVS participants will share an in-person social program (coffee breaks, lunches, dinners, etc.). IPVS speakers will be assigned a room/office to deliver their talks remotely using their laptops, and can then interact in-person with IPVS participants after their virtual talks.

December 12, 2020: A new PhD student started thesis work under my supervision in September 2020: Oumaima Sohab. Welcome Oumaima!

November 11, 2020: The paper S. Gratton, C. W. Royer, L. N. Vicente, and Z. Zhang, Direct search based on probabilistic feasible descent for bound and linearly constrained problems, Computational Optimization and Applications, 72 (2019) 525-559 was granted the 2019 Computational Optimization and Applications Best Paper Award.

The COAP Best Paper Award exists since 2003. Each year, the editorial board of COAP selects a paper from the preceding year's publications for the Best Paper Award. Two of the 92 papers published by the journal in 2019 tied for the award.

October 30, 2020: A new paper is out: B. Ramos, D. Pinho, D. Martins, A. I. F. Vaz, and L. N. Vicente, Optimal 3D printing of complex objects in a 5-axis printer, ISE Technical Report 20T-024, Lehigh University PDF

October 10, 2020: ICCOPT 2022 will be at Lehigh! The Department of Industrial and Systems Engineering of Lehigh University is extremely proud to host the Seventh International Conference on Continuous Optimization of the Mathematical Optimization Society. The Organizing Committee (co-chaired by Daniel R. Robinson and Frank E. Curtis) and the ISE Department will do their very best to make it a memorable event!

September 27, 2020: Two documents of possible interest: A Note on Three Roles of a Department Chair and An Engineering Department in a Research University.

August 3, 2020: A new paper is out: S. Liu and L. N. Vicente, Accuracy and fairness trade-offs in machine learning: A stochastic multi-objective approach, ISE Technical Report 20T-016, Lehigh University PDF

April 21, 2020: Suyun and I prepared a review talk on the basics of deterministic MOO: A Review of Multi-Objective Optimization: Theory and Algorithms.

March 4, 2020: I am sharing the slides of a talk I have been giving recently (IMPA Brazil, Math Lehigh, IE UPitt, and ISE UMinn): Stochastic Optimization of Multiple Objectives and Supervised Machine Learning.

Another talk has also been released: Trust-Region Methods for the Derivative-Free Optimization of Nonsmooth Black-Box Functions

December 22, 2019: A new paper is out. There is a new method to model Newton directions when using Hessian-vector products that seems quite promising! Check out the details: L. Song and L. N. Vicente, Modeling Hessian-vector products in nonlinear optimization: New Hessian-free methods, ISE Technical Report 19T-031, Lehigh University PDF

November 8, 2019: A new PhD student started thesis work under my supervision in September 2018: Suyun Liu. The work has started more than a year ago but the announcement was forgot... Suyun has been working on stochastic multi-objective optimization and fairness in machine learning. Soon we will start new projects in conflicting robotic learning and green logistics for mobility and transportation. Welcome Suyun!

July 9, 2019: A new paper is out: S. Liu and L. N. Vicente, The stochastic multi-gradient algorithm for multi-objective optimization and its application to supervised machine learning, ISE Technical Report 19T-011, Lehigh University PDF

April 22, 2019: A new paper is out: G. Liuzzi, F. Rinaldi, S. Lucidi, and L. N. Vicente, Trust-region methods for the derivative-free optimization of nonsmooth black-box functions, ISE Technical Report 19T-003, Lehigh University PDF

March 14, 2019: MATLAB's pareto search Algorithm for multiobjective optimization without derivatives is based on our direct multisearch approach:

• A. L. Custódio, J. F. A. Madeira, A. I. F. Vaz, and L. N. Vicente, Direct multisearch for multiobjective optimization, SIAM Journal on Optimization, 21 (2011) 1109-1140 PDF

January 19, 2019: I am releasing the Concise Lecture Notes on Optimization Methods for Machine Learning and Data Science. These lecture notes are publicly available but their use for teaching or even research purposes requires citing:

• L. N. Vicente, S. Gratton, and R. Garmanjani, Concise Lecture Notes on Optimization Methods for Machine Learning and Data Science, ISE Department, Lehigh University, January 2019.

If appropriate, the corresponding source references given at the end of these notes should be cited instead. These lecture notes are displayed in the form of slides for teaching convenience.

January 19, 2019: I'm re-starting the miniblog here, keeping the complete version here. I hope I'll continue to have something interesting to say once in a while...

July 23, 2018: This year edition of MOPTA is a special one. It is combined with an NSF-TRIPODS sponsored three day summer school for doctoral students and the NSF-DIMACS sponsored workshop on Optimization in Machine Learning. A great event, not to be missed!

June 29, 2018: ISMP 2018 is just a fews days away! The International Symposia on Mathematical Programming are the flagship conferences of our dear Mathematical Optimization Society, and the 2018 edition is the 23rd one. ISMPs are held every three years and have been growing recently in size, one reason being the current popularity of Optimization in the Machine Learning community.

June 11, 2018: The 6th IMA Conference on Numerical Linear Algebra and Optimization will soon be held at the University of Birmingham during July 27-29, 2018. This conference series puts together numerical linear algebraists and optimizers following the combination that led to the development of the most efficient methods for numerically solving optimization problems. The Institute for Mathematics and its Applications has been around since 1964 (!) --- and its impact in promoting and supporting Applied Mathematics (journals, prizes, conferences, teaching, dissemination) has been so significant, not only in the UK but around the world.

May 25, 2018: Lehigh University has officially announced it: New ISE Department Chair. Here is what I have to say:

I have been interested in Optimization all my research life, from various viewpoints: Theory and algorithms, software development, and industrial applications. I am thus eager to chair a Department of Industrial and Systems Engineering where Optimization and Operations Research play such a crucial role.

Lehigh's ISE Department is one of the most prestigious in the US, and has enjoyed a strong reputation from the early days of Industrial Engineering through its recent strength in Optimization developed under the leadership of Professor Tamás Terlaky. I am proud to get on board with this fantastic venture, and to further contribute to the development of ISE at Lehigh.

There were so many people who made this possible but let me point Katya Scheinberg, Jorge Nocedal, Tamás Terlaky, and the Dean of Engineering Stephen P. DeWeerth. I extend my gratitude to all ISE Faculty (Ted Ralphs and Frank Curtis in particular), to Associate Dean Svetlana Tatic-Lucic, to the Provost and Dean Offices, and to the colleagues who wrote the recommendation letters. I cannot forget how kind so many faculty and staff members of Lehigh have been in these last 6 months.

Let me finish by thanking the University of Coimbra, its School of Sciences and Technology, and the Department of Mathematics for nearly 30 years of enduring support.

May 16, 2018: Another paper has now been released:

S. Pereira, A. I. F. Vaz, and L. N. Vicente, On the optimal object orientation in additive manufacturing, to appear in The International Journal of Advanced Manufacturing Technology PDF

April 17, 2018: A new paper is out: J. Fliege, A. I. F. Vaz, and L. N. Vicente, Complexity of gradient descent for multiobjective optimization, preprint 18-12, Dept. Mathematics, Univ. Coimbra PDF

April 4, 2018: Extremely happy to report that former MS student Afonso S. Bandeira (Courant, NYU) was awarded a fellowship from the Alfred P. Sloan Foundation. No doubt that Afonso (MS from Coimbra and PhD from Princeton) is among those "whose achievements mark them as among the very best scientific minds working today". Congratulations Afonso!

March 3, 2018: An advertisement to Les Journées SMAI-MODE, the French Days on Optimization and Decision Science, the biennial meeting of the special interest group (MODE) of the French Society for Industrial and Applied Mathematics (SMAI). The event will take place from March 28 to March 30, 2018, near Grenoble, France.

January 1, 2018: Two new PhD students started their theses work under my supervision in September 2017: Ali Moghanni and Lili Song. Ali is looking at probabilistic direct search for black-box problems and at the application of Optimization in mobile sensing. Lili is studying new second-order methods having in mind problems arising from Deep Learning. [Note: Ali has changed adviser in March 2018 due to my departure to Lehigh, and is now working with Professor Marta Pascoal.]

December 9, 2017: The Vienna Graduate School on Computational Optimization is great example of PhD training in Optimization in Europe. It seems able to attract very good students and provide them an intensive training with course instructors from Austria and abroad.

September 28, 2017: Looking very much forward to the Workshop I: Optimization and Optimal Control for Complex Energy and Property Landscapes, October 2-6, 2017, part of the Long Program Complex High-Dimensional Energy Landscapes, Institute for Pure & Applied Mathematics (IPAM), an NSF Math Institute at UCLA.

September 9, 2017: Optimization 2017 has just ended past Friday. Optimizations are a success enterprise, and the 2017 edition was as good as any previous one. This time there was a one-day workshop to (quite deservedly) celebrate the 60th anniversary of Professor Luís Gouveia. The new PC Chair (Luís Gouveia) has announced in the closing session that the next edition will happen in 2020 and that it will be organized by Agostinho Agra as OC Chair.

August 24, 2017: I am back to Univ. Coimbra after a one-year sabbatical abroad as visiting professor (one month at Sapienza/Rome and ten months at Rice/Houston). I am extremely grateful to the fantastic hospitality, in particular to my hosts Professors Stefano Lucidi and Matthias Heinkenschloss.

July 3, 2017: It will start in one week the conference FoCM 2017 - Foundations of Computational Mathematics, Barcelona, July 10-19, 2017. The Workshop on Continuous Optimization will take place during the last three days (July 17-19).

June 18, 2017: Early registration in Optimization 2017 is approaching fast!

April 25, 2017: Another paper has now been released:

S. Gratton, N. Soualmi, and L. N. Vicente, An indicator for the switch from derivative-free to derivative-based optimization, under minor review in Operations Research Letters PDF

April 21, 2017: A new paper is out: S. Gratton, C. W. Royer, and L. N. Vicente, A decoupled first/second-order steps technique for nonconvex nonlinear unconstrained optimization with improved complexity bounds, preprint 17-21, Dept. Mathematics, Univ. Coimbra PDF

March 3, 2017: Yesterday, for my students, I wrote a schematic summary of global rates and worst case complexity (WCC) bounds for the main techniques in smooth continuous optimization. Click here for a picture of my office board.

February 17, 2017: Two new papers are out:

S. Gratton, C. W. Royer, L. N. Vicente, and Z. Zhang, Direct search based on probabilistic feasible descent for bound and linearly constrained problems, preprint 17-10, Dept. Mathematics, Univ. Coimbra PDF

S. Gratton, C. W. Royer, L. N. Vicente, and Z. Zhang, Complexity and global rates of trust-region methods based on probabilistic models, preprint 17-09, Dept. Mathematics, Univ. Coimbra PDF

January 24, 2017: 2017 MACHINE LEARNING @ RICE What a great one-day meeting!

January 10, 2017: There is a new survey paper on Derivative-Free Optimization: A. L. Custódio, K. Scheinberg, and L. N. Vicente, Methodologies and software for derivative-free optimization, Chapter 37 of Advances and Trends in Optimization with Engineering Applications, T. Terlaky, M. F. Anjos, and S. Ahmed (editors), MOS-SIAM Book Series on Optimization, SIAM, Philadelphia, 2017. Click here for the PDF file.

November 4, 2016: Today Clément W. Royer has very successfully defended his PhD thesis titled Derivative-Free Optimization Methods based on Probabilistic and Deterministic Properties: Complexity Analysis and Numerical Relevance at the Université Toulouse 3 Paul Sabatier in the Domaine Mathématiques (Mathématiques Appliquées).

The committee was formed by Jean-Baptiste Hiriart-Urruty (chair), Samir Adly and Amir Beck (rapporteurs), Jean-Baptiste Caillau, Anne Gazaix, and by Serge Gratton and myself as supervisors.

Clément defended very well, not only during his 45-minute presentation, but also when replying to the committee members' questions. Two chapters of his thesis are papers published in SIAM J. on Optimation and Optimization, and two or three others will be submitted soon (all co-authored with Serge, myself, and some with our dear and instrumental collaborator Zaikun Zhang, now in Hong Kong). We are all of course extremely happy for this outstanding achievement unanimously reaffirmed by a committee of the highest quality.

October 3, 2016: It is being a privilege to participate at the Colloquium of the Department of Computational and Applied Mathematics of Rice University and at the Scientific Computing Seminars of the Department of Mathematics of the University of Houston.

August 15, 2016: I am on sabbatical leave from the University of Coimbra during the academic year 2016/2017. I visited Sapienza -- Università di Roma for one month this Summer. I am visiting Rice University from August 2016 to May/June 2017.

July 21, 2016: Very, very sad news, unfortunately:
NA Digest Wednesday, July 18, 2016 Volume 16: Issue 27
"It is with great sadness that we report the death of Roger Fletcher, an Emeritus Professor and Senior Research Fellow at the University of Dundee. Roger was in the first rank of numerical analysts, working mainly in linear algebra and optimization. He is particularly known for his wide ranging work in optimization, where he made many highly original and fundamentally important contributions, and numerous methods bear his name. In addition to the development of methods, Roger also produced several computer programs based on his work which are widely used today. He collaborated widely, and supervised many students and research fellows who went on to make their own major contributions.

The quality of his work was recognised by various honours. He was awarded the Dantzig Prize in 1997 and the Lagrange Prize in 2006, both by the Mathematical Optimization Society; he was elected a Fellow of the Royal Society of Edinburgh in 1988, a Fellow of the Royal Society of London in 2003, a SIAM Fellow in 2009 and was awarded a Royal Medal by the Royal Society of Edinburgh in 2011.

Away from Mathematics, he was an enthusiastic swimmer, an accomplished bridge player, and enjoyed walking in the Scottish hills. It was during a walk from his holiday accommodation near Dornie on the west coast of Scotland that Roger went missing, but the details of what caused his death are still unclear.

Roger was a good friend to many, and splendid company at all times. He leaves a wife Mary, and two daughters Jane and Sarah. He will be greatly missed.

David Griffiths and Alistair Watson"

May 29, 2016: A great day is approaching, that of the beginning of the Workshop on Nonlinear Optimization Algorithms and Industrial Applications, June 2-4, 2016, The Fields Institute, Toronto, celebrating the 70th birthday of Professor Andrew R. Conn (University of Waterloo) then Dr. Andrew R. Conn (IBM T.J. Watson Research Center). The organizers have put up an excellent program. As they say in the webpage

"The workshop will celebrate the 70th birthday of Andrew R. Conn, who, arguably more than anyone, has made major contributions both to the theory of algorithms for nonlinear optimization and application of algorithms through high performance software tools to solve industrial optimization problems of critical importance."

In addition to all of this, Andy has always contributed generously to the Optimization/OR community, impacting the life of so many researchers and practionioners. Thanks Andy and ... congratulations!

April 22, 2016: Giulio Galvan and Martina Sereni have very successfully defended their MS theses respectively titled Optimization methods for recurrent neural networks training and Feature selection using LASSO sparse optimization methods at the Department of Information Engineering of the Università degli Studi di Firenze, under a co-supervision of Professor Marco Sciandrone and myself. Their theses committee counted also with Professor Fabio Schoen. Congratulations to both!

The whole MS defense procedure was much different from the Portuguese. Eleven students defended in the same afternoon, giving their 15-20 min. presentations consecutively, with only a couple of questions after each. An overall committee was chaired by the head of the department. The committee meeting was incredibly fast: the chair suggested the final grades and mentions based on previous course grades, quality of the presentations, and advisers assessments in certain cases. Outside there was a crowd of relatives and friends of the candidates. The overall committee stood by the chair while he was announcing the final scores and then a loud applause was heard and the party began!

March 11, 2016: Yesterday, it was held at the IFP School, in Paris, the PhD defense of Benoît Pauwels. It was a pleasure to be participate in the committee (chaired by Professor Grégoire Allaire). Benoît and his PhD advisers (Professors Frédéric Delbos and Serge Gratton) can indeed be congratulated. The thesis is titled Optimisation sans dérivées sous incertitudes à des simulateurs coûteux. Well done!

February 1, 2016: In his talk mentioned below, Steve drew our attention to a paper by David Donoho (Stanford University) titled 50 Years of Data Science based on a presentation by Professor Donoho at the John W. Tukey 100th Birthday Celebration (Princeton University). I have read Version 1.00, dated Sept. 18, 2015. This manuscript is informative for a wide range of researchers and practitioners dealing with data, whether they do Statistics or Machine Learning or whether they are mathematicians or computer scientists. It is certainly a must for all academic department chairs and deans interested in launching academic programs in Data Science.

January 18, 2016: Last week, it was held in Toulouse a workshop on Optimization and Data Assimilation, CERFACS, January 13-15, 2016, organized by Serge Gratton and Ehouarn Simon, within the CIMI semester on High Performance Linear and Nonlinear Methods for Large Scale Applications. There were great review talks by Yurii Nesterov and Steve Wright on Optimization for Data Science problems!

December 9, 2015: Diogo Júdice has successfully defended his PhD thesis yesterday, here at the University of Coimbra. The committee unanimously granted him the highest grade (distinção and louvor). His thesis contains the results of the paper R. Garmanjani, D. Júdice, and L. N. Vicente, Trust-region methods without using derivatives: Worst case complexity and the non-smooth case, preprint 15-03, Dept. Mathematics, Univ. Coimbra, but it has also a worst case complexity analysis of trust-region methods without derivatives for the determination of second-order stationary points.

September 24, 2015: Two Italian master students have arrived in Coimbra last week. Their names are Giulio Galvan and Martina Sereni, and both have a BS on Information Technology from the Università degli Studi di Firenze. Professor Marco Sciandrone and I will co-advise their theses. They are staying here for 3 months as ERASMUS students and then will defend their theses in Firenze. Giulio will work on learning of recurrent artificial neural networks. Martina will address nonlinear feature selection/ranking problems and nonlinear LASSO type algorithms.

August 3, 2015: I am on vacation... from academic bureaucracy! I am reading "Évariste", a historical novel based on the life of Évariste Galois (par François-Henri Désérable, chez Gallimard, 2015).

July 26, 2015: In the seventies/eighties, papers on algorithms for nonlinear optimization would start by "local convergence", and in the eighties/nineties by "global convergence". At that time, there was a huge excitement about polynomial complexity of interior-point methods. I still remember well Professor Richard Tapia saying once in class that such a polynomial complexity was a qualified form of global convergence (indeed the starting point was arbitrary).

In the nonlinear nonconvex case, algorithms based on Newton or quasi-Newton were purely analyzed from a local, global, and global-to-local view points, which made sense. Even so, twenty or thirty years ago, optimizers were already developing WCC bounds/global rates for nonlinear optimization algorithms but mostly for first-order methods and typically under convexity and smoothness.

With the appearance of the information processing applications (most notably compressed sensing and machine learning), first-order methods become (and still are) very popular.

From here to start developing WCC bounds/global rates for other algorithms (not necessarily first-order ones) was a quick step. The global rates are indeed a tool of interest in the nonlinear case, capable of providing information when the classical global convergence or local analysis do not. It helped, for instance, understanding better cubic regularization methods. In the derivative-free case, as the methods are "zero-order", one can only hope to derive rates of a global nature.

Now papers on algorithms for nonlinear optimization start by "worst case complexity" or "global rate"...

July 17, 2015: Yet another conference, MOPTA - Modeling and Optimization: Theory and Applications 2015, to be held at Lehigh University. Looking forward...

July 12, 2015: The 22nd International Symposium on Mathematical Programming will start very soon...

July 9, 2015: The issue of vi brings me to this post, the last conference attended, and what a conference! Dr. Iain Duff has been organizing the Sparse Days at CERFACS for two decades. Three editions of the series were held in Saint-Girons, close to the Pyrénées. A large number the most prominent researchers in Numerical Linear Algebra attended the very last one of these, the Sparse Days in St Girons III. Interacting with them, within the scientific program and over fantastic dinners, was indeed quite an experience!
At the dinner table, on the last day of the conference, there were Professors Mario Arioli, Jack Dongarra, Gérard Meurant, Cleve Moler, Michael Saunders, Dan Sorensen, among others, and I realized that many of these legends use vi on a daily basis as I do...

July 9, 2015: Zaikun (Zhang) read my post below and suggested me to include mutt (linux mail reader). Yes, I do use mutt, mainly because I can then edit with vi!

June 16, 2015: Some folks have been asking why don't I start a 'real blog' instead? Well, writing using a university server has plenty of advantages. First, I avoid writing stuff that embarrasses myself, or upsets my department chair or dean. Then, I edit html using vi... What would the world be without stuff like vi or emacs, TeX, scripting, fortran, C++ ... ?

May 27, 2015: Next week I am giving a seminar talk at the Séminaire Pluridisciplinaire d'Optimisation de Toulouse (SPOT) / Multidisciplinary Optimization Seminar in Toulouse (SPOT). Toulouse is one of the best places to do Optimization in the world!

May 6, 2015: Former MS student Afonso Bandeira will join the Courant Institute of Mathematical Sciences of NYU as an Assistant Professor in the Department of Mathematics, with a joint appointment in the NYU Center for Data Science. As this will only happen in the Summer of 2016, Afonso will spend the next academic year in the Department of Mathematics of MIT as an Instructor of Applied Mathematics. Congratulations Afonso! His PhD thesis will be defended later this month in the PACM of Princeton University.
It is a pleasure to remember that a few years ago Afonso won the INFORMS Optimization Society Student Paper Prize of 2013 for the paper A. S. Bandeira, K. Scheinberg, and L. N. Vicente, Computation of sparse low degree interpolating polynomials and their application to derivative-free optimization, Mathematical Programming, 134 (2012) 223-257, corresponding to the master thesis defended in July 2010 in the Department of Mathematics of the University of Coimbra.

April 28, 2015: The Council of the Mathematical Optimization Society (MOS) approved the nomination made by MOS Chair William J. Cook, and as a result I am the new Chair of the Executive Committee of the society. I look forward to helping Bill and the society!

April 23, 2015: Very, very sad news, unfortunately:
NA Digest Wednesday, April 22, 2015 Volume 15: Issue 16
From: Arieh Iserles ai@damtp.cam.ac.uk
Date: April 19, 2015
Subject: MJD Powell
"I am very sad to let the NA-net community know that M.J.D. Powell passed away this morning, 19th April 2015.
Many of the NA community would have known Mike Powell as one of the giants of the Golden Age of numerical analysis and the pioneer of optimization. Indeed, he has been honoured for his achievements, not least by being elected a Fellow of the Royal Society and a Foreign Member of (American) National Academy of Sciences and of Australian Academy of Sciences, but also by the inaugural Dantzig Prize of Mathematical Programming Society, Naylor and Senior Whitehead Prizes of London Mathematical Society, Gold Medal of Institute for Mathematics and its Applications... The list goes on and on. For his many friends, though, he was not just a brilliant mathematician but also a lovely person of total integrity and honesty, a role model in mathematics, a dear friend and a teacher to many. He will be sorely missed."

April 22, 2015: According to Google, my webpage is clearly not mobile-friendly. It has failed pretty badly in the Mobile-Friendly Test...

April 15, 2015: Luís Daniel Abreu is giving a talk in Coimbra next Wednesday, April 22 (16:30, Room 5.5 of the Math. Dept.) titled Harmonic Analysis for the Natural Sciences. It will be a pleasure to listen to his talk. Daniel was our colleague here at the faculty of the Math. Department and teamed up with us in several research grants. Daniel moved to Vienna a couple of years ago. Early this year, he became a Research Associate at the Acoustics Research Institute of the Austrian Academy of Sciences.

April 8, 2015: Youssef Diouanne successfully defended his PhD thesis in October 2014 at the Institut National Polytechnique de Toulouse (École ENSEEIHT). Serge Gratton and I supervised his dissertation, titled Globally Convergent Evolution Strategies with Application to an Earth Imaging Problem in Geophysics. After a short postdoc at CERFACS with Serge, Youssef was offered and accepted an academic tenure track position at the Institut Supérieur de l'Aéronautique et de l'Espace (ISAE) at Toulouse. Il s'agit d'un poste d'enseignant-chercheur en mathématiques appliquées, spécialité optimisation numérique. Congratulations Youssef!

April 1, 2015: The Second Seville Workshop on MINLP has counted with more than seventy participants! The meeting was (partially) funded by the EU Action/Project COST TD1207, titled "Mathematical Optimization in the Decision Support Systems for Efficient and Robust Energy Networks". The existence and success of this project is mainly due to Professor Andrea Lodi (Univ. Bologna) who has been its leader (PI) from the beginning. Andrea has told us that he accepted a professorship position at the École Polytechnique de Montréal. Europe lost another fine scientist. Montréal got another great Mathematical Optimizer!

March 24, 2015: Next week, it will be held in Seville, Spain, the Second Seville Workshop on MINLP. Not all speakers are from Europe or will directly address Mixed Integer Nonlinear Programming in their talks (as it is my case), but the program does show the current European excellence in MINLP.

March 19, 2015: In the paper Direct search based on probabilistic descent (see papers), there is a new proof technique for establishing global rates and worst case complexity bounds for randomized algorithms for which the new iterate depends on some object (directions, models) and the quality of the object is favorable with a certain probability. The technique is based on counting the number of iterations for which the quality is favorable and examining the probabilistic behavior of this number.

March 19, 2015: I'm starting a miniature blog here... I hope I'll have something interesting to say once in a while...