About two weeks ago, from 10 till 13 Jan 2022 I was at the annual meeting of the French research group on manybody phaenomena, the GDR nbody. Originally scheduled to take place in person in Toulouse the Coronarelated developments unfortunately caused the organisers to switch to a virtual event on …
read moreOutlook to 2022
A quick teaser to some workshops I will organise next year.

17/18 Feb 2022: Introduction to the Julia programming language (virtual).
In two halfday sessions I will provide a concise overview of the Julia programming language and offer to get some handson practice. The selection of exercises and small …

GdR REST Discussion meeting on Machine Learning
Last week on 9th and 10th December 2021 I participated in the Discussion meeting on Machine Learning been organised by the French research group REST, which is centred around theoretical spectroscopy in solids and molecules. While most participants joined remotely I was fortunately able to travel to École Polytechnique in …
read moreA robust and efficient line search for selfconsistent field iterations
In an ongoing effort with Antoine Levitt our aim is to develop reliable densityfunctional theory (DFT) methods for computational materials design. Recently we looked into a strategy to automatically select the damping parameter for the selfconsistent field iterations (SCF). Our adaptive damping approach is based on a theoretically sound quadratic …
read moreJuliaCon DFTK workshop: A mathematical look at electronic structure theory
From 13th July till 30th July this year's JuliaCon finally took place virtually. The first week (13th till 27th) hosted a number of threehour livestreamed sessions of workshops, while the "regular" conference with a number of prerecorded talks started on 28th.
After my introductory talk to electronic structure theory and …
read moreVirtual materials design 2021: Blackbox densityfunctional theory methods
On 20th and 21st July 2021 the Virtual Materials Design 2021 CECAM workshop took place virtually. I was excited about this workshop and the opportunity to get in touch with researchers working on highthroughput computational materials design. While I am not actively working in this field the special requirements of …
read moreSIAM LA: Robust and efficient accelerated methods for densityfunctional theory
Just one day after my talk at the SIAM Materials Science conference (blog article) I gave another talk at a SIAM meeting, this time at SIAM Linear Algebra. I was very much looking forward to participate in SIAM LA, firstly because it was the first time I attended this conference …
read moreSIAM MS: Using the densityfunctional toolkit to design blackbox DFT methods
After being moved by one year due to the pandemic, the last two weeks (from 17th to 28th May) the SIAM materials science conference finally took place in virtual form. Unfortunately this meant that the conference was scheduled in parallel to the SIAM Linear Algebra virtual conference, where I also …
read moreDFTK: A Julian approach for simulating electrons in solids
Following my talk at Juliacon about our DFTK code last year (slides, recording, blog article), we have now published an extended abstract in the JuliaCon proceedings, which you can find below. The JuliaCon proceedings use the same open journals software stack to manage their publication infrastructure as the Journal of …
read moreA novel blackbox preconditioning strategy for highthroughput densityfunctional theory
A couple of weeks ago, from 15th to 19th March, I participated in the virtual annual meeting of the German Association of Applied Mathematics and Mechanics (GAMM). For me this meeting was the first time I presented my work to an audience of applied mathematicians with a broad background and …
read moreCESMIX TST meeting: DFTK.jl: A multidisciplinary Julia code for densityfunctional theory development
These past two days I have participated in the TriLab Support Team (TST) meeting of the CESMIX, the newly founded Center for the Exascale Simulation of Material Interfaces in Extreme Environments at the Massachusetts Institute of Technology. Within the next few years the idea of the CESMIX is to develop …
read moreHighthroughput densityfunctional theory calculations: An interdisciplinary challenge
Last Thursday I was invited to give a virtual talk at the Scientific Computing Seminar of working group of Prof. Nicolas Gauger at TU Kaiserslautern. Since the research in Prof. Gauger's group mostly concerns topics which are not directly related to electronic structure theory and densityfunctional theory (DFT), I chose …
read moreChallenges and prospects of a posteriori error estimation in densityfunctional theory
Last week Wednesday I was invited to give a talk at the group seminar of the AG Christoph Jacob at TU Braunschweig, Germany. Christoph was especially interested in our recent publication on a posteriori error estimation in KohnSham problems and so I decided to use the opportunity to give a …
read moreMoansi: Inhomogeneous preconditioning for densityfunctional theory
Last week (24th and 25th September) I attended the 4th annual meeting of the Moansi (Modelling, analysis and simulation of Molecular Systems) work group of the GAMM. I already attended the Moansi meeting last year, where I very much enjoyed both the broad range of talks at the interdisciplinary border …
read moreFaraday Discussions: New horizons in density functional theory
Following the submission of our paper on a posteriori error estimation in the KohnSham equations a few months ago I was recently invited to present our work at the Faraday Discussions on New horizons in density functional theory. Being amongst speakers such as Kieron Burke, Andreas Savin or Weitao Yang …
read moreBlackbox inhomogeneous preconditioning for selfconsistent field iterations in densityfunctional theory
For the past half a year or so Antoine Levitt and myself have been looking at a particular tricky busyness for solidstate densityfunctional theory (DFT) calculations, namely how to design efficient selfconsistent field (SCF) schemes for large inhomogeneous systems. I have already previously reported on this matter in a short …
read moreDFTK: A Julian approach for simulating electrons in solids
Since last Friday I have been attending JuliaCon, the annual conference for the Julia language. Naturally given the current situation the event did not take place "on location", but was instead converted into a virtual event. Albeit the different feel compared to a reallife conference the organisers did a very …
read moreSCF preconditioning for mixed systems
Fortunately the general lockdown due to the Corona pandemic slowly starts to ease around Paris as well. While basically all seminars are only virtual it is good to see old procedures and habits to slowly return. From my end I gave the first talk after the forced break today in …
read moreFirst release of the densityfunctional toolkit (DFTK)
After we released a preliminary snapshot of DFTK last year our focus in the first half of this year was on using it for some new science. Recently, however, we got back into polishing our code base and our documentation in order to get DFTK ready for a wider audience …
read moreA posteriori error estimation for the nonselfconsistent KohnSham equations
After about a year of work on the densityfunctional toolkit (DFTK) we finally started using the code for some new science. Given the mathematics background of the CERMICS the first two DFTKrelated articles were not so much about largescale applications, but rather deal some fundamental questions of KohnSham densityfunctional theory …
read more1st GDR NBODY meeting in Lille: Applications of DFTK
Earlier this month the first annual meeting of the French working group NBODY (GDR NBODY) took place in Lille. Since the GDR NBODY is an association of interdisciplinary scientists working on Nbody problems in chemistry an physics, the about 80 participants came from a broad background ranging from quantum …
read moreTalk in Toulouse: adcc and DFTK
A few weeks ago on 21st and 22nd November of this year PierreFrancois Loos invited me for two days to the Laboratoire de Chimie et Physique Quantiques of the Université Paul Sabatier Toulouse. On Thursday the 21st I had the chance to present our current status in DFTK and adcc …
read morePreview release of the densityfunctional toolkit (DFTK)
As part of my research stay at the Matherials team of ENPC Paris Tech and Inria I have been developing the densityfunctional toolkit, DFTK.jl, together with Antoine Levitt and Eric Cancès. Finally after about six months of joint effort on this Julia code, we just released a first preview …
read moreJuliaParis: Electronic structure simulations using Julia
Yesterday we had the first instance of the Julia Paris Meetup. As the name suggests a couple of us Julia enthusiasts in the French capital got together for one evening of talks and chatting about everyone's favourite programming language. It was a great occasion to finally meet some people in …
read moreTeasers for some upcoming Julia activities
A quick teaser for some Juliarelated activities around Paris, I am involved with in the next months.

17 Oct 2019, 19:00, QuantStack (27 Rue du Chemin Vert 75011, Paris): The first Julia meetup of Paris. We want to gather the people in and around Paris, who are interested in …

Interdisciplinary software for electronic structure theory: adcc and DFTK
Last week, from Wednesday to Friday, I paid the Technical University of Munich (TUM) a short visit for two great opportunities to present my work: Once in the theoretical chemistry group of Professor Wolfgang Domcke and once at the annual meeting of the modeling, analysis and simulation of molecular systems …
read moreInterdisciplinary software development in electronic structure theory (MQM Poster)
At the beginning of the month, from 30th June till 5th July, I attended the 9th Molecular Quantum Mechanics Conference in my old home Heidelberg. This occasion was a great opportunity to catch up with friends and colleges both in science and from my old circle in Heidelberg as well …
read moreModern softwaredevelopment techniques in electronic structure theory
A few weeks ago, on 23rd May I received an invitation to visit the Laboratoire de Physique des Lasers, Atomes et Molécules at the Université de Lille and present about my recent work. When it came to selecting a topic, me and my host, Andre Gomes, quickly agreed to focus …
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