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 high-throughput computational materials design. While I am not actively working in this field the special requirements of …

read more# SSD Seminar: Accelerating the discovery of tomorrow's materials by robust and error-controlled simulations

A couple of days ago, on 12th July, I was invited to present my research in the SSD Seminar Series of RWTH Aachen. Being part of the research training group on modern inverse problems as well as the School for Simulation and Data Science (SSD) the SSD seminars are interdisciplinary …

read more# Talk at many-body seminar at RWTH

On 29th June I was invited to present a short summary of my research at the seminar of the research training group Quantum Many-Body Methods at RWTH Aachen University. In the talk I give a overview over my ongoing work about reliable black-box self-consistent field schemes for high-throughput DFT calculations …

read more# Errors and uncertainty quantification in density-functional theory

On 8th June I was invited to the seminar of the Uncertainty Quantification (UQ) group of Prof. Youssef Marzouk at MIT. Youssef and I planned to have this seminar since my involvement with MIT's CESMIX project last February (see also this blog article), but it took use quite some time …

read more# Talk at MATH4UQ seminar series at RWTH

On 1st June I was invited to the MATH4UQ seminar series of the Mathematics of Uncertainty Quantification chair of Prof. Raul Tempone at RWTH Aachen University.

Over the past months I got more and more interested in mathematical methods for uncertainty quantification (UQ) as an opportunity to estimate and understand …

read more# SIAM LA: Robust and efficient accelerated methods for density-functional 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 more# SIAM MS: Using the density-functional toolkit to design black-box 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 more# Infomath seminar: A one-hour introduction to Julia

Just one day after my talk at the Lüchow group in Aachen, on 6th May I was asked to give a short introduction to Julia at the Infomath seminar series at Sorbonne Université. While virtual seminars certainly don't share the same spirit as in-person ones do, the ability to quickly …

read more# Talk at Lüchow group seminar at RWTH

On 5th May I was invited to present a short summary of my research at the local theoretical chemistry research group of Prof. Dr. Arne Lüchow at RWTH Aachen. Because I wanted to give a broad overview of topics that I worked on over the past few years, I did …

read more# DFTK: 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 more# Thoughts on initial guess methods for DFT

On Thursday I gave a brief talk in our weekly ACED differentiate group meeting about initial guess methods for starting self-consistent field calculations in methods such as density-functional theory. For preparing the talk I did a little digging into both the standard approaches used by many molecular and solid-state codes …

read more# A novel black-box preconditioning strategy for high-throughput density-functional 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 more# CESMIX TST meeting: DFTK.jl: A multidisciplinary Julia code for density-functional theory development

These past two days I have participated in the Tri-Lab 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 more# High-throughput density-functional 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 density-functional theory (DFT), I chose …

read more# Challenges and prospects of a posteriori error estimation in density-functional 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 Kohn-Sham problems and so I decided to use the opportunity to give a …

read more# Moansi: Inhomogeneous preconditioning for density-functional 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 more# Faraday Discussions: New horizons in density functional theory

Following the submission of our paper on a posteriori error estimation in the Kohn-Sham 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 more# DFTK: 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 real-life conference the organisers did a very …

read more# SCF 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 more# 1st 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

read more*N*-body problems in chemistry an physics, the about 80 participants came from a broad background ranging from quantum …# 36c3: Getting to know Julia session

At this year's 36th Chaos Communication Congress in Leipzig, I signed up to give a short introductory workshop for Julia. To my surprise the room was completely packed yesterday, even though the meeting was scheduled for 11am on day 4 ... Everyone at the session was extremely engaged and packaged with …

read more# Introduction to Julia session at 36c3

If you missed the Julia day at Jussieu in Paris last week, but still want to get to know the programming language Julia a little, have no fear: I'll be doing an introductory Julia session at the 36th Chaos Communication Congress in Leipzig this year (on

read more**day 4, 11am**, so …# Talk in Toulouse: adcc and DFTK

A few weeks ago on 21st and 22nd November of this year Pierre-Francois 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 more# JuliaParis: 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 more# 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 more# Modern software-development 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 …

read more# Coulomb Sturmian basis functions in electronic structure theory

Earlier this month, on 3rd of May, I was invited for a day to the Laboratoire de Physique et Chimie Théoriques of the Université de Lorraine in Metz. Unlike my earlier stay in Metz stay, during the MES conference, last August, I did not manage to enjoy this beautiful city …

read more# Julia lightning talk

Yesterday I gave a short lightning talk at the Inria Devmeetup about Julia. My intention was to show a few of the design aspects of this rather recent programming language and motivated from my experiences in my current PostDoc project at the MATHERIALS team hint at interesting ongoing developments. For …

read more# Coulomb Sturmian basis functions in electronic structure theory

After my first Coulomb Sturmian-related talk at the LCT last November, I was approached by Julien Toulouse and asked whether I could give another talk providing a little more insight into Coulomb Sturmians and their potential.

A few weeks ago, on 29th March, it was thus about time for a …

read more# Design of the molsturm quantum-chemistry framework

A few weeks ago, on 23rd November, I was invited to speak at the mathematics and chemistry seminar (GdT mathématiques et chimie) at Sorbonne Université in Paris. This seminar is a joint meeting of theoretical chemists and mathematicians from the LJLL (Laboratoire Jacques-Louis Lions) and the LCT (Laboratoire de Chimie …

read more# Simulating chemistry: Enabling novel approaches for modelling the electronic structure of molecules

Last week Wednesday I was invited to present my research in front of a bunch of young researchers from the Heidelberg Laureate Forum visiting our institute. Whilst I would have loved to attend the full week of the forum, I am happy that in this way I was able to …

read more# Franco-German Workshop 2018: Open problems related to the algebraic-diagrammatic construction scheme

In some of my recent projects, e.g. the PE-ADC paper, I got a little more into method development surrounding the algebraic-diagrammatic construction scheme (ADC). Even though quite a few people from the Dreuw group in Heidelberg are involved with ADC development and we have regular talks on ADC, I …

read more# MRMCD18: Pitfalls for performance: Latencies to keep in mind

This weekend I attended the MRMCD18 in Darmstadt, which is one of the many chaos events where a few hundred people interested in computer science, hacking, making, politics and society gather for a weekend of talks, coding and discussion. Having participated in this event regularly in the past few years …

read more# MES 2018 in Metz: molsturm Towards quantum-chemical method development for arbitrary basis functions

Currently I am attending the Molecular Electronic Structure 2018 conference in Metz, an electronic-structure theory conference intended for researchers working on novel methodologies, such as explicit correlation, density matrix theory, stochastic approaches or on discretisation techniques going beyond Gaussian-type orbitals.

Especially the latter aspect fits well to the kind of …

read more# Aachen: Beyond Gaussian-type orbitals

From Monday till Wednesday this week I was invited to the computational mathematics research group of Prof. Dr. Benjamin Stamm at the RWTH Aachen University. In retrospect I am very thankful for the invitation, since the three days turned out to be filled with fruitful discussions, scientific exchange and brainstorming …

read more# Oberwolfach workshop: Mathematical Methods in Quantum Chemistry

Last week I was invited to the Mathematical Research Institute Oberwolfach (Mathematisches Forschungsinstitut Oberwolfach) for a workshop about Mathematical Methods in Quantum Chemistry. I am really grateful to the organisers Eric Cancès, Gero Friesecke, Trygve Helgaker and Lin Lin for asking me to join this meeting as it turned out …

read more# Annual Colloquium 2017: Introduction to Bohrium

Last Thursday the PhDs of my graduate school gathered again for our self-organised mini conference, named Annual Colloquium. Having organised this event myself as well a couple of years back, I had rather mixed feelings this time, since I most likely not be around in Heidelberg for another AC.

For …

read more# Lazy matrices talk from the IWR school 2017

As mentioned in a previous post on this matter last month, from 2nd to 6th October, the IWR hosted the school Mathematical Methods for Quantum Chemistry, which I co-organised together with my supervisors Andreas Dreuw and Guido Kanschat as well as the head of my graduate school Michael Winckler.

From …

read more# Coulomb-Sturmians and molsturm

Yesterday I gave a talk at our annual group retreat at the Darmstädter Haus in Hirschegg, Kleinwalsertal. For this talk I expanded the slides from my lazy matrix talk in Kiel, incorporating a few of the more recent Coulomb-Sturmian results I obtained.

Most importantly I added a few slides to …

read more# [c¼h] Parallelised numerics in Python: An introduction to Bohrium

Thursday a week ago I gave a brief introductory talk in our Heidelberg Chaostreff about the Bohrium project. Especially after the HPC day at the Niels Bohr Institute during my recent visit to Copenhagen, I became rather enthusiastic about Bohrium and wanted to pass on some of my experiences.

The …

read more# Lazy matrices in quantum chemistry

On my way back from Copenhagen last Thursday I stopped in Kiel to visit Henrik Larsson and some other people from last year's Deutsche Schülerakademie in Grovesmühle.

Henrik is doing his PhD at the group of Prof. Bernd Hartke and so I took the opportunity and gave a short talk …

read more# HPC day at Niels Bohr Institute

# The design of molsturm

Yesterday I was invited to the give a talk at the group seminar of Prof. Thomas Kühne at the University of Paderborn. I was really happy about this invitation, since this gave me a great opportunity to talk about the recent direction my PhD has taken.

Motivated from the problems …

read more# [c¼h] Testen mit Rapidcheck und Catch

Last Thursday, I gave another short talk at the Heidelberg Chaostreff NoName e.V. This time I talked about writing tests in

`C++`

using the testing libraries rapidcheck and Catch.In the talk I presented some ideas how to incorporate

read more*property-based testing*into test suites for`C++`

programs. The idea …# [c¼h] Einführung in die Elektronenstrukturtheorie

The week before my bash scripting course I gave another short talk for the weekly meeting of the Heidelberg Chaostreff NoName e.V. Unlike last time the talk was not concerned with a traditional "Hacker" topic, but much rather I tried to give a brief introduction into my own research …

read more# A short return to Cambridge

About two weeks ago, on Friday the 13th of March, I was invited back to the Chemistry Department at the University of Cambridge. As part of their Theoretical Chemistry Informal Seminar talk series I was asked to give a short talk (Abstract) about my current research. Needless to say that …

read more# [c¼h] Härtere Crypto für unsere Services

Last Thursday I gave a talk (in German) in our local Chaostreff in Heidelberg — the NoName e.V. The main topic was to introduce the various cryptographic algorithms used in modern cryptography and to give practical advice how to improve the default configuration even further. The talk mainly focuses on …

read more# Annual Colloquium 2014

Last Monday and Tuesday this year's most important event of the HGS Mathcomp (my graduate school) took place — the Annual Colloquium. Being part of the organising committee we stepped into the footsteps of the previous ACs and planned it as a short two-day conference with graduate students presenting their project …

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