Similar to most people in their second PostDoc a considerable chunk of time in the past year has been devoted to job hunting, i.e. writing applications, preparing and attending interviews for junior research group positions. As the year is closing I am finally able to make a positive announcement …read more
The goal of quantum-chemical calculations is the simulation of materials and molecules. In density-functional theory (DFT) the first step along this line is obtaining the electron density minimising an energy functional. However, since energies and the density are usually not very tractable quantities in an experimental setup, comparison to experiment …read more
(Cross-post from our report published in the Psi-k blog)
From 20th until 24th June 2022 I co-organised a workshop on the theme of Error control in first-principles modelling at the CECAM Headquarters in Lausanne (workshop website). For one week the workshop unified like-minded researchers from a range of communities, including …read more
Last Thursday and Friday (17/18 February) I taught an introductory course to the Julia programming language. The course took place in virtual format and to my great surprise around 90 people from all over the world ended up joining. Luckily I had a small support team consisting of Gaspard …read more
About two weeks ago, from 10 till 13 Jan 2022 I was at the annual meeting of the French research group on many-body phaenomena, the GDR nbody. Originally scheduled to take place in person in Toulouse the Corona-related developments unfortunately caused the organisers to switch to a virtual event on …read more
A quick teaser to some workshops I will organise next year.
17/18 Feb 2022: Introduction to the Julia programming language (virtual).
In two half-day sessions I will provide a concise overview of the Julia programming language and offer to get some hands-on practice. The selection of exercises and small …
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 more
The simulation of quantum spin models is an actively researched field. Albeit rather basic these many-body systems are inherently strongly correlated and as such feature a rich variety of phaenomena including involved patterns of ordering / discordering, topological order or varieties of phase changes. Furthermore these models often provide a good …read more
As part of my previous work on the adcc code for computational spectroscopy based on the algebraic-diagrammatic construction (ADC), we also integrated the package with QCEngine. This package aims at integrating different quantum-chemistry codes under a common interface for end users, which is an effort I fully support. Recently the …read more
In an ongoing effort with Antoine Levitt our aim is to develop reliable density-functional theory (DFT) methods for computational materials design. Recently we looked into a strategy to automatically select the damping parameter for the self-consistent field iterations (SCF). Our adaptive damping approach is based on a theoretically sound quadratic …read more
About two years ago I integrated my open-source ctx library into the Q-Chem quantum-chemistry software suite. Quicklyread more
ctxbecame part of the core stack for managing computational results inside Q-Chem. In particular inside the
adcmanmodules, which are responsible for most of the coupled-cluster and algebraic-diagrammatic construction methods …
The second event I co-organised at this year's JuliaCon (see this article for the other) was a Birds of Feather (BoF) discussion session titled Building a Chemistry and Materials Science Ecosystem in Julia. In this session Rachel Kurchin and I wanted to gather the various stakeholders working on Julia codes …read more
From 13th July till 30th July this year's JuliaCon finally took place virtually. The first week (13th till 27th) hosted a number of three-hour live-streamed 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 more
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
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
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
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
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
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
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 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
This week I started my new position as a postdocotoral researcher at the Applied and Computational Mathematics (ACoM) research lab at RWTH Aachen University. The lab consists of two interdisciplinary research groups, namely the group of Prof. Dr. Manuel Torrilhon, who works on the mathematical modelling and simulation of technical …read more
A bit over a year ago we published our adcc code. In this work the aim was to develop a toolkit for computational spectroscopy methods focused on rapid development and interactive hands-on usage (see the blog article for details). Our target back then was to simplify method development involving the …read more
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
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
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
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
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
For the past half a year or so Antoine Levitt and myself have been looking at a particular tricky busyness for solid-state density-functional theory (DFT) calculations, namely how to design efficient self-consistent field (SCF) schemes for large inhomogeneous systems. I have already previously reported on this matter in a short …read more
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
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
Since the publication of the adcc paper a few months back, there are a few updates to report briefly:
- adcc can now be interactively tried in the browser at try.adc-connect.org using the infrastructure from the binder project.
- Binary installation of adcc is now available via conda for Linux …
After only a few months of publishing our adcc paper, which introduces the novel algebraic-diagrammatic construction (ADC) code adcc, the package has already found mention in a number of related articles. One example is a manuscript on updates in the Psi4 quantum chemistry package, which features adcc as one of …read more
After about a year of work on the density-functional toolkit (DFTK) we finally started using the code for some new science. Given the mathematics background of the CERMICS the first two DFTK-related articles were not so much about large-scale applications, but rather deal some fundamental questions of Kohn-Sham density-functional theory …read more
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 N-body problems in chemistry an physics, the about 80 participants came from a broad background ranging from quantum …read more
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
As part of my research stay at the Matherials team of ENPC Paris Tech and Inria I have been developing the density-functional 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 more
Over the part year or so a side project I have been working off and on has been the adcc code. This python module allows to perform excited states calculation for simulating molecular spectra based on algebraic-diagrammatic construction (ADC) methods. The speciality of the adcc code is that (a) multiple …read more
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
A quick teaser for some Julia-related 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 meet-up of Paris. We want to gather the people in and around Paris, who are interested in …
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
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
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
Last week I started my new position as a postdoctoral fellow at the MATHERIALS team of the Centre d'Enseignement et de Recherche en Mathématiques et Calcul Scientifique (CERMICS) laboratory and Inria Paris with an additional affiliation to the Institut des Sciences du Calcul et des Données at Sorbonne Université. As …read more
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
This week we submitted a paper related to our ongoing work regarding the use of Coulomb Sturmian basis functions in electronic structure theory. Given the recent progress, which has been made with regards to the evaluation of molecular integrals based on these exponential-type functions, molecular calculations based on Coulomb Sturmians …read more
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
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
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
Yesterday the journal of chemical theory and computation accepted our manuscript titled Polarizable Embedding Combined with the Algebraic Diagrammatic Construction: Tackling Excited States in Biomolecular Systems. In this work we describe the combination of the polarisable embedding (PE) scheme for including environmental effects with the algebraic-diagrammatic construction (ADC) approach.
The …read more
Last week from 18th till 23rd June I attended the 16th International Congress of Quantum Chemistry (ICQC) in Menton, France. Apart from the absolutely stunning scenery at the French Riviera as well as the historic conference building, the conference was a great opportunity to meet up and discuss with people …read more
Last week we submitted the molsturm design paper titled Towards quantum-chemical method development for arbitrary basis functions. This manuscript is a condensed summary of the arguments about design and implementation of a basis-function independent self-consistent field scheme (SCF) already presented in my PhD thesis.
Our approach to a basis-function-independent electronic …read more
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
Finally, after quite some years of work I have successfully defended my PhD thesis with the title Development of a modular quantum-chemistry framework for the investigation of novel basis functions on 22nd May. An electronic version of the text has now been published online.
To make the topic of my …read more
As announced in my previous post about the Oberwolfach workshop on Mathematical Methods in Quantum Chemistry, the proceedings of each Oberwolfach workshop are published in the form of an article in the Oberwolfach reports. For this purpose each speaker is asked for an extended abstract summarising the content of his …read more
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
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
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
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
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
From 2nd to 6th October 2017 the IWR hosts the school Mathematical Methods for Quantum Chemistry, which aims at shining some light into the simulation of quantum chemical problems and their mathematical properties. I am very happy to be part of the organising committee for this school, especially since I …read more
In the past couple of days I hacked together a small Python script, which searches through the EMSL basis set exchange library of Gaussian basis sets via the commandline.
Unlike the webinterface it allows to useread more
grep-like regular expressions for matching the names and descriptions of the basis sets …
In the talk I presented some ideas how to incorporate property-based testing into test suites forread more
C++programs. The idea …
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
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
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 …read more
In January I officially started my PhD in the Theoretical Chemistry group of Prof. Dr. Andreas Dreuw at the Interdisziplinäres Zentrum für wissenschaftliches Rechnen of the Ruprecht-Karls-Universität Heidelberg. The principle aim of the project is to replace the common formalism of using atom-centered basis functions (e.g. Gaussian atomic orbitals …read more
Especially for server's which are required to run 24/7 it is absolutely crucial that one stays updated on the machine's status. E.g. using programs like theread more
smartddaemon of smartmontools provides a good method to detect ageing hard disk long before failures actually occur. Like many other …
Setting up a SOCKS Proxy using ssh
Port forwarding in ssh is really great. Next to local and remote forwarding there is also dynamic port forwarding that essentially turns the ssh server into a SOCKS Proxy server. This means that you can actually route all the traffic of a local …read more
Last week I updated the OS on my SSD-only laptop to Debian Jessie and I thought that would be a good opportunity to finally set up full-disk encryption(FDE) on that machine as well. Against my usual policy I did not do so initially fearing the possible performance drawbacks from …read more