, 1 min read
1. The post Hosting Static Content with GitLab was mentioned on Hacker News and this site experienced a heavy increase in accesses. Neither PHP, nor NGINX, nor the ISP experienced any problems. Nevertheless, I had never before seen such a stark rise in accesses to this website. The Slashdot effect…
, 15 min read
1. Notation 2. Example Runge-Kutta methods 3. Local discretization error 4. Order condition 5. Power series expansion for global error 6. Cauchy product formula 7. Recursive calculation of the order condition Below text is based on the results in Peter Albrecht: "A New Theoretical Approach…
, 2 min read
I wrote about hosting static sites on various platforms: Hosting Static Content with surge.sh Hosting Static Content with now.sh, now.sh renamed themself to vercel.app Hosting Static Content with netlify.app Hosting Static Content with Cloudflare Hosting Static Content with Neocities Hosting…
, 2 min read
I wrote about hosting static sites on various platforms: Hosting Static Content with surge.sh Hosting Static Content with now.sh, now.sh renamed themself to vercel.app Hosting Static Content with netlify.app Hosting Static Content with Cloudflare Hosting Static Content with Neocities GitLab…
, 57 min read
1. Konsistenz, Konsistenzordnung und Fehlerkonstanten 2. Die Anwendung linearer Mehrschrittverfahren bei DAE 3. Mehrere Charakterisierungen der Konsistenzordnung 4. Die erste Dahlquist-Barriere 5. Die zweite Dahlquist-Barriere 6. Annullierte Dominanz und Totalannullation 7. Das $n$-dimensionale…
, 17 min read
1. Semistabilitätsfunktionale in Matrixdarstellung 2. Bemerkungen zum Spijkerschen Stabilitätsfunktional 1. Semistabilitätsfunktionale in Matrixdarstellung Mit Ausnahme der Booleschen Algebra wird keine Theorie in der Mathematik universeller benutzt als die lineare Algeba. Es gibt kaum eine…
, 19 min read
1. Das modifizierte Newton-Verfahren und Spezialisierungen 2. Die Divergenzsätze von Hughes Hallett 3. Die Experimente von Byrne/Hindmarsh/Jackson/Brown Einer der ganz zentralen Bestandteile eines Programmes, basierend auf Verfahren mit impliziten Stufen, ist die Auflösung der…
, 58 min read
1. Einführung und grundlegende Begriffe 2. Die Lemmata von Gronwall 3. Notation und Darstellungssatz für Differenzengleichungen 4. Stabilitätsfunktionale für feste Schrittweiten 5. Projektorstabilitätsfunktionale 6. Nichtäquidistante Gitter 7. Die Eigenwerte gewisser tridiagonaler…
, 23 min read
1. Konditionszahlen von Matrizen 2. Elementare Zeilen- und Spaltenoperationen 3. Die $LU$-Zerlegung 4. Die Gauß-Elimination Bei jedem Iterationsschritt eines Newton-Raphson-Verfahrens, bzw. bei jeder Aktualisierung der Iterationsmatrix beim Newton-Kantorovich Iterationsverfahren, fällt die…
, 6 min read
1. Projektor Sei eine lineare Mannigfaltigkeit ${\cal M}\subseteq\mathbb{C}^n$ aufgespannt durch die $s$ linear unabhängigen Vektoren $a_1,\ldots,a_s\in\mathbb{C}^n$. Sei $A=(a_1,\ldots,a_s)\in\mathbb{C}^{n\times s}$. Es gilt $$ % Mehrfache Indizes für Minoren: % #1: Anzahl der Indizes, #2:…
, 2 min read
I turned 60 this year. I had written a similar post ten years ago: Turning 50 - Now what? What has happened in the last ten years? The last time I wrote: I am married and have three children. All three children show interest in society and technology, and will likely find their way through life.…
, 6 min read
This blog offered to switch betwen light and dark mode. But this choice was not stored anywhere. So any page you clicked on, you had to choose dark mode again. Now I store this choice in localStorage on the client. While cookies could also be used for storing this choice, they are not needed for…
, 1 min read
I stumbled on below error message from the IBM COBOL compiler for mainframe: IGYRC5108-U COBOL COMPILER TERMINATING: UNCORRECTABLE PROGRAM INTERRUPT CONDITION. The COBOL program was not fully compiled but compilation stopped midway. Further messages from the compile run: PROGRAM CHECK,…
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I am now a member of the 1MB club. The members must have websites with size below 1 MB. This new membership is not surprising as I am already a member of the two clubs: Member of 512KB club Member of 250KB club This 1MB club has 781 members as of today. Becoming member there is by using: git…
, 4 min read
In the previous post Example Theme for Simplified Saaze: Wendt I demonstrated the transition from a website using WordPress to Simplified Saaze. This very blog, which you are reading right now, also uses Simplified Saaze. his post shows how much better performance-wise this transition was. The…
, 12 min read
Another theme for Simplified Saaze called "Wendt". You can inspect it here. It offers below features: Responsive with media breaks for large and small screens, and for printing. Top menu with submenus. Two column using CSS grid, "Holy Grail Layout". Multiple blogs: Each…
, 5 min read
1. Task at hand. COBOL programs reads UNIX timestamps as input. Output should be the values of year, month, day, hour, minutes, seconds. In C this is just gmtime(). gmtime accepts time_t and produces struct tm: struct tm *gmtime(const time_t *timep); On mainframe, however, it is sometimes a little…
, 7 min read
1. Task at hand. Install H2O web-server on Arch Linux. H2O is a web-server written by Kazuho Oku et al. It supports: HTTP/1 and HTTP/1.1, HTTP/2, HTTP/3 ("QUIC"), FastCGI, therefore PHP-FPM, Reverse proxy, Builtin mruby, though, that crashes. In benchmarks it ranks at the top…
, 2 min read
In the old UNIX days the core file was written where the offending program was started. The only prerequisite was that there was no limit imposed. Limits can be checked by $ ulimit -a -t: cpu time (seconds) unlimited -f: file size (blocks) unlimited -d: data seg size…
, 4 min read
9th April is CSS Naked Day. A day where you do not use CSS on your web-site. In 2024 I participate in this day, i.e., I will deactivate the CSS on this blog. From the CSS Naked Day: The idea behind CSS Naked Day is to promote web standards. Plain and simple. This includes proper use of HTML,…