Posts in Software Engineering

Announcing NKP 0.1: Static Analysis for Kotlin Projects

I’m excited to share the first MVP release of NKP (aNalysis of Kotlin Programs), a command-line tool for analyzing Kotlin codebases and uncovering architectural insights.

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Nov 01, 2025 Read more arrow_forward

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Java in the Technology Radar (JavaSpektrum)

I’ve written a new article for JavaSpektrum: “Java im Technology Radar – Totgesagte leben länger”. The piece looks back at Java’s journey through the eyes of the Thoughtworks Technology Radar...

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Sep 03, 2025 Read more arrow_forward

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Structured Concurrency in Java 24 (JavaSpektrum)

I’ve written an article for JavaSpektrum 2/2025 about Structured Concurrency in Java 24. The article covers JEP 499, Java’s fourth preview of Structured Concurrency, which aims to make concurrent programming...

software-engineering java concurrency article jvm parallelism architecture

Mar 31, 2025 Read more arrow_forward

Who Ensures Quality in the Scaled Agile Framework (SAFe)?

As an external consultant in an Enabling Team for Cloud Architecture, I supported several teams and noticed that software development quality was lacking. This surprised me because the client was...

software-engineering agile quality-assurance

May 31, 2024 Read more arrow_forward

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Test driven development of concurrent programs in Kotlin at KKon 2022

Concurrent and asynchronous applications can be written in Kotlin with coroutines in a precise and structured way. Unfortunately, concurrency often increases the complexity and it is difficult to create bug-free...

software-engineering kotlin parallelism concurrency talk slides quality-assurance

Sep 13, 2022 Read more arrow_forward

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Coroutines in Kotlin at KKon 2021 Warmup

In my talk “Nebenläufigkeit mit Koroutinen strukturieren” at the KKon 2021 Warmup I explained how to structure and organize concurrent programs with coroutines in Kotlin.

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Apr 23, 2021 Read more arrow_forward

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The Ray Tracer Challenge in Kotlin

During the chrismas holiday I started a new ray tracer in Kotlin while following the book “The Ray Tracer Challenge.

software-engineering kotlin graphics

Jan 10, 2021 Read more arrow_forward

Update of my website to Bootstrap 5

I updated my website so that it looks new and shiny and provides faster and easier access.

software-engineering web

Dec 29, 2020 Read more arrow_forward

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Refactoring with the Mikado Method

At a client of ThoughtWorks I gave a talk about refactoring in line with the book “Mikado Method”. The book describes a method to plan and perform non-trivial refactorings of...

software-engineering tdd talk slides clean-code

Apr 02, 2020 Read more arrow_forward

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A short introduction to Kotlin

At a client of ThoughtWorks I gave a talk about the advantages of Kotlin.

software-engineering kotlin jvm talk slides

Mar 04, 2020 Read more arrow_forward

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Plain react, hooks and/or Redux

At a client of ThoughtWorks I gave a short presentation about three different ways of state management in React.

software-engineering talk slides javascript front-end

Mar 04, 2020 Read more arrow_forward

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Coroutines in Kotlin and Go in iX Developer - "Weniger warten, asynchron arbeiten"

In the article “Verteilte Systeme: weniger warten, asynchron arbeiten” (distributed systems: less waiting, asychronous working) in the german magazine iX Developer Moderne Softwareentwicklung - code(), build(), deploy() I explain the...

software-engineering article kotlin concurrency parallelism golang

Dec 01, 2019 Read more arrow_forward

Migrating a ray tracer from Java and Groovy to Kotlin (part 3)

I continued to work on migrating my ray tracer to Kotlin. Now the scenes can be specified with a Kotlin DSL and all Groovy code is gone.

software-engineering kotlin graphics

May 25, 2019 Read more arrow_forward

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Coroutines in Kotlin and Go on heise Developer

In the article “Weniger warten, asynchron arbeiten” (less waiting, asychronous working) published by heise Developer I explain the theoretical background of coroutines and how to use them in Kotlin and...

software-engineering article kotlin concurrency parallelism golang

May 06, 2019 Read more arrow_forward

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Concurrency in Kotlin with coroutines

Coroutines are a “new” way to handle concurrency on the JVM. I gave an introduction to coroutines in Kotlin at Thoughtworks. This is basically the translation of the german slides....

software-engineering slides talk kotlin concurrency parallelism jvm

Apr 23, 2019 Read more arrow_forward

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Talk about coroutines in Kotlin at the parallel 2019 conference

Coroutines are a “new” way to handle concurrency on the JVM. At the para//el 2019 conference, I gave an introduction to coroutines in Kotlin.

software-engineering slides talk kotlin concurrency parallelism jvm

Feb 21, 2019 Read more arrow_forward

Fusion of object oriented and functional programming

The fusion of Object Oriented Programming (OOP) and Functional Programming (FP) languages has become increasingly popular in recent years, with many programming languages now offering features and constructs from both...

software-engineering kotlin object-functional scala functional-programming

Jan 02, 2019 Read more arrow_forward

Migrating a ray tracer from Java and Groovy to Kotlin (part 2)

I continued to work on migrating my ray tracer to Kotlin.

software-engineering kotlin graphics

Oct 06, 2018 Read more arrow_forward

Migrating a ray tracer from Java and Groovy to Kotlin (part 1)

After reading the wonderful book Kotlin in Action I started to migrate my ray tracer from Java and Groovy to Kotlin.

software-engineering kotlin graphics

Feb 25, 2018 Read more arrow_forward

EuroClojure 2017 in Berlin

In my first project for ThoughtWorks the backend is written in Clojure. Since the project was in Berlin, I visited the EuroClojure 2017 which takes place in Berlin this year,...

software-engineering jvm functional-programming

Jul 22, 2017 Read more arrow_forward

Working for ThoughtWorks

After long considerations i decided to quit being a freelancer and joined ThoughtWorks in Hamburg, Germany.

software-engineering thoughtworks

Feb 01, 2017 Read more arrow_forward

Updated library of geometric algorithms

Today I released an updated version of the library of geometric algorithms.

software-engineering algorithms functional-programming

Nov 22, 2016 Read more arrow_forward

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Visualizing family names with Node, Angular, and D3 for Coding da Vinci Nord 2016

As part of the cultural hackathon Coding da Vinci Nord 2016, I built a web application for the analysis and visualization of the distribution of family names. I used (among...

software-engineering javascript web java data front-end

Nov 10, 2016 Read more arrow_forward

A very good introduction to the best testing framework for the Java platform

In my opinion, the Spock Framework is currently the most convenient testing framework for the Java platform. Since it is built on the Groovy language, it is very expressive.

software-engineering tdd review jvm

Aug 12, 2016 Read more arrow_forward

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Reviewer of Introducing Data Science

I bought the book in early access (MEAP) and decided to help as a reviewer.

software-engineering review

May 31, 2016 Read more arrow_forward

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Ray tracing with Groovy and Java

While I was reading the excellent book by Kevin Suffern "Ray tracing from the ground up", I implemented a ray tracer in Java and wrote a DSL in Groovy, to...

software-engineering groovy java model-driven jvm graphics

Jul 08, 2015 Read more arrow_forward

Covariance and Contravariance in Scala

The topic of covariance and contravariance is explained in many places (including Wikipedia). This post is my attempt to explain it in my own words, using Scala.

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Jul 06, 2015 Read more arrow_forward

Covariance and Contravariance in Scala

I explain "covariance and contravariance" with some simple Scala examples.

software-engineering scala jvm object-functional

Jul 06, 2015 Read more arrow_forward

A very good introduction to Scala

Scala is an important milestone in the fusion of functional and object-oriented programming. This fusion is not yet complete, but rather a “discovery process” that will continue for a few...

software-engineering scala review jvm object-functional

Jun 17, 2015 Read more arrow_forward

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Using Elasticsearch with Spring Boot - Analyzing the emails with Kibana

This is the last part in a series of four. It shows how to analyse the emails with Kibana.

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May 28, 2015 Read more arrow_forward

Using Elasticsearch with Spring Boot - Technical background

This is the third part in a series of four. It explains the technical background.

software-engineering jvm groovy spring

May 27, 2015 Read more arrow_forward

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Using Elasticsearch with Spring Boot - Installation and Usage

This is the second part in a series of four. It shows installation and usage.

software-engineering jvm groovy spring

May 26, 2015 Read more arrow_forward

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Using Elasticsearch with Spring Boot

This article shows how to use Elastiksearch database with Spring Boot. It is the first in a series of four.

software-engineering jvm groovy spring

May 25, 2015 Read more arrow_forward

Measuring traffic on the PCI Express Bus (PCIe)

During my talk at the parallel 2015 conference i was asked how one can measure traffic on the PCI express bus. For multi GPU computing it is very important to...

software-engineering c++

Apr 24, 2015 Read more arrow_forward

OO with JavaScript Excellently Explained

JavaScript has a prototype-based approach to object orientation. This makes it very different from the common object-oriented programming languages, such as Java, C++, and Ruby.

software-engineering javascript review

Apr 04, 2015 Read more arrow_forward

Trying out next-gen JavaScript now with ECMAScript 6

With Babel you can test many features of the upcoming next version of JavaScript called ECMAScript 6 now.

software-engineering javascript

Apr 04, 2015 Read more arrow_forward

Examples for parallelism: ray tracer

I wanted to learn some frameworks for parallel computing and i decided to implement a simple ray tracer as a "visual benchmark".

software-engineering c++ java graphics parallelism concurrency

Mar 03, 2015 Read more arrow_forward

Advanced 'git'

I have been using git for a few years now, but I wanted to gain more background knowledge and learn about more complex workflows. The book “Git in Practice” succeeded...

software-engineering review

Jan 29, 2015 Read more arrow_forward

Too Short an Introduction to PaaS

“Understanding PaaS” is a very small booklet about the basics of cloud computing. It can be read to get a very quick introduction to the topic. It is written more...

software-engineering review

Jan 27, 2015 Read more arrow_forward

An Almost Definitive Introduction to MongoDB

“MongoDB: The Definitive Guide” is a well-rounded overview of MongoDB from both a developer and a DBA perspective. At least as far as I can tell as a MongoDB beginner...

software-engineering review data javascript

Jan 16, 2015 Read more arrow_forward

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Reviewer of Java 8 in Action

I bought the book in early access (MEAP) and decided to help as a reviewer.

software-engineering review java scala jvm object-functional

Dec 17, 2014 Read more arrow_forward

“Sophisticated” JavaScript

If there is such a thing as “sophisticated” literature, then there is now also “sophisticated” code. “If Hemingway Wrote JavaScript” contains many funny and educational examples.

software-engineering javascript review

Dec 17, 2014 Read more arrow_forward

New Edition Required: Good Book, but Unfortunately Outdated

“Using OpenMP” is a good introduction and contains a few good performance tips.

software-engineering c++ parallelism concurrency review

Mar 20, 2014 Read more arrow_forward

Currently the Best Presentation of Patterns for Shared Mutability

If you want to bring a bit of systematism to your parallel programming skills, “Structured Parallel Programming: Patterns for Efficient Computation” is the book to start with.

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Mar 11, 2014 Read more arrow_forward

Recommended Classic in a New Edition

I had already read the second edition back in 1992. Since then, a lot has changed for the better, both with C++ and this “classic.”

software-engineering c++ review

Feb 25, 2014 Read more arrow_forward

A Good Overview of C++ 11

In this small book, the creator of C++ provides an overview of the new features in C++ 11 and the STL.

software-engineering c++ review

Feb 11, 2014 Read more arrow_forward

Good Overview and Introduction

Anyone wanting to learn Grails cannot ignore “The Definitive Guide to Grails 2”.

software-engineering review web jvm groovy

Nov 11, 2013 Read more arrow_forward

A lot of Haskell, too little functional programming

I read “Learn You a Haskell for Great Good” to refresh my knowledge of Haskell. During my studies in the nineties, I was an enthusiastic functional programmer. I wrote my...

software-engineering functional-programming review

Oct 15, 2013 Read more arrow_forward

Tips of very varying quality

The book “97 Things Every Programmer Should Know” consists of 97 sections by different authors regarding frequently occurring questions in software development.

software-engineering review

Jul 30, 2013 Read more arrow_forward

First Steps in API Design with C++

“API Design for C++” is an excellent introduction to the implementation of APIs with C++.

software-engineering review c++

Jul 07, 2012 Read more arrow_forward

Recommended as a Reference Work

“Patterns for Parallel Programming” is an important work for ‘parallel programmers’.

software-engineering review parallelism concurrency

Feb 23, 2012 Read more arrow_forward

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Slides: 'Introduction to Parallel Computing'

These slides are for a course about parallel computing.

software-engineering slides parallelism concurrency

Dec 12, 2011 Read more arrow_forward

Good introduction to jQuery and its ecosystem

“Head First jQuery” is written in the “Head First” style and is aimed at beginners and career changers who already have a basic knowledge of HTML and CSS, as well...

software-engineering review web

Dec 06, 2011 Read more arrow_forward

A Concise Introduction and Overview of Spring ROO

The book “Getting Started with Roo” is just over 50 pages long and provides a brief and high-level introduction to using Spring ROO.

software-engineering review jvm

Dec 01, 2011 Read more arrow_forward

Very good in places, unpolished and too brief in others

Programming parallel and concurrent programs with shared memory and threads is complicated and very error-prone. Approaches such as Software Transactional Memory (STM), message-passing architectures, and actor models have been developed...

software-engineering parallelism concurrency jvm review object-functional

Dec 01, 2011 Read more arrow_forward

Only for 'Thread Monkeys'

With the title “The Art of Concurrency”, high expectations are set that are not met. The subtitle “A Thread Monkey’s Guide to Writing Parallel Applications” is more fitting for the...

software-engineering review parallelism concurrency c++

Nov 15, 2011 Read more arrow_forward

This book will help you become a better programmer

“This book will help you become a better programmer” is the first sentence in the introduction of the book “Der Pragmatische Programmierer”. And I believe that it is true.

software-engineering review agile

Nov 04, 2011 Read more arrow_forward

Excellent Book for Beginners and Advanced Readers

“Ray Tracing from the Ground Up” is an excellent book for beginners and advanced readers. You can tell that the author has spent many years working on the subject and...

software-engineering review graphics c++

Jan 10, 2011 Read more arrow_forward

Using Scala and TestNG with Gradle

During the christmas holidays i tried out Scala and TestNG with Gradle.

software-engineering scala tdd jvm object-functional

Dec 30, 2010 Read more arrow_forward

Sony Alienates Early PlayStation 3 Fans

On April 1st, Sony released an update for the PlayStation 3 that discontinued support for Linux. This move angered many, sparking intense reactions and discussions.

software-engineering parallelism concurrency

Apr 07, 2010 Read more arrow_forward

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Training: Test-Driven Development with JUnit 4

This training teaches test-driven development with a focus on JUnit 4. Other frameworks such as JUnit 3 and TestNG are briefly introduced as well (as of 2009).

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Oct 11, 2009 Read more arrow_forward

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Training: Subversion

This training on Subversion covers practical version control workflows.

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Oct 10, 2009 Read more arrow_forward

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Training: Ant in Depth

Apache Ant offers a lot of capabilities that many teams never end up using. This training dives into Ant’s more advanced features (as of 2009).

software-engineering slides jvm

Oct 09, 2009 Read more arrow_forward

Groovy, EMF and UML2

I wrote the Groovy EMF builder and the Groovy UML2 builder. These tools use the builder concept of the programming language Groovy to ease the processing of Eclipse Modelling Framework...

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Aug 01, 2009 Read more arrow_forward

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Hyper-Threading with the Intel Core i7

I have got a new computer. As alway i build it myself. How much faster is it?

software-engineering parallelism concurrency c++

Jun 14, 2009 Read more arrow_forward

Parallelization with Haskell - Easy as can be

The functional programming language Haskell provides a very easy way of parallelization.

software-engineering parallelism concurrency functional-programming

Jun 07, 2009 Read more arrow_forward

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Real-Time RayTracer running on Intel Core i7

I tested my ray tracer on Intel Core i7 920 @2.67 MHz.

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Jun 04, 2009 Read more arrow_forward

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Real-Time RayTracer running on Core 2 Duo

I tested my ray tracer on my Mac Book Pro.

software-engineering parallelism concurrency graphics c++

May 24, 2009 Read more arrow_forward

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Parallelization with the Cell Broadband Engine

I wanted to learn about the cell broadband engine in the Playstation 3 and wrote a parallel ray tracer for it.

software-engineering parallelism concurrency graphics c++

May 19, 2009 Read more arrow_forward

New version of the library of geometric algorithms in Haskell

Almost 10 years after the initial release, i released an updated version of the library of geometric algorithms in Haskell. It now builds with Cabal and requires the Glasgow Haskell...

software-engineering functional-programming algorithms

Feb 27, 2008 Read more arrow_forward

Memoization in Groovy with a Decorator

Memoization is a well known optimization technique to avoid repeated calculations. With dynamic programming languages like Groovy it is possible to extend the behaviour of an already exisiting class at...

software-engineering groovy jvm

Feb 27, 2008 Read more arrow_forward

Accessing EMF models with JRuby

JRuby provides access to Java packages, so it is possible to use packages created with the Eclipse Modeling Framework (EMF).

software-engineering ruby model-driven jvm

Jan 27, 2008 Read more arrow_forward

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Writing Eclipse plugins with Groovy

Writing plugins for Eclipse with other languages than Java is not officially supported, but there is a way to write an Eclipse plugin with Groovy only.

software-engineering groovy eclipse jvm java

Jan 17, 2008 Read more arrow_forward

Eclipse BugDays 2007

I participated at Eclipse BugDays in July, August, September, October, and November 2007 and helped debugging the Eclipse projects JDT, PDE/UI, and ECF.

software-engineering eclipse jvm java

Dec 01, 2007 Read more arrow_forward

Using UML2 with Groovy

The UML2 project provides an EMF based implementation of the UML 2.x metamodel in Java. With the EMFBuilder it is possible to create and process UML2 models.

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Nov 29, 2007 Read more arrow_forward

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Rapid Application Development with Groovy

While i was cleaning up my hard disk on my Linux in 2007, i needed a program that displays the disk usage graphically. I didn't find a suitable one on...

software-engineering groovy jvm parallelism concurrency

Nov 01, 2007 Read more arrow_forward

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Using EMF with Groovy

This article shows how Groovy can be used with the Eclipse Modeling Framework (EMF).

software-engineering groovy eclipse model-driven jvm

Oct 22, 2007 Read more arrow_forward

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Editor for the Common Warehouse Metamodel (CWM)

The Common Warehouse Metamodel (CWM) is a standard by the Object Management Group (OMG). The intention of CWM is to define a standard for metadata in Data Warehouses and Business Intelligence applications.

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Oct 01, 2007 Read more arrow_forward

Higher order Markov chains in Ruby - Ruby Quiz #74

Here’s my second solution for the quiz No 74. It generates text with a first or higher order Markov chains. See also the first order version.

software-engineering ruby algorithms

Apr 11, 2006 Read more arrow_forward

Markov chains in Ruby - Ruby Quiz #74

Here’s my solution for the quiz No 74. It generates text with a first order Markov chain.

software-engineering ruby algorithms

Apr 09, 2006 Read more arrow_forward

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Eclipse-Editor for data warehousing metadata with EMF

When i first heard of the Eclipse Modeling Framework (EMF) i got really excited, i tried it out and i wanted to use it.

software-engineering eclipse jvm java model-driven data

Apr 02, 2006 Read more arrow_forward

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Eclipse SQL Editor Plugin

I wanted to find out how hard it is to build a language editor in Eclipse. Back then I didn’t know of any open-source SQL editor (and there wasn’t one...

software-engineering eclipse jvm java

Mar 07, 2006 Read more arrow_forward

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Graphical Editors with Eclipse

Over Christmas 2004, I built an EMF plugin for family trees. Around Easter 2005, I finally found the time to develop a GEF-based editor for it.

software-engineering eclipse jvm java

May 10, 2005 Read more arrow_forward

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Geometric algorithms in Haskell

In my diploma thesis I investigate functional programming and geometric algorithms

software-engineering algorithms functional-programming

Oct 19, 1998 Read more arrow_forward

Dynamic Scheduling in Real-Time Systems

In this seminar paper (1996), written during my graduate studies in computer science, I cover scheduling algorithms for distributed real-time systems.

software-engineering parallelism concurrency algorithms distributed

May 07, 1996 Read more arrow_forward

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Optimal Fast List-Ranking and Prefix Algorithms

A seminar paper on optimal parallel algorithms for prefix sums and list ranking.

software-engineering parallelism concurrency algorithms

Feb 05, 1995 Read more arrow_forward

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Graphics programming in c't

Programming TrueColor graphics with the Diamond Speedstar 24x

software-engineering graphics article

Mar 31, 1993 Read more arrow_forward