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First slide of the talk

Tutorial on Boost.Spirit at C++ User Group Karlsruhe

Posted on 2018-09-12 19:30 by Timo Bingmann at Permlink with 0 Comments. Tags: talk c++ parsing

On September 12th, 2018, I gave another 90min talk with live-coding examples in German at the C++ User Group Karlsruhe in rooms of the Karlsruhe Institute of Technology (KIT).

This time I was asked to present a more advanced topic around C++ and libraries and I chose to present a tutorial on Boost.Spirit.

Boost.Spirit is a parser and generator template meta-programming framework and maybe one of the most crazy and advanced uses of C++. It enables one to write context-free grammars inline as C++ code, which are translated into recursive descent parsers and fully optimized by the compiler.

This powerful framework is however not easy to get started with. I hope my tutorial helps more people to skip the steep learning curve and use Boost.Spirit for securely parsing user input and other structure data.

The tutorial consisted of a set of introduction slides: slides-2018-09-12-Cpp-Meetup.pdf slides-2018-09-12-Cpp-Meetup.pdf. Followed by a live-coding session in German which was recorded by the KIT (see below for the youtube video).

Download slides-2018-09-12-Cpp-Meetup.pdf

The extensive code examples presented in the live coding session are available on this webpage
or on github: https://github.com/bingmann/2018-cpp-spirit-parsing.

The examples can be seen as instructive templates and copy & paste sources for new development. The examples are:

  1. Learn to walk and parse simple integers and lists.
    Parse 5, [5, 42, 69, 256].
  2. Create a parser for a simple arithmetic grammar (and part two).
    Parse 5 + 6 * 9 + 42 and evaluate correctly.
  3. Parse CSV data directly into a C++ struct.
    Parse AAPL;Apple;252.50; into a struct.
  4. Create an abstract syntax tree (AST) from arithmetic (and part two).
    Parse y = 6 * 9 + 42 * x and evaluate with variables.
  5. Ogle some more crazy examples, e.g. how to parse.
    <h1>Example for <b>C++ HTML Parser<b></h1>
    This HTML <b>snippet</b> parser can also interpret
    *Markdown* style and enables additional tags
    to <% invoke("C++", 42) %> functions.

Furthermore, a recording of the live-coding in German is available on Youtube:
https://www.youtube.com/watch?v=gYAheppw73U


Book Cover of Dissertation

Dissertation "Scalable String and Suffix Sorting: Algorithms, Techniques, and Tools"

Posted on 2018-07-03 18:00 by Timo Bingmann at Permlink with 1 Comments. Tags: talk university dissertation frontpage

The road to a Dr. title (PhD in the Anglo-Saxon world) is often long, rough, and twisted. First you have to do original research, produce novel results, publish articles, and then write and ultimately publish a dissertation. Defending your research in the dissertation in front of a panel of professors is one of the final milestones on that journey.

On July 3rd, I successfully defended my dissertation at the Karlsruhe Institute of Technology and the dissertation text has now been published as a book.

Published Dissertation

My final dissertation PDF is available here: dissertation-Bingmann-Scalable-String-and-Suffix-Sorting.pdf dissertation-Bingmann-Scalable-String-and-Suffix-Sorting.pdf.

It has also been published at the KIT library, on arXiv:1808.00963, and finally as a print-on-demand paperback from Amazon.

The published book cover's background shows a list of most common words in the Wikipedia. The words are sorted and their distinguishing prefix is marked in blue. The cover is available as a double-page PDF: dissertation-cover.pdf dissertation-cover.pdf, and as front and back separately: dissertation-cover-front.pdf dissertation-cover-front.pdf and dissertation-cover-back.pdf dissertation-cover-back.pdf.

The LaTeX source code for my dissertation is available for download: dissertation-source.zip dissertation-source.zip (791 KiB). The complete text is in one .tex file, all figures (except the creative commons logo) are generated from the LaTeX code.

Dissertation Defense Presentation

The slides of my presentation during the defense are available for download here: dissertation-defense-slides.pdf dissertation-defense-slides.pdf.

The presentation was only part of the whole defense. My actual slide set also had almost 200 more backup slides, which however were collected from all the other talks already available on this homepage. These backup slides helped greatly in the examination question after the presentation.

Download dissertation-defense-slides.pdf
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TLX Logo

Note about the new tlx library of Advanced C++ Data Structures and Algorithms

Posted on 2018-05-28 18:20 by Timo Bingmann at Permlink with 0 Comments. Tags: c++

Last year on February 19th, I started a new github repository called tlx with the goal of de-duplicating code from three projects: Thrill, STXXL, and a private project. The idea came up after a STXXL code workshop in Frankfurt (fashionably called hackathons nowadays).

Link to library: http://github.com/tlx/tlx and Doxygen Documentation

The first main common pieces of code were:

  1. the fast loser tree implementations from MCSTL by Johannes Singler necessary for efficient multiway merging,
  2. my die() macros for testing and run-time assertions,
  3. a common intrusive reference counter called counting_ptr, and
  4. simple but vital std::string manipulation functions missing from the STL.

The initial reason for tlx to come about was to consolidate all the bug fixes to the loser tree implementations that I had scattered across the three projects. Efficient multiway merging is such a fundamental task and there was no universally available C++ library that implements the tournament tree well.

A long search for an appropriate vacant user account with three letters on github lead to "tlx". This is definitely a good C++ namespace name, but to this day, it is unclear what the letters stand for. Template Libraries for CXX? The missing Library for CXX? Template Library and more eXtensions. Have your pick, someday someone will find a good official expansion.

Since its inception, tlx has grown a lot. Its goal is to consolidate algorithms and data structures from multiple projects. In a sense tlx maybe aims to be the Boost for advanced algorithms. The goals and constraints of tlx are:

  • To have a library of well implemented and tested advanced algorithms and things missing from the C++ STL.
  • Target high modularity with as little dependencies between modules as possible.
  • Zero external dependencies: no additional libraries are required.
  • Only have compile time configuration (no platform dependent checks).
  • Compile on all platforms with C++ -- smartphones, supercomputers, windows, maybe even embedded microcontrollers.
  • Attempt to never break existing interfaces.
  • Warning and bug-freeness on all compilers.
  • Keep overhead down -- small overall size such that is can be included without bloating applications.
  • Collect code only under the Boost license, which one of the most liberal licenses and can be used any project.

Currently, tlx contains

  • The fast tournament (loser) trees from MCSTL by Johannes Singler, with many fixes.
  • A fast intrusive reference counter called CountingPtr, which has considerably less overhead than std::shared_ptr.
  • Efficient and fast multiway merging algorithms from Johannes Singler, which were previously included with gcc. The tlx version has many fixes and is available for clang and MSVC++.
  • Many string manipulation algorithms for std::string.
  • An improved version of my stx-btree implementation, which is basically always a better alternative to std::map (but not std::unordered_map).
  • A copy of siphash for string hashing.
  • Efficient sequential string sorting implementation such as radix sort and multikey quicksort (described in length in my PhD thesis).

And much more, which one can find on the front page of the Doxygen Documentation


First slide of the talk

Presentation "C++ Goodies" at C++ User Group Karlsruhe

Posted on 2017-03-08 00:00 by Timo Bingmann at Permlink with 0 Comments. Tags: talk c++

On March 8th, 2017, I gave a 90min talk in German at the C++ User Group Karlsruhe which consisted mostly of live-coding examples of how to use new C++11/14/17 features in a practical setting. The contents were:

  • Rvalue References and Move Semantics (with Excursions into Lambdas and std::function)
  • Virtual Final Override
  • Variadic Template Parameter (Un-)Packing
  • Random Bits of Thrill

The source code I wrote for the presentation and the slides
are available in a github repository https://github.com/bingmann/2017-cpp-goodies.

Direct link to the slides PDF.

Furthermore, a recording of talk in German is available on Youtube: https://www.youtube.com/watch?v=EvSZHXmXR1M


First slide of the talk

Presentation "Thrill: High-Performance Algorithmic Distributed Batch Data Processing with C++" at IEEE Big Data 2016

Posted on 2016-12-06 16:00 by Timo Bingmann at Permlink with 0 Comments. Tags: talk thrill

Today, I gave a presentation of our paper "Thrill: High-Performance Algorithmic Distributed Batch Data Processing with C++" at the IEEE International Conference on Big Data 2016 in Washington D.C., USA. An extended technical report of our paper is also available on this website or on arXiv.

The slides of the presentation at the IEEE conference are available here:
slides-Thrill-High-Performance-Algorithmic-Distributed-Batch-Data-Processing-with-CPP-TalkAsGiven.pdf slides-Thrill-High-Performance-Algorithmic-Distributed-Batch-Data-Processing-with-CPP-TalkAsGiven.pdf.

Below a longer version of the slides is available for download:
slides-Thrill-High-Performance-Algorithmic-Distributed-Batch-Data-Processing-with-CPP.pdf slides-Thrill-High-Performance-Algorithmic-Distributed-Batch-Data-Processing-with-CPP.pdf.
These slides contain additional figures which are useful to understand the DIA operations in Thrill, along with many extra design slides omitted from shorter talks.

Download slides-Thrill-High-Performance-Algorithmic-Distributed-Batch-Data-Processing-with-CPP.pdf

Abstract

We present the design and a first performance evaluation of Thrill - a prototype of a general purpose big data processing framework with a convenient data-flow style programming interface. Thrill is somewhat similar to Apache Spark and Apache Flink with at least two main differences. First, Thrill is based on C++ which enables performance advantages due to direct native code compilation, a more cache-friendly memory layout, and explicit memory management. In particular, Thrill uses template meta-programming to compile chains of subsequent local operations into a single binary routine without intermediate buffering and with minimal indirections. Second, Thrill uses arrays rather than multisets as its primary data structure which enables additional operations like sorting, prefix sums, window scans, or combining corresponding fields of several arrays (zipping).

We compare Thrill with Apache Spark and Apache Flink using five kernels from the HiBench suite. Thrill is consistently faster and often several times faster than the other frameworks. At the same time, the source codes have a similar level of simplicity and abstraction.


First slide of the talk

Presentation "STXXL and Thrill (Parallel Batch Processing)" at STXXL Workshop in DFG SPP 1736

Posted on 2016-09-21 20:00 by Timo Bingmann at Permlink with 0 Comments. Tags: talk thrill stxxl

Today, I gave a technical presentation comparing STXXL and Project Thrill at the STXXL Workshop organized within the DFG SPP 1736. The main topic of the workshop was to determine the future development course of STXXL, and the biggest question in this regard was how to bring more multi-core parallelization into STXXL. Thrill or an adaptation of its ideas may be the solution to this challenge: 2016-09-21 STXXL and Thrill Slides.pdf 2016-09-21 STXXL and Thrill Slides.pdf.

Download 2016-09-21 STXXL and Thrill Slides.pdf

A figure from the technical report

Thrill: High-Performance Algorithmic Distributed Batch Data Processing with C++

Posted on 2016-08-20 09:54 by Timo Bingmann at Permlink with 0 Comments. Tags: research c++ thrill

Our technical report on "Thrill: High-Performance Algorithmic Distributed Batch Data Processing with C++" is now available on arXiv as 1608.05634 or locally: 1608.05634v1.pdf 1608.05634v1.pdf with source 1608.05634v1.tar.gz 1608.05634v1.tar.gz (780 KiB).

This report is the first technical documentation about our new distributed computing prototype called Thrill. Thrill is written in modern C++14, and open source under the BSD-2 license. More information on Thrill is available from the project homepage.

Thrill's source is available from Github.

Download 1608.05634v1.pdf

Abstract

We present the design and a first performance evaluation of Thrill -- a prototype of a general purpose big data processing framework with a convenient data-flow style programming interface. Thrill is somewhat similar to Apache Spark and Apache Flink with at least two main differences. First, Thrill is based on C++ which enables performance advantages due to direct native code compilation, a more cache-friendly memory layout, and explicit memory management. In particular, Thrill uses template meta-programming to compile chains of subsequent local operations into a single binary routine without intermediate buffering and with minimal indirections. Second, Thrill uses arrays rather than multisets as its primary data structure which enables additional operations like sorting, prefix sums, window scans, or combining corresponding fields of several arrays (zipping).

We compare Thrill with Apache Spark and Apache Flink using five kernels from the HiBench suite. Thrill is consistently faster and often several times faster than the other frameworks. At the same time, the source codes have a similar level of simplicity and abstraction.


Sketch of a edge-split-attach operation, which breaks a unique exchange from e.

"On the Structure of the Graph of Unique Symmetric Base Exchanges of Bispanning Graphs" - Diploma Thesis in Mathematics

Posted on 2016-01-14 18:30 by Timo Bingmann at Permlink with 0 Comments. Tags: maths university frontpage

After a long exhausting period with many interruptions my diploma thesis in mathematics "On the Structure of the Graph of Unique Symmetric Base Exchanges of Bispanning Graphs" is finalized and submitted. The full abstract of the thesis is shown below, and an additional German abstract is available further down the page.

The final version of the thesis is available here: thesis pdf Bingmann-On-the-Structure-of-the-Graph-of-Unique-Symmetric-Base-Exchanges-of-Bispanning-Graphs.pdf, and was also uploaded to arXiv.org as 1601.03526.

The underlying problem discussed in the thesis is best explained using a game on a bispanning graph. You can play the game with this Java Applet or using the Java WebStart Launcher (if the Applet does not work). You play Alice's role and want to flip the colors of all edges in the graph. Bob will try to prevent this from happening.

In addition to the thesis itself, the source code of the accompanying computer program is also available. It was used while preparing the thesis to calculate exchanges graphs and to test many hypothesis about bispanning graphs. The program can enumerate all bispanning graphs and their exchange graphs for small numbers of vertices. See the program page for downloadable lists and PDFs of all bispanning graphs for small numbers of vertices.

Abstract

Bispanning graphs are undirected graphs with an edge set that can be decomposed into two disjoint spanning trees. The operation of symmetrically swapping two edges between the trees, such that the result is a different pair of disjoint spanning trees, is called an edge exchange or a symmetric base exchange. The graph of symmetric base exchanges of a bispanning graph contains a vertex for every valid pair of disjoint spanning trees, and edges between them to represent all possible edge exchanges. We are interested in a restriction of these graphs to only unique symmetric base exchanges, which are edge exchanges wherein selecting one edge leaves only one choice for selecting the other. In this thesis, we discuss the structure of the graph of unique symmetric edge exchanges, and the open question whether these are connected for all bispanning graphs.

This abstract problem can be nicely rephrased into a coloring game with two players: Alice and Bob are given a bispanning graph colored with two disjoint spanning trees, and Alice gets to flip the color of any edge. This creates a cycle in one color and a cut in the other, and Bob must then flip a different edge to repair the constraint that both colors represent disjoint spanning trees. Alice's objective is to invert the color of all edges in the graph, and Bob's to prevent this. We are interested in whether Alice can find a sequence of unique edge exchanges for any bispanning graph, since these leave Bob no choice in which edge to select, hence allowing Alice to win with certainty.

In this thesis, we first define and discuss the properties of bispanning graphs in depth. Intuitively, these are locally dense enough to allow the two disjoint spanning trees to reach all vertices, but sparse enough such that disjoint edge sets do not contain cycles. The whole class of bispanning graphs can be inductively constructed using only two operations, which makes the class tractable for inductive proofs.

We then describe in detail directed, undirected, and simplified versions of edge exchange graphs, first with unrestricted edge exchanges, and then with the restriction to unique symmetric base exchanges. These exchange graphs are related to a set of conjectures put forth by White in 1980 on base exchanges in matroids, and also to conjectures on cyclic base orderings of matroids. To date, these conjectures have not been proven in full generality, despite overwhelming computational evidence.

As steps towards showing the conjecture that the graph of unique symmetric base exchanges is connected for all bispanning graphs, we prove a composition method to construct the unique exchange graph of any bispanning graph from the exchange graphs of smaller bispanning graphs. Furthermore, using a computer program developed alongside this thesis, we are able to enumerate and make statements about all small bispanning graphs and their exchanges graphs.

Our composition method classifies bispanning graphs by whether they contain a non-trivial bispanning subgraph, and by vertex and edge connectivity. For bispanning graphs containing a non-trivial bispanning subgraph, we prove that the unique exchange graph is the Cartesian graph product of two smaller exchange graphs. For 2-vertex-connected bispanning graphs, we show that the bispanning graph is the 2-clique sum of two smaller bispanning graphs, and that the unique exchange graph can be built by joining their exchange graphs and forwarding edges at the join seam. And for all remaining bispanning graphs, we prove a composition method at a vertex of degree three, wherein the unique exchange graph is constructed from the exchange graphs of three reduced bispanning graphs.

We conclude this thesis with ideas and evidence for future approaches to proving the connectivity of the unique exchange graphs and show the most difficult bispanning graphs instances.

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First slide of the talk

Presentation "Massive Suffix Array Construction with Thrill" at DFG SPP 1736 Annual Colloquium

Posted on 2015-10-01 19:40 by Timo Bingmann at Permlink with 0 Comments. Tags: c++ talk thrill

Today, we gave an overview presentation of the vision behind Project Thrill, its current state, and how it will be used to implement suffix and LCP array construction, and many other distributed algorithms: 2015-10-01 Massive Suffix Array Construction with Thrill.pdf 2015-10-01 Massive Suffix Array Construction with Thrill.pdf.

Download 2015-10-01 Massive Suffix Array Construction with Thrill.pdf

Thumbnail of a small ternary search tree used for classification, and LCP-aware tournament tree.

Publication: Engineering Parallel String Sorting in Algorithmica Journal

Posted on 2015-09-22 15:46 by Timo Bingmann at Permlink with 0 Comments. Tags: research sorting university

Our paper "Engineering Parallel String Sorting" was accepted for publication in Springer's Algorithmica Journal, and is available online at http://dx.doi.org/10.1007/s00453-015-0071-1.

Compare to our older technical report, the journal edition contains many (minor and major) corrections, additional references and better explanations.

A pre-print version is available here: Engineering-Parallel-String-Sorting.pdf Engineering-Parallel-String-Sorting.pdf.

Download Engineering-Parallel-String-Sorting.pdf

Please refer to the main parallel-string-sorting page for details and source code.

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