I am always thrilled to hear from people who have been able to use APL to gain insight into difficult subjects, or use APL to pass knowledge on to others. A truly fascinating and surprising example of this at Dyalog ’23 was the talk titled “quAPL – A Quantum Computing Library in APL”, in which Marcos Frenkel presented work that he has done together with Santiago Núñez-Corrales and Bruno Abreu at the National Center for SuperComputing Applications, University of Illinois at Urbana-Champaign in the USA.

I say “surprising” because I had imagined that quantum computers were a bit like the analog computers of old, where you would initialise some “circuits” and then let the thing settle into some kind of minimal energy state – and, therefore, about as far from APL as you could get. However, when you take a closer look at quantum computing, qubit states are “matrix multiplications all the way down”. To quote Marcos: APL naturally expresses quantum concepts, leading to higher level programming constructs.

Jesús Galán López is a metallurgist at Ghent University in Belgium. In two presentations at Dyalog ’23, he explains how he has been exploring the use of APL for scientific and engineering work. He takes us on a deep dive into the use of APL to help students write better models of processes like grain growth in metals than they would be able to using traditional programming languages.

Dyalog had two interns this summer: last week’s video collection featured work done on an Array Notation implementation by Kamila Szewczyk from Saarland University. This week, Asher Harvey-Smith talks about his experience as an intern, some of the teaching materials that he worked on over the summer, and his adventures teaching algebra to his mates using APL after he returned to the University of Warwick.

Not all education happens at an institution: sometimes you have to learn APL on your own, with the help of online friends. If you are really keen, you can attend conferences and hunt down Aaron Hsu. The final talk this week is by Brandon Wilson. In a talk titled “Introspections of an Intermediate APLer – The Good, Bad, and Ugly of Learning APL“, he (in his own words) offers the perspective of a firmly middle-intermediate APLer trying to make the most of the glittering promises of “APL as a tool of thought” while the pains and joys are salient.

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This week’s videos:

• U08: quAPL – A Quantum Computing Library in APL (Marcos Frenkel)
• U09: APL and Metallurgy (Jesús Galán López)
• U10: Teaching Linear Algebra with APL (Asher Harvey-Smith)
• U15: Introspections of an Intermediate APLer – The Good, Bad, and Ugly of Learning APL (Brandon Wilson)
• U12: Grain Growth and Array Programming (Jesús Galán López)

Materials for all presentations can be downloaded from the Dyalog ’23 webpage.

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This week’s collection consists of presentations by members of the development team, and concentrates on language features and development tools that the developers are currently designing or already implementing. Many of these features are likely to be in version 20.0 of Dyalog, which we plan to release in early 2025, about a year after version 19.0 becomes available. In other words, there is still time to comment on these ideas and propose changes or additions…please take a look and let us know your thoughts!

John Daintree presents an update to the design (and prototype implementation) of so-called Token-by-Token (TBT) debugging, which will make it possible to step through code one primitive at a time rather than one line at a time. This promises to be a wonderful teaching tool, and will also help experienced users debug complex expressions – especially trains and other tacit constructs.

In the presentation on “Setting and Getting Variable Values”, Adám Brudzewsky proposes extensions that will simplify (and speed up) a number of frequently-occurring patterns, where application code needs to reference or update variables based on arrays containing variable names. At the moment, most solutions require complicated, inefficient, and uncomfortable uses of the execute primitive (which some code scanners might identify as potentially unsafe).

Adám’s second presentation also proposes ways to simplify frequently-occurring use cases, this time related to a relatively recent addition to the Dyalog language, the key operator (⌸). Similar to an SQL “group by” clause, key performs operations on groups of data that are partitioned using key values – and it suffers from similar issues if you want the results to be in a particular order, or include entries for key values that do not occur in the data which is at hand.

Peter Mikkelsen proposes a new mechanism for making shell commands from Dyalog. Rather than extending the existing mechanism (⎕SH and its synonym ⎕CMD), which is widely used by existing code bases, Peter proposes a new system function that will manage both binary and encoded input and output, and include features such as whether to error on a non-zero exit code and ways to redirect input and output

The final talk in this block is by Kamila Szewczyk, a student from Saarland University, who was an intern at Dyalog Ltd this summer. In this whirlwind talk, she covers her implementation of a prototype of an APL Array Notation deserialiser, which will be available as an I-Beam in version 19.0, and probably used by Link 4.0. When she needed a break from that project, she created internal experimental builds of the interpreter to try out a large number of interesting ideas that are present in other array language implementations, such as automatic numerical differentiation, the obverse operator, and a monadic inner product where, for example, -.× computes the determinant.

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This week’s videos:

• D03: Dyalog Version 20.0 – Part 1 (John Daintree)
• D04: Setting and Getting Variable Values (Adám Brudzewsky)
• D05: Revisiting ⎕SH and ⎕CMD (Peter Mikkelsen)
• D13: Giving Key a Vocabulary (Adám Brudzewsky)
• U16: An Implementation of APL Array Notation (Kamila Szewczyk)

Materials for all presentations can be downloaded from the Dyalog ’23 webpage.

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Welcome to the 2023 edition of the Dyalog user meeting presentation recordings. This year, we plan to release a few talks each week until the Winter Solstice – and I will be doing my best to introduce each block of related talks.

Week 1 – A New CEO!

For the 19th year running, the annual Dyalog user meeting started with CEO Gitte Christensen’s Welcome, followed by my own Technical Road Map presentation. However, all is not as it has been: this year, Gitte opened the user meeting with the announcement that she intends to retire from her role as CEO when she turns 70 at the end of this year. The final presentation in this first block is by our incoming CEO, Kirstine Kromberg, and our new Administration Assistant, Jada Andrade, who closed Dyalog ‘23 with a presentation of the vision for the future of Dyalog Ltd.

The similarity between my name and that of the new CEO is not a co-incidence – she is the daughter of the current CEO and CTO. Kirstine (Stine for short) has an MBA in Business Administration and Information Technology from Copenhagen Business School, and everyone believed she was destined to become a manager at one of the large Danish shipping or pharma companies. However, after Stine’s second maternity leave, she discovered that returning to her job as a business consultant would mean twiddling her thumbs until the consulting market picked up again after the Covid pandemic. At the same time, the search for a new CEO for Dyalog Ltd had started.

Stine has been working for Dyalog Ltd for almost four years now, learning how everything works as an accountant and CFO and running several internal projects both on the administrative and technical side of the business. This experience confirmed to us – and to the board, where half of the directors represent our largest clients – that she could strike the right balance between preserving continuity and having the “change management” skills that are required as we grow beyond 25 full-time employees.

As you will see if you watch my presentation, I have a long list of features that I want to see in Dyalog before I retire – and since everything takes longer than I think, I expect to be around for quite some time! Uncharacteristically, both the first and the last talk mention money: Gitte introduces “The APL Fund”, which will allow successful APLers to contribute to the future growth of APL, and Jada speaks about the new prices for Dyalog licences (effective from 01 January 2024). Except for an initial adjustment when Gitte and I joined Dyalog Ltd, the price of a licence has not changed in the 19 years that Gitte and I have been with the company (don’t worry, they are not changing significantly now unless you are still running a 32-bit version!).

I hope you enjoy watching the first set of recordings from Dyalog ’23!

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This week’s videos:

• D01: Welcome to Dyalog ’23 (Gitte Christensen)
• D02: The Road Ahead (Morten Kromberg)
• D19: Behind The Scenes (Stine Kromberg and Jada Andrade)

Materials for all presentations can be downloaded from the Dyalog ’23 webpage.

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