New York Dyalog Meetup

I am very pleased to announce the creation of the New York Dyalog APL Meetup group, details of which can be found online at The meetup has been created and is organised by Paul Mansour, who is also sponsoring the venue for the inaugural meetup, scheduled for 6-9pm on Thursday February 7th, at WeWork, 500 7th Avenue, New York. If you are interested in meeting APL users in the New York area, please join the Meetup group so that you will be notified of future events. Please sign up for events that you intend to attend so we know you are coming!

Meetup is a service used to organize online groups that host in-person events for people with similar interests, including programming languages. In addition to the New York group, there is also an APL Meetup group in Frankfurt which meets regularly,  and a APL/J/K group in Toronto, Canada. We welcome the creation of more local meetups! If you create one in your area, remember to inform us at Dyalog so that we can add a link from our event calendar, and arrange to stop by and speak when we are in your neighborhood!

The program for the meetup on February 7th is as follows:

6:00-6:30pm: Time for Networking

6:30-8:00: Morten Kromberg: New Ways of Working with APL

When you are busy solving problems, new technology can be an unwelcome distraction – but every now and again technologies appear which have the potential to make development, maintenance or distribution significantly easier. Morten will demonstrate some of the new ways of working with APL that have become available in the last few years, and also discuss likely features in the next couple of releases of Dyalog APL: 17.1 in Q2 of 2019 and 18.0 in 2020.

8:00-8:15 Short Break

8:15-9:00 Paul Mansour: Keeping it Simple – A Git Workflow for APLers.

Abstract: Git is great, but the newcomer can easily drown in a sea of commands and options. Git doesn’t tell you when or why to branch, when or why to merge or rebase, how to version your project or prepare a release. AcreFlow is a radically simplified Git workflow that answers these questions. It is implemented in Dyalog APL so you can branch, commit, and put out new versions directly from the APL session.


Dyalog ’18 Videos, Week 7

Our stated goal has been to provide variety each week, and I’m happy to say that I have not been able to find any kind of theme in this penultimate set of presentations from Dyalog’18 in Belfast. Although the three technologies presented are all very useful, that is the only thing that they seem to have in common!

FlipDB is a relational database management system that was designed to solve complex data problems from the mortgage and asset finance business, but has grown into a general-purpose toolkit for working with tables. As Paul Mansour writes on the FlipDB web page, mortgages push the limits of many systems due to the quantity of data items, variety of products, constant innovation, and a never-ending stream of file formats and standards. Answering his own question, “What is wrong with SQL?”, Paul shows how easy it is to solve a number of programming puzzles from the Alteryx Weekly Challenge web site using the combination of array and object-orientation available in FlipDB. Just think about how difficult it would have been to do the same with SQL!

Co-dfns is a PhD project at Indiana University, executed by Aaron Hsu and partly funded by Dyalog Ltd. The aim is to build a concurrent compiler for dfns. Aaron regularly presents progress reports at Dyalog user meetings. This year, his focus has shifted to wrapping up demonstrations of completeness and other reporting required to finish his thesis – this will describe his compiler, which is designed to self-host on Data Parallel hardware. Who could have thought that analysing a lexically-scoped, dynamic, language could be so interesting (at least if you want the compiled code to run fast)?

A Jupyter Notebook is a formatted document containing live code, equations, visualizations and narrative text. As Adám Brudzewsky explains in his talk, Jupyter is an open framework that supports “language kernels” for many languages, including Dyalog APL. In other words, a notebook can contain APL expressions and their results – and the expressions can be edited and re-executed by the reader on demand. The expressions can either return textual output which is incorporated into the document, or HTML including SVG graphics – for example, output from SharpPlot or any tool that can produce HTML output.

Summary of this week’s videos:

Dyalog ’18 Videos, Week 6

Happy New Year – and Welcome to the 6th week of Dyalog ’18 video releases!

If you enjoy geometry, 2019 starts with a couple of real treats; one which builds up to the use of complex numbers just before the end, and another which starts with them and moves on to Quaternions. Alternatively, if you think vectors and matrices containing imaginary numbers are a bit esoteric, what could be more “down to earth” than taking a look at various ways to efficiently extract data from Excel spreadsheets? Finally, we have a talk on a Theory of Everything, which will obviously interest everyone!

Returning to the maths: Nic Delcros asks a seemingly trivial question about the number of dimensions of a vector. As any APLer knows, a vector is a list of numbers and, therefore, has 1 dimension, but of course the numbers in a vector nearly always represent a structure of higher dimensionality. Nic takes us on an entertaining exploration of the case where the numbers represent a dynamic event, where one of the dimensions is time – punctuated with beautiful images.

Dieter Kilsch from the University of Applied Sciences (Technische Hochschule) in Bingen obviously enjoys teaching mathematics! In this talk, he actually managed to make me think that I had some insight into why the Irish mathematician William Hamilton invented the Hamiltonian number system (which is populated by Quaternions), and how it allows us to do algebra on points in a 3-dimensional space, similar to the way complex numbers work for 2 dimensions. For example, Quaternions can be used as a tool of thought and computation for image recognition!

Returning to the very real world, Richard Procter is back with an updated talk on “Excel Mining”, following on from his talk at Dyalog ’15 in Sicily. Like many of us, he frequently needs to load data which originates in Microsoft Excel into APL for processing – and sometimes write back to Excel. Richard has tried a variety of different techniques and provides a list of questions that might decide which technique to use in a given scenario (and performance measurements as well).

It should be no big surprise that John Daintree’s big TOE is not something he needs to take a shoe off to demonstrate. Rather, the Theory Of Everything is a unifying idea that might one day replace a large number of system functions, “root methods” and I-Beams which currently allow programmers to ask questions about the Universe that they are running in. The result will hopefully be a system that is more powerful, but simpler and much more self-documenting than the collection of tools that it would replace.

Summary of this week’s videos: