This is the last day of Dyalog ’14 so this is the last of six daily postcards from Eastbourne – we hope you have enjoyed getting a flavour of things as they happened. We expect there will be more discussion to come once we’re back and rested!

Last Night’s Banquet

Yesterday culminated in the traditional banquet dinner – the highlight of the social element of the user meeting. This year it was held at The Grand Hotel Eastbourne and consisted of a Champagne reception and formal three course dinner with live music from a string trio.

During the banquet the winners of the scavenger hunt were presented with their prizes – the ducks and other “British” items we saw on Sunday’s postcard! There was also a quiz to identify Dyalog employees from a list of clues. Exquisite food and wonderful company meant an exceptionally late night (early morning!) …

Discussion Point: Read-only Component Files

In his presentation today on component files and the Dyalog File Server (DFS), Richard mentioned a perhaps little-known problem with restricting access permissions on component files for users that nominally only ever read them. Setting read-only permission at the file level – that is, imposed by the operating system – could add a level of security to the file but it is in fact the case that component file reads can occasionally require write access to the file.

For example, suppose User A is reading and writing to a journaled component file and User B is simply ⎕FREADing it. If User A is interrupted whilst updating the file (perhaps the APL session is killed or a network connection is lost) and User B is the next to read it then as part of that read the interpreter will detect the journal and complete the unfinished update – a process which requires write access. If the systems administrator who set up the file permissions for User B had only granted read-only file permission to the file then the ⎕FREAD would fail.

Richard explained that this restriction might be lifted in future and that read operations would be truly read only – even with a journal present – but there is another issue to be aware of too. Access to component files is controlled using file locks. As might be expected, exclusive access is obtained on an exclusive tie and shared access is obtained on a share tie. In addition, writes to a share tied file require exclusive access for the duration of the write so that no other client is able to read it while it is being updated. Exclusive locks are write locks and thus require write permission. Therefore, if there is no write access to the file the interpreter cannot exclusively tie it – it can only share tie it.

Where file access has to be locked down as securely as possible, the DFS is able to resolve the above issues and more besides – client access to all component files is only possible via APL, users are fully authenticated and individual rights are controlled by the access matrix.

And Also …

Some of the other things we saw and heard today:

• Andy showed us how to close trace windows without cutting back the stack
• Ziggi pointed out that a loss rate of one in 700 is acceptable when delivering wine but not when delivering children
• We would like your suggestions and comments about the user meeting programme and structure, and preferred location for next year – please email us at conference@dyalog.com

Eastbourne

Eastbourne has not let us down and even the British weather (which is always unpredictable) defied the odds and rendered the ponchos and umbrellas unnecessary. The View Hotel started life as a conference centre and was purpose built for holding meetings such as ours. We have certainly found it to be an ideal venue and feedback from delegates has been overwhelmingly positive.

The picture of the pier below was carefully framed not to show the fire damaged part! The fire that destroyed part of it back in July was headline news; the pier is closed as a result but should partially reopen next week. Perhaps we will have to return when it is fully restored!

Signing Off

And so Dyalog ’14 has come to an end. It has been the best-attended Dyalog conference anyone can remember and reflects the growing success of Dyalog and its users. Here begins the countdown to Dyalog ’15!

It’s been another busy day at Dyalog ’14; there’s lots to write about and little time to do it!

Winners of the International APL Programming Contest 2014

This year, 710 registrations were received for the annual APL Programming Contest and the two main winners – Emil Bremer Orloff, student entrant from Aarhus Universitet, and Iryna Pashenkovska, professional entrant from SimCorp and a recent Engineering Mathematics graduate of National Taras Shevchenko University of Kyiv – won invitations to Dyalog ’14 as part of their prizes where they each made presentations about their contest submissions. Look forward to the videos of their presentations which will be available shortly!

Discussion Point: Data Binding – Reloaded

John Daintree showed more aspects of Dyalog’s data binding. Did you know that you can bind to XML stored in files? Did you know that you can create DataTables to bind to an APL matrix? The cddb database sample was re-worked to allow the GUI to bind to the data in a matrix as an alternative to vectors of namespace. Syncfusion controls were used to visually explore the cddb data.

John discussed changes that might come in 14.1, including better support for bound matrices.

Discussion Point: Syncfusion Controls

Late yesterday, Brian Becker showed how to take advantage of the Syncfusion Javascript controls that are bundled with Dyalog v14.0 on all platforms. This morning, Morten Kromberg and Michael Hughes followed up with demonstrations of how easy it is to enhance applications with Syncfusion controls for Windows Presentation Foundation, which are included with the Windows editions of version 14.0.

With Dyalog (as in any Microsoft.NET language), you have the choice of instantiating and manipulating WPF objects with APL language statements, or using declarative eXtensible Application Markup language, which can either be edited by UI design experts using WYSIWYG tools, or (of course) generated from APL.

Code sample for the RangeSlider:

     ∇ window←RangeSliderControl values;⎕USING;r;t
[1]   ⍝ Simple Sparkline example - inspired by Dick Bowman
[2]   ⍝ More at http://www.apldapldoo.info/apl/APL/Tutorials/WPF/SyncFusion/overview.html
[3]   ⍝ values: Numeric vector of values
[4]
[5]    :Section xaml
[6]        xaml←ScriptFollows ⍝ Picks up following comments as data
[7]    ⍝<Window
[8]    ⍝  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
[9]    ⍝  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
[10]   ⍝  xmlns:sftools="clr-namespace:Syncfusion.Windows.Tools.Controls;assembly=SyncFusion.Tools.WPF"
[11]   ⍝  Title="Syncfusion Range Slider" SizeToContent="Height" Width="400">
[12]   ⍝  <StackPanel>
[13]   ⍝    <sftools:RangeSliderControl Name="rangeslider" />
[14]   ⍝    <TextBox Name="textbox" MinHeight="25" MinWidth="100"
[15]   ⍝             HorizontalContentAlignment="Right"
[16]   ⍝             VerticalContentAlignment="Bottom"
[17]   ⍝             Background="Turquoise"/>
[18]   ⍝  </StackPanel>
[19]   ⍝</Window>
[20]   :EndSection
[21]
[22]   window←LoadXAML xaml
[23]   (r t)←window.FindName∘⊂¨'rangeslider' 'textbox'
[24]   ⎕USING←,⊂'Syncfusion.Windows.Tools.Controls,Syncfusion/4.5/Syncfusion.tools.WPF.dll'
[25]   r.onRangeChanged←'RangeChanged'
[26]   r.Range←⎕NEW DoubleRange values
[27]   window.Show
[28]
[29]   window.(slider textbox range)←r t r.Range ⍝ expose extra "properties"
     ∇

James Bond or Johnny English?

This year we enrolled our delegates in ‘Spy School’ and gave them the chance to be a spy for a few hours. In an interactive mission that included GPS tracking, teams were given a tablet preloaded with a series of spy related challenges that took place around the local area. The challenges were only activated when the GPS verified the team was in exactly the right location and points were awarded for completing each challenge successfully – the team with most points was the winner. To pile on the pressure, each team had an interactive map showing not only their location but also that of the other teams along with a live scoreboard.

The challenge certainly brought out the competitive side of the delegates and Eastbourne is probably still recovering from the shock of ten teams of APLers carrying out their covert missions around the town centre and promenade. When the final scores were in, it was a very closely run thing with Team Sprat in second place and Team Dover Sole, headed up by a super competitive John Daintree, as the eventual winners. At the final de-briefing we got to see the videos and photos submitted by each team which showed great creativity along with some very over active imaginations! Everyone had a fantastic afternoon with plenty of laughter and not too many injuries (although I am led to believe there may be a broken fingernail or two) and a big thank you to Pretty Clever Events for running the show.

Coming up…

Today is due to end with the banquet dinner in the Grand Hotel which we’ll try to include in tomorrow’s postcard.

We conclude events tomorrow with two Dyalog and two user presentations in the morning followed by the closing session at which all of Team Dyalog will be present and open to questions. In the afternoon are the remaining Technical Workshops.

The weather predictions have been spot on so far; it’s been another lovely sunny day at Eastbourne – here was the scene this morning at sunrise:

It was another busy day of presentations – read on for some highlights! After dinner tonight the evening will be rounded off with Morten and his Dancing ‘Bots – controlling two robots in parallel.

Discussion Point: Chart Design

As he demonstrated Chart Wizard – a front-end to help building SharpPlot charts – Nic pointed out a few useful tips about chart design:

• Transparency is your best friend
  SharpPlot supports transparency, which not only allows multiple layers of drawings to be readable, but also lightens the global visual impression, making charts more 21st-century
• 3D is not as cool as it looks
  The 2D alternatives (Bubble chart, Contour plot) are generally more readable, because perspective can hide data in automated 3D charts.
• Logarithmic scales are too often neglected
  They can improve readability in many cases, for example stock value, performance comparisons, or wealth repartition
• Box & Whiskers for categorised data exploration
  A very effective tool to explore the repartition of values amongst a un-modelled, yet categorised, numerical dataset.

Paul’s Poncho

The registration packs that delegates received included a stick of rock and a rain poncho generously donated by Optima Systems. As these items were unfamiliar to many from overseas, Paul Grosvenor – Optima Systems’ Managing Director – modelled them for us.

Behind The Scenes

Behind each presentation at Dyalog ’14 is a team of people taking care – hopefully mostly unnoticed – of all the AV requirements. Jason and Jonathan are working full-time in the AV suite and they are being assisted by a rota of Dyalog staff and Liam Flanagan, who has temporarily returned to us for the event, as microphone runners and camera operators. In total there are ten audio feeds and three video feeds, and every presentation is being recorded.

Generally, each presenter has different software and hardware needs and we allow everyone to use their own kit. In past years this has meant that changeovers have sometimes been less than seamless so this time we are experimenting with a system that allows one presenter’s equipment to be set up while the previous session is still taking place – this is giving a really noticeable speed-up in the changeover times.

Over the coming weeks the recordings will be edited and released online. The presentations will be released at the rate of approximately two per week as each generally takes around six to eight hours to edit and needs to be reviewed and approved by the presenter.

And Also …

Some of the many other things we saw and heard today:

• Kai Jaeger told us that software support such as Acre is essential to prevent chaos when there are multiple programmers working on the same project
• Gianfranco Alongi observed that maintenance is not cool, but said that if your product is not being maintained then the chances are it is already dead
• SimCorp maintains 1.7 million lines of APL code
• Stephen Mansour said that the biggest difference between Dyalog and other stats tools such as R is the existence of defined operators
• Nick did not use Powerpoint in his presentation but instead had a text-only equivalent that he wrote himself in coffeescript
• Aaron Hsu announced that his Co-dfns compiler would soon be available on GitHub for download
• Brian demonstrated MiServer 3’s ability to display CIA data
• Bjørn introduced the Dyalog Cryptographic Library which is now available for use

Did You Know?

John Scholes and Geoff Streeter started writing the Dyalog APL interpreter this day in 1981?

Tomorrow…

Tomorrow morning’s schedule includes two Dyalog and two user presentations. The afternoon will be dominated by the Viking Challenge (don’t forget to wear outdoor clothes and shoes that are suitable for walking!) followed by the prize ceremony for the International APL Programming Contest 2014. The two winners (one student and, for the first time, one non-student) will talk about how they achieved their victory. Everyone is encouraged to give this next generation of APLers their full support. The banquet will round off the day.

Monday opened with registration for what is the biggest Dyalog user meeting on record – it could have been even bigger but we had to turn some people away because there was no more room available. In total there are 126 attendees (even more that when we went to print with the programme!) made up from 95 delegates, 12 spouses and partners, and 19 Dyalog employees from around the world as shown.

Discussion Point: DNA Analysis

Charles Brenner performs forensic analysis of DNA and DNA mixtures – an intensive mathematical process. Others use complicated statistical and Monte Carlo methods but by using APL as his tool of thought, Charles has devised techniques which are more accurate and many times faster than competing applications supported by multi-million dollar funding.

Discussion Point: A Different Kind of Selfie

In today’s session “The Tuning Pipeline”, Roger Hui noted that for the index-of family of functions, a faster algorithm is often possible if the left and right arguments are “the same”, up to a factor of two. “The same” means the that the values have identical references so that they can be compared with a simple and quick check. For example, x⍳x is a selfie but x⍳0+x or x⍳(⍴x)⍴x are not.

For example, for the inverted-table index-of 8⌶,

      u←(' ',⎕a,⎕d)[?8e4 30⍴37]
      x←u[?1e5⍴≢u;]
      p←,⊂x
      q←,⊂x
      cmpx 'p(8⌶)p' 'p(8⌶)q'
  p(8⌶)p → 3.98E¯3 |    0% ⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕                      
  p(8⌶)q → 8.72E¯3 | +118% ⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕

Selfies occur in less obvious places – when finding uniques (∪x), in the key operator, and in x∧.=⍉y as well as in x⍳x and ⍳⍨x. You can try this yourself for various datatypes. A selfie which is not faster is an opportunity for a performance improvement.

Discussion Point: Sorting is Faster Than Grading

Also in “The Tuning Pipeline” session, Roger Hui and Kimmo Kekäläinen looked at some of the recent performance improvements in Dyalog. It has long had idioms for sorting ({⍵[⍋⍵]}, {⍵[⍋⍵;]}, etc.) Interestingly, for some common datatypes, sorting is faster than grading. You can try this yourself for various datatypes:

      cmpx '{⍵[⍋⍵]}x' '⍋x' ⊣ x←?1e6⍴2e9
  {⍵[⍋⍵]}x → 3.23E¯2 |    0% ⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕                         
* ⍋x       → 8.34E¯2 | +158% ⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕

The point is written up in this essay on the J website. The webpage uses J but the explanation applies to APL (or any other language). Quoting from the webpage: “Grade needs to keep track of the argument array and the list of indices. Sort just needs to keep track of the first. … When the argument items can be manipulated efficiently, as would be the case when the items are machine units (1, 2, 4, or 8 bytes), then sort can eschew a separate index array.”

John Scholes’ “Distractions” – An Objective Review

An awed silence gripped the room as John unveiled ground-breaking techniques for minimising life’s distractions and maximising programming productivity. It is too early to say how far-reaching this approach will turn out be in real life situations and whether it will affect The Global Economy as a whole. John appeared to have all categories of distraction covered. Let’s see. Like Woodstock ’69 and The Isle of Wight ’70, in years to come you may be able to say “I was there”.

And Also …

Some of the many other things we saw and heard today:

• Dyalog has taken on two new employees since Dyalog ’13
• John Daintree can’t take selfies but embraces high resolution touch devices
• Data files used in Finnish pension microsimulations reduced to one sixth of their size when component file compression was enabled
• MyDyalog launched live at the user meeting
• Fiona wants to promote your APL application in a banner on the Dyalog homepage
• Morten computed Mandlebrot set images, performing the calculation in parallel with isolates running on servers in Holland and Hong Kong

Tomorrow…

Tomorrow’s schedule features five user presentations and four Dyalog presentations covering the themes of code management and reuse, performance, presentation tools and cryptography. In the evening Morten will demonstrate the progress he has made with the ‘bots (something that should be very familiar to regular readers of the Dyalog blog!).

Today at Dyalog ’14 was a day of Technical Workshops: six half-day sessions and one all-day session were held, and there will be more at the end of the user meeting on Thursday.

This evening Gitte will informally welcome the attendees before Vibeke introduces the scavenger hunt and Karen and Jason run a traditional English pub quiz so that delegates can get to know each other and the host country a bit more.

Getting Involved

This year we plan to keep you more up to date than ever before with what is happening at the user meeting. Programme updates and supporting materials will be made available on our website. There will be blog posts each day and we are using the Twitter hashtag #dyalog14 on our tweets – we encourage everyone to join in with us whether in Eastbourne or not.

Preparations

For Team Dyalog, the start of the user meeting is the culmination of preparations spanning weeks or even months. There have been some obstacles along the way – not least the fire on the pier, which meant a replacement banquet dinner venue had to be hastily found – but the presentations are ready and everything kicks off in the morning. We are looking forward to a busy but enjoyable week!

* See this blog post

Tomorrow…

Dyalog ’14 formally begins tomorrow. We expect a busy day commencing with registration and followed by ten presentations in total, starting with a formal welcome from Gitte. As has become the custom, there will be a mixture of presentations from Dyalog Ltd, guests and invited speakers throughout the week. Monday traditionally features Dyalog presentations and this year is no exception – but we will also have Charles Bremner and Heikki Tikanmäki talking about forensic DNA analysis and pension modelling respectively. Two years ago, by popular request, we abandoned the practice of running presentations in parallel (extending the programme by a day to allow this) and all of the presentations will run sequentially again this year.

There are planned evening activities for each of the conference nights. After dinner tomorrow, John Scholes will present his observations on the subject of “distractions” – those who have attended his evening presentations before will know they can be highly entertaining!

Welcome to the first of several postcards from Dyalog ’14 in Eastbourne. The last Dyalog conference/user meeting held in the United Kingdom was at Horsley near Guildford back in 2003 and we’re looking forward to holding it on what is, for a lot of us, home ground. Eastbourne is a resort on England’s south coast known for its promenade and pier (of which more later!), its hotels, guest houses and, by no means least, its conference centres. As a bonus, we should see some decent seaside weather – we can’t promise the Florida sunshine of Dyalog ’13 but the UK is currently having a much better than average late summer; the weather forecasters say it should continue and that we’re heading for one of the driest Septembers on record so let’s hope they’ve got it right!

All but four Dyalog staff have come to Eastbourne. We’re looking forward to sharing what we’ve been working on, listening to our users’ presentations and meeting attendees old and new – this is set to be the biggest conference we have ever held with 126 registrations in total (two more than it says in the programme due to two last-minute registrations after we went to press!).

Coming Up…

The programme kicks off tomorrow with Technical Workshops all day followed by three and a half days of presentations by Dyalog staff, users and invited guests, finishing on Thursday afternoon with the remaining Technical Workshops. We’ll report on some of the highlights of these presentations over the coming week. We’re making recordings of all the presentations and some of the workshops, and will be putting them all up on the Dyalog website over the coming weeks.

We do, of course, also have our “Viking Challenge” on Wednesday as well as daily evening entertainment, culminating in the banquet on Wednesday night. Originally we had the dining suite at the end of Eastbourne Pier booked for the banquet, but, as you may have seen, Eastbourne Pier suffered a major fire at the end of July and is now closed for rebuilding. Fortunately we have been able to secure The Grand Hotel as an alternate venue, and all is back on track.

All in all we anticipate a very busy – but enjoyable and productive – week and hope to summarise the essence of it here; check back daily for reports of events!