RegEx with ⎕R and ]locate

John 'Jake' JacobAPLLeave a Comment

When the British APL Association met in August Dan Baronet gave us a taster for the sort of thing that could be done with RegEx in Dyalog. I have a recording I am cleaning up but in the meantime here is a taster. First create a formatting function to push a string through ⎕xml twice just to make it easier … Read More

APL Sounds Good – Part 2: Transformers

Gil AthorayaAPLLeave a Comment

One thing that I find really interesting and impressive about the APL language is the way it transforms traditional programming language into a succinct notation. Take for example the typical mean calculation. In traditional languages: and in APL: The APL form is dense, but it summarises perfectly the intention. In signal processing there’s a similar way of transforming data from … Read More

APL Sounds Good – Part 1

Gil AthorayaAPLLeave a Comment

My first hobby code project in APL was signal processing tools. It was something I had studied in university and felt like a good candidate for APL programming. When I saw a question about sound in APL in the Dyalog forum recently, it rekindled my interest and I decided to explore the domain again, 10 years later. The question posed … Read More

Sliding Down Memory Lane

James HeslipAPLLeave a Comment

I often got frustrated with puzzles as a child. Not in the sense that I couldn’t do them, but that I would never be satisfied until I could find a solution. It’s that kind of persistence which led me to propose this problem: Sliding puzzles (Read about them on Wikipedia), like the one pictured above, are something I remember from … Read More

Dyalog Announce Dyalog Version 15.0

Paul GrosvenorAPLLeave a Comment

Dyalog today announced that version 15.0 is now available on all platforms and includes performance enhancements, new system functions, improved look and feel and a new RIDE (and lots more!). NOTE: Personal/Non-Commercial use of Dyalog APL is now completely free. The non-commercial system is a fully functional 64-bit Unicode interpreter, except on the Raspberry Pi where it remains a 32-bit … Read More

Just Meshing Around

James HeslipAPLLeave a Comment

I was working on phase one of the Dyalog Problem Solving contest for students, and I came across a problem that gave me a bit of trouble: Write a dfn that takes vectors as its left and right arguments and returns them “meshed” into a single vector formed by alternately taking successive elements from each argument. The arguments do not … Read More

Needleinahaystack

John 'Jake' JacobAPLLeave a Comment

A string of text has had all of the spaces removed: This e-mail is confidential and may be privileged. If you have received it in error, please contact the sender immediately by return e-mail then delete the e-mail and do not disclose its contents to any person. Becomes Thise-mailisconfidentialandmaybeprivileged.Ifyouhavereceiveditinerror,pleasecontactthesenderimmediatelybyreturne-mailthendeletethee-mailanddonotdiscloseitscontentstoanyperson. How do we get the words back? 1. Find a set … Read More

Experiences on the Dyalog APL Training Course

James HeslipAPLLeave a Comment

Crawley to Bramley isn’t supposed to be the most complicated journey in the world, yet somehow it turned out to be for us. My mum decided that she’d take me up there to spare me the pain of public transport. With conductor strikes and England’s train system being a bit of a mess in general, I tried my hardest to … Read More

Neural Networks and APL

Callum FloumeAPLLeave a Comment

‘Neural Network’ is a term becoming very popular in the computing business at the moment. Big technology companies are sinking large sums of money into researching, building, and harnessing neural networks. But what exactly are they and what are they used for? A quick Google search will instantly tell you that neural networks not only refer to computing but also … Read More

BAA announce free one day seminar

Paul GrosvenorAPL, EventsLeave a Comment

The British APL Association is pleased to announce a free one day seminar on Friday 20th May 2016 in The Tavern Room at the RSA London. The event will include Guest Speakers, Workshops and a chance to Network. The BAA AGM will also be on the day. A light lunch and refreshments throughout are included with your registration. ALL ATTENDEES … Read More

Tricky Triangle Trivia

Callum FloumeAPLLeave a Comment

For this week’s problem we’ve sought inspiration from Project Euler. I’ve been working through the problems there and got the group involved where I’ve struggled. This particular problem is one that we’ve yet to find a satisfying solution to. So we’re looking to the APL community for help. Highly divisible triangular number 1, 3, 6, 10, 15, 21, 28, 36, … Read More

Image Filters in APL

Callum FloumeAPLLeave a Comment

Today we live in a very competitive world. Each company wants you to buy it’s product and more than likely, they have a competitor. So how do we decide which product to buy? A lot of it comes down to advertising and how the different companies market their products. Magazines, TV ads, models, these are all weapons used to conduct … Read More

Counting Cards in APL

Sam GutsellAPLLeave a Comment

When I first started APL in August 2012, I was pointed in the direction of the annual International APL Problem Solving Competition run by Dyalog. I used it as method to practice what I had learnt. While I looked at the problems I saw one based on the poker game Texas hold ’em. It revolved around calculating the value of a hand with … Read More

The Skirting Board Problem – Solved

Gil AthorayaAPLLeave a Comment

This problem looks deceptively simple at first glance, but in the science of optimisation it is actually considered a hard problem to solve as the time to calculate a solution increases exponentially with the size of the problem. Ignoring that I focused on coding an algorithm to find the solution for the given input. After some considerable thought and experimentation … Read More

Creating Logical Search Vectors

Peter MerrittAPLLeave a Comment

We are all well aware of the power of manipulating logical vectors. However, those happy-go-lucky users out there just keep pushing the boundaries (and their luck). Some time back, we were presented with a semi-formatted character vector (from several source files) containing code-delimited sets of data, something like: “…OpenCodeF$ text number number more text other ClosingCodeF$ stuff stuff number OpenCodeB$ … Read More