February 8th, 2016 | Categories: programming, python, R, walking randomly | Tags:

While waiting for the rain to stop before heading home, I started messing around with the heart equation described in an old WalkingRandomly post. Playing code golf with myself, I worked to get the code tweetable. In Python:

In R:

I liked the look of the default plot in R so animated it by turning 200 into a parameter that ranged from 1 to 200. The result was this animation:

The code for the above isn’t quite tweetable:

for(num in seq(1,200,1))
    filename = paste("rplot" ,sprintf("%03d", num),'.jpg',sep='')

This produces a lot of .jpg files which I turned into the animated gif with ImageMagick:

convert -delay 12 -layers OptimizeTransparency -colors 8 -loop 0 *.jpg animated.gif 
January 14th, 2016 | Categories: RSE | Tags:

Programmer writes documentation like this


User reads documentation like this

giphy (1)

January 11th, 2016 | Categories: RSE | Tags:

The Engineering and Physical Sciences Research Council (EPSRC) is the UK’s main agency for funding research in engineering and the physical sciences. In May 2015, the EPSRC made a funding call for a new type of 5-year fellowship – A Research Software Engineering Fellowship which indicated their commitment to the national Research Software Engineering movement. I am very happy to announce that I am one of the 7 successful EPSRC Research Software Engineering fellows.

The title of my fellowship project is Building Capability and Support in Research Software. The project summary is below

“Software is the most prevalent of all the instruments used in modern science” [Goble 2014]. Scientific software is not just widely used [SSI 2014] but also widely developed. Yet much of it is developed by researchers who have little understanding of even the basics of modern software development with the knock-on effects to their productivity, and the reliability, readability and reproducibility of their software [Nature Biotechnology]. Many are long-tail researchers working in small groups – even Big Science operations like the SKA are operationally undertaken by individuals collectively.

Technological development in software is more like a cliff-face than a ladder – there are many routes to the top, to a solution. Further, the cliff face is dynamic – constantly and quickly changing as new technologies emerge and decline. Determining which technologies to deploy and how best to deploy them is in itself a specialist domain, with many features of traditional research.

Researchers need empowerment and training to give them confidence with the available equipment and the challenges they face. This role, akin to that of an Alpine guide, involves support, guidance, and load carrying. When optimally performed it results in a researcher who knows what challenges they can attack alone, and where they need appropriate support. Guides can help decide whether to exploit well-trodden paths or explore new possibilities as they navigate through this dynamic environment.

These guides are highly trained, technology-centric, research-aware individuals who have a curiosity driven nature dedicated to supporting researchers by forging a research software support career. Such Research Software Engineers (RSEs) guide researchers through the technological landscape and form a human interface between scientist and computer. A well-functioning RSE group will not just add to an organisation’s effectiveness, it will have a multiplicative effect since it will make every individual researcher more effective. It has the potential to improve the quality of research done across all University departments and faculties.

My work plan provides a bottom-up approach to providing RSE services that is distinctive from yet complements the top-down approach provided by the EPRSC-funded Software Sustainability Institute.

The outcomes of this fellowship will be:

1. Local and National RSE Capability: A RSE Group at Sheffield as a credible roadmap for others pump-priming a UK national research software capability; and a national Continuing Professional Development programme for RSEs.
2. Scalable software support methods: A scalable approach based on “nudging”, to providing research software support for scientific software efficiency, sustainability and reproducibility, with quality-guidelines for research software and for researchers on how best to incorporate research software engineering support within their grant proposals.
3. HPC for long-tail researchers: ‘HPC-software ramps’ and a pathway for standardised integration of HPC resources into Desktop Applications fit for modern scientific computing; a network of HPC-centric RSEs based around shared resources; and a portfolio of new research software courses developed with partners.
4. Communication and public understanding: A communication campaign to raise the profile of research software exploiting high profile social media and online resources, establishing an informal forum for research software debate.


[Goble 2014] Goble, C. “Better Software, Better Research”. IEEE Internet Computing 18(5): 4-8 (2014)

[SSI 2014] Hettrick, S. “It’s impossible to conduct research without software, say 7 out of 10 UK researchers” http://www.software.ac.uk/blog/2014-12-04-its-impossible-conduct-research-without- software-say-7-out-10-uk-researchers (2014)

[Nature Biotechnology 2015] Editorial “Rule rewrite aims to clean up scientific software”, Nature Biotechnology 520(7547) April 2015

January 4th, 2016 | Categories: matlab | Tags:

I stumbled across a great list of resources about the R programming language recently – a list called awesome-R. The list said it was inspired by awesome-machine-learning which, in turn, was inspired by awesome-PHP. It turns out that there is a whole network of these lists.

I noticed that there wasn’t a list for MATLAB so started the awesome-MATLAB list. Pull Requests are welcome.

December 24th, 2015 | Categories: programming, RSE | Tags:

John D Cook published a great article on automation recently. He discusses the commonly-held idea that the primary reason to automate things is to save time. As anyone who’s actually gone through this process will tell you, this strategy can often backfire and John points to a comic from the ever-wonderful xkcd that illustrates this perfectly.


John suggests that another reason to automate is to save mental energy rather than time and I completely agree! This is a great reason to automate. When you are under pressure to complete a task that has to be done right first time, being able to simply push the big red button and KNOW that it will work is worth a great deal.

Automation as knowledge storage and transfer

Another use of automation is as a way to store and transfer the knowledge of how to get things done.

I work with a huge array of technologies, spending a large part of my working day poring through manuals, documentation, textbooks and google searches figuring out how to do some task, foo.  By the end of the project, I’ll be an expert at doing foo but I know that this expertise won’t last. I’ll soon be moving onto the next project, the next set of technologies and my hard-won knowledge will leak from my brain-cache as quickly as it was filled.

I often find that the fastest way to distill my knowledge of how to do something is to write a script that automates it. It’s often more concise and quicker to write than documentation and is usually useful to me and possibly others. It also serves as a great launching point for relearning the material if ever I revisit this particular set of technologies and tasks.

Automate to improve your processes

Having an automated script also allows others to easily reproduce what I have done. You want what I have? Run this thing and it’s yours. A favour from me to you!

Initially, this looks and feels like an act of pure altruism. I put in a large amount of hard work and someone else benefits. In my experience, however, payback always comes my way when those who use my work give me feedback on how to do it better.


December 23rd, 2015 | Categories: general math, just for fun, Maple, math software | Tags:

Some numbers have something to say. Take the following, rather huge number, for example:


This number wants to tell you ‘Happy Holidays’, it just needs a little code to help it out.  In Maple, this code is:

n := 18532529104068264480353131238404133659515101876112780772576330806424607039523076495646885634139967048751461005248758632306757568791464282975763655513845614593843019187655175699232981800640177552230121901623724542589154403221854439086181827152684585874764890938291566599716051702867105827305295569713835061785617174899049034655848488352249531058730460687733248824488684969031964141214711866905054239875930383262767247976845232997188307342087743859641917976242185446451606034726912968063437466250120212904972794971185874579656679344857677824:
modnew := proc (x, y) options operator, arrow; x-y*floor(x/y) end proc:
tupper := piecewise(1/2 < floor(modnew(floor((1/17)*y)*2^(-17*floor(x)-modnew(floor(y), 17)), 2)), 0, 1):
points := [seq([seq(tupper(x, y), y = n+16 .. n, -1)], x = 105 .. 0, -1)]:
plots:-listdensityplot(points, scaling = constrained, view = [0 .. 106, 0 .. 17], style = patchnogrid, size = [800, 800]);

The result is the following plot

Screen Shot 2015-12-23 at 13.03.12

Thanks to Samir for this one!

The mathematics is based on a generalisation of Tupper’s self-referential formula.

There’s more than one way to send a message with an equation, however. Here’s an image of one I discovered a few years ago — The equation that says Hi

December 13th, 2015 | Categories: general math, just for fun, math software, programming | Tags:

Way back in 2008, I wrote a few blog posts about using mathematical software to generate christmas cards:

I’ve started moving the code from these to a github repository. If you’ve never contributed to an open source project before and want some practice using git or github, feel free to write some code for a christmas message along similar lines and submit a Pull Request.

December 8th, 2015 | Categories: Open Data Science | Tags:

Back in October, I wrote about the Open Data Science events we’ve starting running at the University of Sheffield. These evening events, held at Sheffield’s The Hide are attended by researchers, students and the occasional random who have an interest in data science (collectively referred to as Data Hipsters by some).

At their core, these events are just an excuse for researchers from many disciplines to get together and explore common interests in an informal way and they’ve been a great success.

This month, we’ve gone big and not just in the ‘big data’ sense. We have two free data science events:

November 23rd, 2015 | Categories: just for fun, natural language, programming, R, The internet | Tags:

A recent trend on Facebook is to create a wordcloud of all of your posts using an external service. I chose not to use it because I tend to use Facebook for personal interactions among close friends and I didn’t want to send all of my data to another external company.

Twitter is a different matter, however! All of the data is open and it’s very easy to write a computer program to generate Twitter world clouds without the need for an external service.

I wrote a simple script in R that generates a wordcloud from the most recent 3200 tweets and outputs the top 200 words (get the code on github). The script removes many of the uninteresting words such as the, of, and that would otherwise dominate the cloud. These stopwords come from the Top100Words list of the R package qdap but I also added a few more such as ‘just’ and ‘me’ that I seem to use a lot.

This is the current wordcloud for my twitter account, walkingrandomly. Click on the image to see a bigger version. My main interests are very clear – Python programming, research software, data and anything that’s new!


Once I had seen my wordcloud, I wondered how things would look for other twitter users who I pay a lot of attention to. This is how it looks for Manchester University’s Nick Higham. Clearly he’s big on SIAM, Manchester, and Matrix Analysis!



I then looked at my manager at Sheffield University, Neil Lawrence. Neil finds data and the city of Sheffield very important and also writes about workshops, science, blog posts and machine learning a lot.



The R code that generated these wordclouds is available on github but it won’t work out of the box. You’ll need to register with twitter for app development (It’s free and fairly straightforward) and get various access keys before you can use the code.

November 19th, 2015 | Categories: Carnival of Math | Tags:

Welcome to the 128th Carnival of Mathematics, the latest in a mathematical blogging tradition that’s been ongoing for over 8 years now!

Facts about 128

It’s said that every number is interesting and 128 is no exception. 128 is the largest number which is not the sum of distinct squares whereas it is the smallest number n such that dropping the first and the last digit of n leaves its largest prime factor (thanks, Number Gossip).

Wikipedia tells us that it is divisible by the total number of its divisors, making it a refactorable number. Additionally, 128 can be expressed by a combination of its digits with mathematical operators thus 128 = 28 – 1, making it a Friedman number in base 10.

128 was also the number of kilobytes of memory available in the magnificent computer shown below.

© Bill Bertram 2006, CC-BY-2.5 — Attribution


The Princeton Companion to Applied Mathematics
I recently received a copy of the The Princeton Companion to Applied Mathematics and it’s just beautiful, definitely recommended as a christmas gift for the maths geek in your life. The companion’s editor, Nick Higham, has written a few blog posts about it – Companion authors speaking about their work, Famous Mathematicians and The Princeton Companion and How to Use The Princeton Companion to Applied Mathematics.

We have a lot of problems, and that’s a good thing
‘Diane G’ submitted this advanced knowledge problem — great practice for advanced mathematics. This blog is amazing and posts practice problems every Monday and advanced problems every Wednesday.

Linear Programming
Laura Albert McLay of Punk Rock Operations Research (great blog title!) submitted two great posts: Should a football team run or pass? A game theory and linear programming approach and dividing up a large class into discussion sections using integer programming

Francisco Yuraszeck submitted 10 Things You need to know about Simplex Method saying ‘This article is about the basics concepts of Linear Programming and Simplex Method for beginers in Operations Research.

Stuart Mumford demonstrates various ways of computing the first 10,000 numbers in the Fibonacci Sequence using Python — and some are much faster than others. Laurent Gatto followed up with a version in R.

Cleve Moler, the original developer of MATLAB, looks at three algorithms for finding a zero of a function of a real variable:

Michael Trott of Wolfram Research looks at Aspect Ratios in Art: What Is Better Than Being Golden? Being Plastic, Rooted, or Just Rational? Investigating Aspect Ratios of Old vs. Modern Paintings

Andrew Collier explores Fourier Techniques in the Julia programming language.


The Numerical Algorithm Groups’s John Muddle looks at solving The Travelling Rugby Fan Problem.

Robert Fourer gives us two articles on Quadratic Optimization Mysteries: Part 1 and Part2. These are posts concerned with computational aspects of mathematical optimization, and specifically with the unexpected behavior of large-scale optimization algorithms when presented with several related quadratic problems.

Why Was 5 x 3 = 5 + 5 + 5 Marked Wrong
This image went viral recently

It generated a LOT of discussion. Brett Berry takes a closer look in Why Was 5 x 3 = 5 + 5 + 5 Marked Wrong.


Katie Steckles submitted an article that analyses the different visual themes explored by M.C. Escher in his artwork

Shecky R writes about our curious fascination with eccentric and top-notch mathematicians in Pursuing Alexander.

Brian Hayes has been Pumping the Primes and asks “Should we be surprised that a simple arithmetic procedure–two additions, a gcd, and an equality test–can pump out an endless stream of pure primality?”

Next time

Carnival of Maths #129 will be delivered by the team at Ganit Charcha. Head over to the main carnival website for more details.