December 12th, 2016 | Categories: Open Data Science, RSE, Scientific Software | Tags:

I was in Stockholm last week to give an invited talk at the Workshop on Nordic Big Biomedical Data for Action. I was representing the Software Sustainability Institute and delivered the latest version of my talk Is Your Research Software Correct? screen-shot-2016-12-11-at-12-47-14

It was a great event which introduced me to some nice initiatives going on waaaay up north. Initiatives such as Code Refinery who’s aims align well with those of the UK’s software sustainability Institute. Code refinery was introduced by Radovan Bast — Slide deck at


Other talks included the introduction of a scalable, parallel version of BLAST, Big Data Processing for Genomics and Delivering Bioinformatics Software as Virtual Machine images. I also got chance to geek out with some High Performance Computing and Bioinformatics people over interesting Swedish food.

Slides from most of the talks are available at

October 13th, 2016 | Categories: math software, R, RSE, Scientific Software, University of Sheffield | Tags:

I was recently invited to give a talk at the Sheffield R Users Group and decided to give a brief overview of how R relates to other technologies. Subjects included Mathematica’s integration of R, Intel’s compilers, Math Kernel Library and how they can make R faster and a range of Microsoft technologies including R Tools for Visual Studio, Microsoft R Open and the MRAN for reproducibility. I also touched upon the NAG Library, Maple’s code generation for R, GPUs and Spark.

Did I miss anything? If you were to give a similar talk, what might you have included?

September 22nd, 2016 | Categories: RSE | Tags:

“It gives me great pleasure to welcome you all to the first ever Research Software Engineering conference” 

Rob Haines‘ opening line was met by thunderous applause from 202 people representing 14 different countries with a delegation that included funders, industry, academic researchers and, of course, research software engineers. The hairs on the back of my neck stood up as it dawned on me that this was a historic moment and that I was there when it happened. I wasn’t the only one


I felt like I’d come home and that these people were my tribe…and what a tribe!


Microsoft loves Linux

The conference was a mixture of talks, workshops and networking opportunities with the opening plenary given by Matthew Johnson of Microsoft Research. Microsoft was the gold sponsor for the event and the swag bag included one of these

we're not in Kansas anymore

I reflect on the fact that I’m currently using my Macbook Pro as a Windows 10 machine to access the linux subsystem — we’re not in Kansas anymore!

Microsoft is a keen supporter of the RSE movement although the job title they use is ‘Research Software Development Engineer’, a title they’ve used for several years now. An RSE (or RSDE) does much more software development than a typical researcher and more research than a typical software engineer.

The choice of job role is important since it defines how you are assessed for things such as promotion. This is an issue that some of us are working to address within academia because many RSEs are currently assessed using the same criteria as researchers.


Docker…we need more Docker

The conference included several practical workshops on all sorts of interesting topics but the most popular, by far, was the Docker workshop. It was so oversubscribed that access to the room had to be strictly controlled! Even I wasn’t allowed in and I was on the organising committee!

Fortunately, the materials are freely available on github – 


What a diff’rence a fellowship makes

I attended a discussion workshop called ‘The Role of the Research Software Engineer’ and gave a caffeine fueled lighting talk about the impact my EPSRC RSE fellowship has had within the University of Sheffield over its first six months. Slides are at but you might not get much from them since I like to talk over a set of images for things like this.

The EPSRC RSE Fellowship is the first of its kind and I believe that its had a huge impact on how the role of RSE is perceived by academic institutions. There were only 7 awards, however, so there is still so much more to be done.

Since members of the audience included representatives from various funding bodies, I wanted to help convince them that RSE fellowships are great value for money and they should consider launching their own.

Workshop materials

Here is a list of links to some of the workshop materials. If you know of one I’ve missed, please let me know.


For more information about what happened on the day see the following links

September 5th, 2016 | Categories: Open Data Science, RSE, Science, Scientific Software, tutorials, University of Sheffield | Tags:

One of the great things about being a Research Software Engineer is the diversity of work you can get involved with. I specialise in smaller interventions which means that I can be working with physicists on Monday, engineers on Tuesday, geneticists on Wednesday….you get the idea.

Last month, I got to work with some Ecologists along with Anna Krystalli. We undertook the arduous journey from Sheffield down to Exeter to deliver talks and workshops at a post-conference symposium on reproducibility in science, organised by Malika Ihle and Isabel Winney, at the International Symposium on Behavioural Ecology.

I gave my talk, Is your research software correct?, and also delivered a workshop on using projects and version control using R and RStudio in the Code Cafe style. For the full write up of the day, see the excellent blog post by Anna over at the Mozilla Science Lab blog.

Updates : More resources

August 24th, 2016 | Categories: programming, RSE | Tags:

I sometimes give a talk called Is Your Research Software correct (github repo, slide deck) where I attempt to give a (hopefully) entertaining overview of some of the basic issues in modern research software practice and what can be done to make the world a little better.

One section of this talk is a look at some case studies where software errors caused problems in research. Ideally, I try to concentrate on simple errors that led to profound scientific screw-ups. I want the audience to think ‘Damn! *I* could have made that mistake in my code‘.

Curating this talk has turned me into an interested collector of such stories. This is not an exercise in naming and shaming (after all, the odds are that its only a matter of time before I, or one of my collaborators, makes it into the list — why set myself up for a beating?). Instead, it is an exercise in observing the problems that other people have had and using them to enhance our own working practices.

Thus begins a new recurring WalkingRandomly feature.

Excel corrupts genetics data

Today’s entry comes courtesy of a recent paper by Mark Ziemann, Yotam Eren and Assam El-OstaEmail – ‘Gene name errors are widespread in the scientific literature‘ where they demonstrate that the supplementary data files for hundreds of papers in genetics have been corrupted by Microsoft Excel which has helpfully turned gene symbols into dates and floating point numbers.

The paper gives advice to reviewers on how to spot this particular error and the authors have also published the code used for the analysis. I’ve not run it myself so can only attest to its existence, not it’s accuracy.

I’ve not dealt with genetic data directly myself so ask you — what would you have used instead of Excel? (my gut tells me R or Python but I have no details to offer).

Do you have a story to contribute?

If you are interested in contributing a story where a software glitch caused problems in research, please contact me to discuss details.

Update (31st August 2016)

One of the authors of the paper, Mark Ziemann, has written a follow up of the Excel work on his blog:

August 11th, 2016 | Categories: programming, python | Tags:

This is my rant on import *. There are many like it, but this one is mine.

I tend to work with scientists so I’ll use something from mathematics as my example.  What is the result of executing the following line of Python code?

result = sqrt(-1)

Of course, you have no idea if you don’t know which module sqrt came from. Let’s look at a few possibilities. Perhaps you’ll get an exception:

In [1]: import math
In [2]: math.sqrt(-1)
ValueError Traceback (most recent call last)
in ()
----> 1 math.sqrt(-1)

ValueError: math domain error

Or maybe you’ll just get a warning and a nan

In [3]: import numpy
In [4]: numpy.sqrt(-1)
/Users/walkingrandomly/anaconda/bin/ipython:1: RuntimeWarning: invalid value encountered in sqrt
#!/bin/bash /Users/walkingrandomly/anaconda/bin/
Out[4]: nan

You might get an answer but the datatype of your answer could be all sorts of strange and wonderful stuff.

In [5]: import cmath
In [6]: cmath.sqrt(-1)
Out[6]: 1j
In [7]: type(cmath.sqrt(-1))
Out[7]: complex

In [8]: import scipy
In [9]: scipy.sqrt(-1)
Out[9]: 1j
In [10]: type(scipy.sqrt(-1))
Out[10]: numpy.complex128

In [11]: import sympy
In [12]: sympy.sqrt(-1)
Out[12]: I
In [13]: type(sympy.sqrt(-1))
Out[13]: sympy.core.numbers.ImaginaryUnit

Even the humble square root function behaves very differently when imported from different modules! There are probably other sqrt functions, with yet more behaviours that I’ve missed.

Sometimes, they seem to behave in very similar ways:-

In [16]: math.sqrt(2)
Out[16]: 1.4142135623730951

In [17]: numpy.sqrt(2)
Out[17]: 1.4142135623730951

In [18]: scipy.sqrt(2)
Out[18]: 1.4142135623730951

Let’s invent some trivial code.

from scipy import sqrt

x = float(input('enter a number\n'))
y = sqrt(x)

# important things happen after here. Complex numbers are fine!

I can input -1 just fine. Then, someone comes along and decides that they need a function from math in the ‘important bit’. They use import *

from scipy import sqrt
from math import *

x = float(input('enter a number\n'))
y = sqrt(x)

# important things happen after here. Complex numbers are fine!

They test using inputs like 2 and 4 and everything works (we don’t have automated tests — we suck!). Of course it breaks for -1 now though. This is easy to diagnose when you’ve got a few lines of code but it causes a lot of grief when there’s hundreds…or, horror of horrors, if the ‘from math import *’ was done somewhere in the middle of the source file!

I’m sometimes accused of being obsessive and maybe I’m labouring the point a little but I see this stuff, in various guises, all the time!

So, yeah, don’t use import *.

August 5th, 2016 | Categories: Linux, tutorials, Windows | Tags:

Like many people, I was excited to learn about the new Linux subsystem in Windows announced by Microsoft earlier this year (See Bash on Windows: The scripting game just changed).

Along with others, I’ve been playing with it on the Windows Insider builds but now that the Windows Anniversary Update has been released, everyone can get in on the action.

Activating the Linux Subsystem in Windows

Once you’ve updated to the Anniversary Update of Windows, here’s what you need to do.

Open settings


In settings, click on Update and Security


In Update and Security, click on For developers in the left hand pane. Then click on Developer mode.


Take note of the Use developer features warning and click Yes if you are happy. Developer mode gives you greater power, and with great power comes great responsibility.


Reboot the machine (may not be necessary here but it’s what I did).

Search for Features and click on Turn Windows features on or off


Tick Windows Subsystem for Linux (Beta) and click OK

Screen Shot 2016-08-05 at 15.30.08

When it’s finished churning, reboot the machine.

Launch cmd.exe

Screen Shot 2016-08-05 at 15.36.14

Type bash, press enter and follow the instructions

Screen Shot 2016-08-05 at 15.37.58

The linux subsystem will be downloaded from the windows store and you’ll be asked to create a Unix username and password.

Try something linux-y

The short version of what’s available is ‘Every userland tool that’s available for Ubuntu’ with the caveat that anything requiring a GUI won’t work.

This isn’t emulation, it isn’t cygwin, it’s something else entirely. It’s very cool!

The gcc compiler isn’t installed by default so let’s fix that:

sudo apt-get install gcc

Using your favourite terminal based editor (I used vi), enter the following ‘Hello World’ code in C and call it hello.c.

/* Hello World program */


int main()
    printf("Hello World from C\n");

Compile using gcc

gcc hello.c -o hello

Run the executable

Hello World from C

Now, transfer the executable to a modern Ubuntu machine (I just emailed it to myself) and run it there.

That’s right – you just wrote and compiled a C-program on a Windows machine and ran it on a Linux machine.

Now install cowsay — because you can:

sudo apt-get install cowsay
cowsay 'Hello from Windows'
< Hello from Windows >
        \   ^__^
         \  (oo)\_______
            (__)\       )\/\
                ||----w |
                ||     ||

Update 1:

I was challenged by @linuxlizard to do a follow up tutorial that showed how to install the scientific Python stack — Numpy, SciPy etc.

It’s all there :)

sudo apt-get install python-scipy

Screen Shot 2016-08-05 at 16.42.30

Update 2

TensorFlow on LinuxOnWindows is also easy:

July 27th, 2016 | Categories: RSE | Tags:

This post is also published over at the Software Sustainability Institute.

William Stein, lead developer of the computer algebra system, Sage, and its cloud-based spin-off, SageMathCloud, recently announced that he was quitting academia to go and form a company. In his talk, William says ‘I can’t figure out how to create Sage in academia. The money isn’t there. The mathematical community doesn’t care enough. The only option left is for me to build a company.’

His talk is below and slides are at


“Every great open source math library is built on the ashes of someone’s academic career.”

William’s departure is not unique. Here’s a tweet from Wes Mckinney, creator of pandas, one of the essential data science tools for Python.

Contact us

We are looking for similar stories; good research software people who felt that they had to leave academia because there wasn’t enough support, recognition or funding. Equally, we want to hear from you if you think academia is a rewarding environment for software development. Either way, please contact us at

July 12th, 2016 | Categories: HPC | Tags:

The High Performance Computing system at University of Sheffield has several different file systems available to it. We have:-

  • /fastdata – A lustre-based, shared filesystem with hundreds of terabytes of space. No backup. No quota.
  • /data – An NFS file system where each user has access to 100Gb of storage. Back-ups go back 7 days.
  • /home –  An NFS file system where each user has 10Gb. Backed up over 28 days. Mirrored.
  • /scratch – Local disk on each worker node. No back up. Uses ext4.

Lots of options with differing amounts of space, back-up policy and, as I’m about to demonstrate, performance characteristics. I suspect that many other HPC systems have a similar set up.

On our system, it’s very tempting to do everything in /fastdata. There’s lots of space, no quota, readable from all worker nodes simultaneously — good times! I try to encourage people to think about what they are doing, however. Bad things can happen if the lustre filesystem is hammered too much. Also, there can be a huge difference in performance for some operations across different filesystems.

Let’s take an example. I want to download and untar gcc 4.9.2. How long does that take on the three different filesystems?

On the scratch directory of a worker node

cd \scratch
mkdir testing123
cd testing123
time tar xfz ./gcc-4.9.2.tar.gz 

real    0m6.237s
user    0m5.302s
sys 0m3.033s

On the lustre filesystem

cd /fastdata/
mkdir testing123
cd testing123
time tar xfz ./gcc-4.9.2.tar.gz 

real    7m18.170s
user    0m6.751s
sys 0m56.802s

On the NFS filesystem

cd /data/myusername
mkdir testing123
cd testing123
time tar xfz ./gcc-4.9.2.tar.gz 

real	16m37.343s
user	0m6.052s
sys	0m23.438s

For this particular operation, there is a two orders of magnitude difference between the worst and the best option.

I’m not an expert in filesystems and I have no idea what’s causing these differences or if I’d see a similar speed difference given a different file operation. I currently have no interest in doing a robust set of benchmarks. The point I’m making is that if you are using a system that has multiple filesystems it may be worth checking if there’s an advantage to using one over the other for your particular use case.

July 6th, 2016 | Categories: RSE | Tags:

I was recently invited to a Schloss Dagstuhl Workshop on ‘Engineering Academic Software’ by organisers Carole GobleJames HowisonClaude Kirchner and Oscar M. Nierstrasz. One week of geeking-out with research software people from all over the world in lovely surroundings with as much beer and cheese as you can eat — sounds good to me!

I gave a presentation about life on the frontline of Research Software Engineering support or the RSE Accident and Emergency department as I sometimes think of it. I spent some time discussing Sheffield’s new Research Software Engineering group formed by Paul Richmond and me off the back of our EPSRC Research Software Engineering Fellowships. I also discussed a worrying trend I’ve noticed in research software — top people are leaving academia for industry, not because they want to but because of a lack of support! Slides for my talk are at


I love attending seminars like this because I get to learn about all of the wonderful things that the community is up to.  Personal highlights included:

Effective computation in physics

Meeting Katy Huff, co-author of my favourite Python book, Effective computation in physics. The only problem with this book is the word ‘physics’ in the title since it suggests that it’s only useful if you are a physicist. Totally not the case! If you are doing science in Python, get this book! Fellow blogger John D Cook, interviewed both authors of the book back in 2015 – see the write-up at

Software Heritage

Learning about the Software Heritage project that launched very recently. The project harvests and archives projects from various locations — github, Debian and the GNU Project for now. They say that ‘we preserve software, because it contains our technical and scientific knowledge.’ It’s shaping up to be a ‘Library of Alexandria of Software’. The full mission statement is over at


Software citation and credit

There was a lot of discussion about considering software as a first class scientific output and several projects were mentioned that help the situation. The force11 software citation principles address how software should be cited and is ‘an open-source webapp that tracks research software impact‘. Dan Katz’s blog post ‘How should we add citations inside software‘ is also worth a read.


What did we talk about?

Many of the participants are active on Twitter so there was a lot of live tweeting. The twitter hashtag for the workshop was #dagstuhleas. It’s been hijacked by spammers recently but there is a lot of great content there –


I’m not the only attendee to write about this workshop:

Alice Allen of the Astrophysics Source Code Library has written up a day by day account of the workshop in a way that captures what it’s like to attend a Dagstuhl seminar perfectly.


The Software Sustainability Institute was also present in force. See what they had to say over at

Slides for all presentations can be found at