ICSE proper finished on Friday, but a few brave souls stayed around for more workshops on Saturday. There were two workshops in adjacent rooms that had a big topic overlap: SE Foundations for End-user programming (SEE-UP) and Software Engineering for Computational Science and Engineering (SECSE, pronounced “sexy”). I attended the latter, but chatted to some people attending the former during the breaks – seems we could have merged the two workshops for interesting effect. At SECSE, the first talk was by Greg Wilson, talking about the results of his survey of computational scientists. Some interesting comments about the qualitative data he showed, including the strong confidence exhibited in most of the responses (people who believe they are more effective at using computers than their colleagues). This probably indicates a self-selection bias, but it would be interesting to probe the extent of this. Also, many of them take a “toolbox” perspective – they treat the computer as a set of tools, and associate effectiveness with how well people understand the different tools, and how much they take the time to understand them. Oh and many of them mention that using a Mac makes them more effective. Tee Hee.

Next up: Judith Segal, talking about organisational and process issues – particularly the iterative, incremental approach they take to building software. Only cursory requirements analysis and only cursory testing. The model works because the programmers are the users – they build software for themselves, and because the software is developed (initially) only to solve a specific problem, so they can ignore maintainability and usability. Of course, the software often does escape from the lab, and get used by others, which leads to a large risk of using incorrect, poorly designed software leading to incorrect results. For the scientific communities Judith has been working with, there’s a cultural issue too – the scientists don’t value software skills, because they’re focussed on scientific skills and understanding. Also, openness is a problem because they are busy competing for publications and funding. But this is clearly not true of all scientific disciplines, as the climate scientists I’m familiar with are very different: for them computational skills are right at the core of their discipline, and they are much more collaborative than competitive.

Roscoe Bartlett, from Sandia Labs, presenting “Barely Sufficient Software Engineering: 10 Practices to Improve Your CSE Software”. It’s a good list: Agile (incremental) development, Code management, mail lists, checklists, make the source code the primary source of documentation. Most important was the idea of “barely sufficient”. Mindless application of formal software engineering processes to computational science doesn’t make any sense.

Carlton Crabtree described a study design to investigate the role of agile and plan-driven development processes among scientific software development projects. They are particularly interested in exploring the applicability of the Boehm and Turner model as an analytical tool. They’re also planning to use grounded theory to explore the scientists own perspectives, although I don’t quite get how they will reconcile the contructivist stance of grounded theory (it’s intended as a way of exploring the participants’ own perspectives), with the use of a pre-existing theoretical framework, such as the Boehm and Turner model.

Jeff Overbey, on refactoring Fortran. First, he started with a few thoughts on the history of Fortran (the language that everyone keeps thinking will die out, but never does. Some reference to zombies in here…). Jeff pointed out that languages only ever accumulate features (because removing features breaks backwards compatibility), so they just get more complex and harder to use with each update to the language standard. So, he’s looking at whether you can remove old language features using refactoring tools. This is especially useful for the older language features that encourage bad software engineering practices. Jeff then demo’d his tool. It’s neat, but is currently only available as an Eclipse plugin. If there was an emacs version, I could get lots of climate scientists to use this. [note: In the discussion, Greg recommended the book Working effectively with legacy code].

Next up: Roscoe again, this time on integration strategies. The software integration issues he describes are very familiar to me. and he outlined an “almost” continuous integration process, which makes a lot of sense. However, some of the things he describes a challenges don’t seem to be problems in the environment I’m familiar with (the climate scientists at the Hadley Centre). I need to follow up on this.

Last talk before the break: Wen Yu, talking about the use of program families for scientific computation, including a specific application for finite element method computations.

After an infusion of coffee, Ritu Arora, talking about the application of generative programming for scientific applications. She used a checkpointing example as a proof-of-concept, and created a domain specific language for describing checkpointing needs. Checkpointing is interesting, because it tends to be a cross cutting concern; generating code for this and automatically weaving it into the code is likely to be a significant benefit. Initial results are good: the automatically generated code had similar performance profiles to hand generated checkpointing code.

Next: Daniel Hook on testing for code trustworthiness. He started with some nice definitions and diagrams that distinguish some of the key terminology e.g. faults (mistakes in the code) versus errors (outcomes that affect the results). Here’s a great story: he walked into a glass storefront window the other day, thinking it was a door. The fault was mistaking a window for a door, and the error was about three feet. Two key problems: the oracle problem (we often have only approximate or limited oracles for what answers we should get) and the tolerance problem (there’s no objective way to say that the results are close enough to the expected results so that we can say they are correct). Standard SE techniques often don’t apply. For example, the use of mutation testing to check the quality of a test set doesn’t work on scientific code because of the tolerance problem – the mutant might be closer to the expected result than the unmutated code. So, he’s exploring a variant and it’s looking promising. The project is called matmute.

David Woollard, from JPL, talking about inserting architectural constraints into legacy (scientific) code. David has been doing some interesting work with assessing the applicability of workflow tools to computational science.

Parmit Chilana from U Washington. She’s working mainly with bioinformatics researchers, comparing the work practices of practitioners with researchers. The biologists understand the scientific relevance , but not the technical implementation; the computer scientists understand the tools and algorithms, but not the biological relevance. She’s clearly demonstrated the need for domain expertise during the design process, and explored several different ways to bring both domain expertise and usability expertise together (especially when the two types of expert are hard to get because they are in great demand).

After lunch, the last talk before we break out for discussion. Val Maxville, preparing scientists for scaleable software development. Val gave a great overview of the challenges for software development at iVEC. AuScope looks interesting – an integration of geosciences data across Australia. For each of the different projects. Val assessed how much they have taken practices from the SWEBOK – how much have they applied them, and how much do they value them. And she finished with some thoughts on the challenges for software engineering education for this community, including balancing between generic and niche content, and balance between ‘on demand’ versus a more planned skills development process.

And because this is a real workshop, we spent the rest of the afternoon in breakout groups having fascinating discussions. This was the best part of the workshop, but of course required me to put away the blogging tools and get involved (so I don’t have any notes…!). I’ll have to keep everyone in suspense.

Reflections on SE for the Planet at ICSE
Blogging from ICSE - Friday

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