Showing posts from September, 2010

The Shoulders of Giants

Last week NAG held its 34th AGM and prior to the business part of the meeting we had the pleasure of hearing a lecture by Professor Nick Higham of the University of Manchester on the subject How and How Not to Compute the Exponential of a Matrix. The lecture was filmed and can be viewed here. Matrix functions are useful in a number of areas, in particular for describing the solutions of certain types of differential equations. NAG is working with Nick to include his algorithms in future marks of the Library.

One of the things I particularly enjoyed about Nick's talk was the way that he set the subject in its proper historical context, starting with the work of 19th Century mathematicians such as Sylvester and Cayley. Working at the cutting edge of computing technology its easy to forget how much of what we do depends on work that goes back hundreds of years. It wasn't always this way: Fermat, having claimed to have found a proof of what became known as his last theorem, added…

HTML5: Possible implications for technical documentation

A New Version of HTMLAs you may have heard, HTML5, a new version of HTML, the main markup language for the web is under development. This is the first version for quite some time, HTML4.01, the current version, was released in December, 1999. There was an XML version, XHTML 1.0, XHTML (Released in January 2000 and revised August 2002), but it did not contain any new features.Much of the buzz around HTML5 concentrates on new features such as video (as an alternative to using flash plugins etc) and canvas (a JavaScript API for 2 dimensional graphics), but in this article I want to look at the features that impact on the kind of technical, mathematical documents used by NAG.SVG and MathMLSVG is an XML format for describing scalar graphics, using a similar graphics model to PostScript or PDF, but using XML syntax and CSS for styling, just as for HTML. It has been around for some years, but HTML5, for the first time, specifies how it works in the context of HTML (rather than XML). In a rel…

Do you want ice with your supercomputer?

“Would you like ice with your drink?” It’s a common question of course. One that divides people – few will think “I don’t mind” – most have a firm preference one way or the other. There are people who hate ice with their drink and those who freak if there is none. National stereotypes have a role to play – in the USA the question is not always asked – it’s assumed you want ice with everything. In the UK, you often have to ask specifically to get ice.

Yet the role of ice in making our drinks chilled is misleading. I once had a discussion with a leading American member of the international HPC community about this. “No ice”, he was complaining as we headed out of a European country, “they had no ice for the drink”.

“I don’t get this obsession with ice”, I chipped in. “What?!” He looked at me as if I were mad. “Why do you like your coke warm?”

“Ah, but that’s just it”, I replied. “I hate warm drinks – I really like my coke chilled. But surely, in this modern world over a century after th…

Working on the ADVISE project

For the past three and a half years, my colleagues and I have been working on ADVISE, a TSB-funded collaborative research project which has been developing a new toolkit for visualization and analysis. Besides NAG, the partners in the project were VSNi and the University of Leeds. VSNi have expertise in statistics, as implemented in their GenStat product, while Leeds have an international reputation for their work in visualization research. As for NAG, we've had some success with IRIS Explorer, a popular visualization toolkit which allows users to construct applications by connecting modules together via a visual programming interface.Figure 1. The ADVISE pipeline builder We retained that interface in ADVISE (see Figure 1) because it has proved to be a rather intuitive way to create, modify and interact with applications. Thus, in this figure, the user selects modules from the repository on the right and connects them together in the area on the left. The widgets for controll…