Issue 38, 15 July 2004

In this issue:

For more information about any of the articles featured in this issue, please do not hesitate to contact us at

Top Story - A Momentous Meeting of Mathematical Minds

On Wednesday 16th June a very special occasion in NAG's distinguished history was held at The University of Oxford Computing Laboratory in honour of the retirement of the Director of NAG, Dr Brian Ford OBE.

To mark Brian's momentous achievements from the inception of NAG to the present day, some 30 years later, a group of mathematical minds ranging from numerical analysts to presidents of multi-national organisations gathered to reflect on the last 30 years of NAG and in particular to pay respect to Brian's contributions to the world of numerical computation.

To read more about this unique gathering please visit

NAG in the News - Getting the Picture, Visualising Financial Data Part 2

The following is an introduction to Part 2 of an article written by Jeremy Walton, Senior Visualisation Consultant at NAG that was recently published in Financial Engineering News (FEN), entitled Get the Picture: Visualising Financial Data. To read Part 1 visit

In the first article in this series, we saw how visualization can help with the understanding of financial data, and looked at some examples produced using Microsoft' Excel's charting facility. We saw that, although Excel is good for the plotting of one variable as a function of another - for example, share price vs. time - it can run into difficulties with more complex datasets which depend on more than one variable - for example option volatility. In particular, we saw that problems arise when the spacing between successive values for variables is irregular, or when there are discontinuities in the data.

To find alternative ways of plotting these more complex datasets, we must turn to other software packages, many of which have their origins elsewhere. The importance of visualization as a tool for understanding has long been recognized in many areas including science and engineering, and it is interesting to see whether packages developed for any of these fields can be used to supplement software currently being used by financial analysts.

To read the entire article please click here For information on NAG's visualisation software IRIS Explorer visit

Case Study - PowerGen optimises power plant performance using NAG algorithms

Faced with an increasingly competitive power supply market and stricter environmental targets, optimising the performance of its power plants has become a major challenge for PowerGen, a global generator, distributor and supplier of electricity.

"In view of today's commercial and environmental pressures, the criteria for optimisation in a power plant are typically based on either minimising the NOx emissions whilst limiting the amount of unburnt fuel (carbon) left in the boiler ash or minimising the amount of unburnt fuel whilst setting a limit on the NOx emissions", said Dr Ian Mayes, Senior Engineer in the Software Engineering Group at PowerGen's Power Technology Centre in Nottingham.

Optimisation of power plant performance based on these criteria represents a major challenge since it is very difficult to reduce both unburnt carbon and NOx at the same time. There was really only one effective way forward - the development of a software model of the combustion process in the boiler of the coal-fired power plant. In writing and developing the model, PowerGen turned to NAG for mathematical analysis software that could be integrated within its specialist application.

To read the entire PowerGen Case Study please click here. For more information on NAG's numerical software visit

General Information - Your NAGNews!

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Tips & Hints - Using Example Programs within the NAG Libraries

Not sure how to get started with a NAG library routine?

We've included some code to speed up the process. With each of our library products NAG provide example programs and, where relevant, data files, exercising every routine in the library. Along with NAG's detailed documentation, the example programs can be useful program templates for you to edit to help you get started.

For example: you want to use NAG's nag_opt_nlp (e04ucc), an optimisation routine for a non-linear objective function with linear and non-linear constraints contained in NAG's C Library. To access the source code of the example program relevant for your implementation and any data, simply look for these on the release media. The precise location of the information is given in the Installer's Note.

If you haven't access to the programs, perhaps because whoever installed the product chose not to install them onto your hard disk, then NAG does provide some useful generic programs on its web site. and for example

The Fortran example programs and data are stored alongside the documentation files and are accessible from via the individual chapter and routine routes. These programs are generic DOUBLE PRECISION programs, which is the most widely used version of our libraries; you should check that your library is not single precision.

The user is strongly advised not to type in the example programs from the documentation. Apart from the possible introduction of errors and the waste of effort, the question of precision for the Fortran libraries is a common pitfall. The generic 'real' being type literally as REAL when in all probability it should be DOUBLE PRECISION.

Also included is a script file (Nagex.bat for Windows versions) that will compile and run any of the example programs to allow you to verify them on your system. Similar instructions apply to the NAG Fortran Library and the NAG Fortran 90 Library (fl90). Please note that the NAG Fortran Library example programs can be used in conjunction with the NAG SMP Library.

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