Issue 42, 6 January 2005

In this issue:

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

NAG Colloquium & AGM 2004 Review – "Computational Software in the 21st Century"

The NAG 2004 Colloquium "Computational Software for the 21st Century" was held on 10 December 2004 at the Oxford University Computing Laboratory. In the afternoon Dr Alan Scowcroft presented the invited NAG AGM Lecture on "Issues in Portfolio Construction".

The colloquium opened with a talk entitled "The Good Old Bad Old Days", by Mick Pont, of NAG. The talk described the evolution and mechanics of the NAG Library Engine, from which the NAG Fortran and C Libraries are developed. The second talk was given by Mike Dewar, also of NAG, entitled "The Answer is Blowing in the Wind ...". The talk was concerned with the semantic web, access to information and resources, and future computational services via the Web, as envisaged and investigated within the recently completed EU-funded project, MONET (see:

Dr Anne Trefethen, Deputy Director of the e-Science Core Programme, followed, giving a presentation on "Computational Science: Directions and Requirements". Examples of impressive, large-scale applications of computational science drawn from the e-Science programme were shown, which require vast amounts of computation, or data, or both. She stressed the need for standards and new 'agile' algorithms, both computational and visual. Tony Kennedy, Professor of Computational Science in the School of Physics at the University of Edinburgh delivered the final talk of the colloquium entitled "Post Palaeolithic Software" which looked at the history of computational languages and software.

Dr Alan Scowcroft, Head of Global Equities Quantitative and Derivatives Research at UBS delivered this year's invited AGM lecture on "Portfolio Construction". The work of Markowitz had shown that a mix of shares could be formed so that the projected return could be maximised for a given risk. This however was theoretical. Dr Scowcroft easily demonstrated that if some estimated returns were too optimistic then the optimisation process would tend to choose these as opposed to more conservative estimates. The optimisation process tends to make the errors optimally bad!

Having discussed estimation error, he noted that if fund managers wish to track the market then they merely need to buy a basket reflecting the market. In order to outperform, extra information which they have, or believe that they have, needs to be fed into the system. Dr Scowcroft went on to discuss means of implementing market signals from different and inconsistent sources in an optimal way. He noted that mixed estimation techniques provide a suitable framework for combining multiple forecasts and that extensions of the basic approach allow for the inclusion of stock-specific forecasts.

Links to individual presentations given at the NAG Colloquium will be featured in forthcoming issues of NAGNews.

In the News – The Visualization Handbook

An article entitled NAG’s IRIS Explorer by Senior Technical Consultant at NAG, Jeremy Walton, has been published in The Visualization Handbook (C.D. Hansen and C.R. Johnson, eds.), Elsevier, 2005. The article is an authoritative introduction to all aspects of NAG’s IRIS Explorer™. A short introduction to the original article features below.

Data visualization can be defined as the gaining of insight by making a picture out of numbers, and the important role that it plays in the effective interpretation and analysis of numerical data has been recognised for a long time. The type of data to be analysed can vary from 1D time series (e.g., yearly changes in salary) to multidimensional vector-based datasets (e.g., air flow over an airplane wing). Although the simpler types of data can be effectively displayed using ubiquitous desktop applications such as Excel, more complex data require more sophisticated visualisation techniques and applications.

To read Jeremy’s original article in its entirety please visit For more information on NAG’s IRIS Explorer visit

Free Trial – NAG’s IRIS Explorer

"We selected IRIS Explorer for the accuracy and reliability of the graphical results it produces from scientific calculations." - Dr. Jamie Shiers, Co-ordinator of OO software development at CERN/IT.

For those who need a powerful and flexible 3D visualization application IRIS Explorer™ is the most advanced visual programming environment for 3-D data visualization, animation and manipulation available today. Its easy to use point-and-click interface means that users spend less time programming and developing customised visualization applications. The extensive library of 'modules' (software routines) included put a wide range of advanced visualization and analysis techniques at users' fingertips. Simply select modules from the library and connect them to interactively read and visualise data for analysis, presentation and publication.

NAG is delighted to offer the readers of NAGNews the chance to trial its visualization software IRIS Explorer. To sign up for this 30 day offer please email us at More information on IRIS Explorer can be found here.

Tips & Hints – NAG Statistical Add-Ins for Excel

The Statistical Add-Ins for Excel have proved very popular amongst the Excel community. A unique selling point is the facility to automatically update results when data changes. This is achieved by delivering computed results as an Excel array function. Some users find that the standard Microsoft mechanism for using array functions is too complicated since users have to select all the cells they want to contain the results and also users must press 'control-shift-enter' rather than just 'enter'.

The macro below may be used to simplify this procedure. Simply call the NAG function as you would with a normal scalar function. When this macro is made available by opening the workbook containing the macro, call the macro from the Tools\Macro\Macros menu. The cell selected on the worksheet should contain the result from the NAG Add-In and look like <List of n>, where n is an integer. The macro will expand this scalar result to the full array result, using just the right number of worksheet cells.

To put this macro into a workbook click on the Tools\Macro\Visual Basic menus. In the Visual Basic window click on the Insert\Module menus. Paste the macro into this module and close the Visual Basic window. Save the workbook.

If you want the macro to be available automatically whenever you use Excel then the workbook created should be called Personal.xls and should be located in the Office\Xlstart directory. This will be automatically opened whenever Excel starts. If you want to hide this workbook then it may be hidden using the Hide option in the Windows menu.

Sub Expand()

Dim s As String, t As String

Dim n As Long

  s = Selection.Cells(1).Value

  t = Selection.Cells(1).Formula

  n = Len(Trim$(s))

  s = Left$(s, n - 1)

  s = Right$(s, n - 1 - 9)

  n = Val(s)

  Range(Selection, Selection.Offset(n - 1, 0)).Select

  Selection.FormulaArray = t

End Sub

For more detailed product information on NAG’s Statistical Add-Ins for Excel and to sign up for a free trial please click here, or email us directly at

Events – DevWeek 2005, London
  • DevWeek, London
    DevWeek is the UK’s leading technical conference for software developers, and features expert speakers on a wide range of topics, including Visual Studio 2005 ('Whidbey'), SQL Server 2005 ('Yukon'), C# 2.0, ASP.NET 2.0, Windows Forms 2.0, Security, Debugging and Web Services.

    The 8th annual event takes place in London from 21 – 25 February 2005, and NAG is delighted to be exhibiting. For more information about this key event in the software development calendar visit the website at

Product News - New Implementations

NAG is committed to offering new implementations of its broad range of numerical and statistical software, compilers and tools. Since the last edition of NAGNews platform availability has increased for the NAG C and Fortran Libraries and the NAG Data Mining & Cleaning Components (DMC).

The NAG C Library, Mark 7 is now also available for the following platforms:

  • AMD-64 Linux64 using the gcc 3.3 Compiler
  • Intel-32 Linux using the Intel C++ v8.0 Compiler

The NAG Fortran Library, Mark 20 is now also available for the following platform:

  • Intel-64 Linux64 using the Intel v8.0 Compiler

The NAG DMC, Release 2.0 is now available for the following platform:

  • Apple Power MAC OS X using the GNU C Compiler

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