National Physical Laboratory

  • Science + Technology

    Science + Technology

    NPL maintains a wide portfolio of internationally visible research programmes that advances measurement science, underpins the SI system and supports various cross-disciplinary technologies.

    Science stories

    • Measurement in 2020

      Kamal Hossain, Director of Research and International, outlines in QMT magazine, how NPL is rising to meet the measurement challenges of the next two decades.
      More

    • Order from disorder

      Collaborative research into a protein associated with Parkinson’s disease explores a novel way of organising proteins at the nanoscale.
      More

    • Radiotherapy doses to be more accurate

      Collaborative research on the distribution of charged particles during treatment will contribute to safer radiotherapy for cancer patients.
      More

    • The tick-tock of the optical clock

      A new frequency measurement in an ytterbium ion could form the basis for the next generation of optical atomic clocks.
      More
  • Commercial Services

    Commercial Services

    NPL's commercial services are built on 100 years of leadership in accuracy, innovation and scientific research. Experienced consultants and project managers draw upon a unique combination of industry know-how and world-leading scientific discovery to deliver real-world business solutions and enable innovation and secure competitive advantage.

    Testimonials

    • Bentley Logo

      Thanks to NPL Training, the measurement associates are now thinking out of the box. We are already seeing a faster turnaround of measurement activities with higher accuracy and increased confidence. NPL is known for its technical expertise in this area, and can provide the highest level validated training. It's added to our professionalism and improved communication with our suppliers.

      Mark Imms
      Metrology Manager
      Bentley Motors

    • surreysat2

      NPL has provided us with very valuable services, which have helped ensure that our satellites offer the accuracy needed provide our customers with technology they can trust, and remain ahead of our competitors.

      Dr Martin Unwin
      Head of GNSS/GPS Team
      Surrey Satellite Technology Ltd

    • bpGif



      BP Exploration has continued to benefit from NPL's world class corrosion testing and modelling capabilities in 2009, and we intend to cooperate even more closely in 2010 and beyond.

      Steve Groves
      Programmes Manager
      Inherently Reliable Facilities Flagship BP
  • Educate + Explore

    Educate + Explore

    We strive to actively promote public awareness and appreciation of science and technology, particularly the importance of measurement and the role of NPL. Here you can find out more about the interesting things we do, science outreach activities you can get involved in or take a look at some of our educational resources.

    Outreach Activities

  • NMS Learning Zone
  • Measurement Network

    Measurement Network

    The Measurement Network is the UK’s national network set up to support businesses to solve measurement challenges, increase the spread and adoption of measurement knowledge and address strategic measurement issues.

  • View Full
    Menu

    About NPL

    News + Events

    Publications

    Contact

Repositories of Software

The last four decades have been ones of great success in terms of the development of reliable algorithms for solving the most common computational problems. In the fields of numerical linear algebra – linear equations, linear least squares, eigenvalues, matrix factorisations — and optimisation — nonlinear equations, nonlinear least squares, minimisation subject to constraints, linear programming, nonlinear programming — there is now a substantial core of software modules which the metrologist can exploit.

The scientist has a range of sources for software:

  1. specialist software developers/collectors such as the NAG library in the UK and IMSL in the US,
  2. National laboratories, for example NPL, Harwell, Argonne, Oakridge,
  3. universities,
  4. industrial laboratories,
  5. software houses, and
  6. instrument manufacturers.

Library software, used by many scientists and continually maintained, provides perhaps the best guarantee of reliability.

Library software

Libraries which have routines relevant to the metrologist:

  • NAG:  A large Fortran Library1 covering most of the computational disciplines including quadrature, ordinary differential equations, partial differential equations, integral equations, interpolation, curve and surface fitting, optimisation, linear algebra (simultaneous linear equations, matrix factorisations, eigenvalues), correlation and regression analysis, analysis of variance and non-parametric statistics.
  • IMSL: International Mathematical and Statistical Libraries, Inc. Similar to NAG but based in the US.
  • LINPACK: A Fortran library for solving systems of linear equations, including least-squares systems, developed at Argonne National Laboratory (ANL), USA.
  • EISPACK: A companion library to LINPACK for solving eigenvalue problems also developed at ANL.
  • LAPACK: A replacement for, and further development of, LINPACK and EISPACK. LAPACK also appears as a sub-chapter of the NAG library.
  • Harwell: Optimisation routines including those for large and/or sparse problems.
  • DASL: Data Approximation Subroutine Library, developed at NPL, for data interpolation and approximation with polynomial and spline curves and surfaces.
  • MINPACK: Another Fortran Library developed at ANL for function minimisation. MINPACK contains software for solving nonlinear least-squares problems.

A number of journals also publish the source codes for software. In particular the ACM Transactions on Mathematical Software has published over 700 algorithms for various types of computation. Applied Statistics publishes software for statistical computations.

Most library software has been written in Fortran 77, a language well suited to numerical computation but in other ways limited in comparison with more modern languages. The situation has changed radically with the advent of new versions of the language – Fortran 90/95 – which have all the features that Fortran 77 was perceived as lacking while maintaining full backwards compatibility. Using Fortran 90/95 to create dynamically linked libraries (DLLs), it is relatively straightforward to interface the numerical library software with spreadsheet packages on a PC, for example, or to software written in other languages. Many library subroutines now also appear in Fortran 90/95 implementations.

Scientific software packages

There are a number of scientific software packages, including Matlab, Mathematica, MathCad and S-Plus that are widely used by numerical mathematicians, scientists and engineer.

  • Netlib is a comprehensive range of mathematical software can be obtained over the Internet through Netlib. For example, the LINPACK, EISPACK, LAPACK and MINPACK libraries are available through Netlib along with the later algorithms published in ACM Transactions on Mathematical Software. The system is very easy to use and there are also browsing, news and literature search facilities.
  • Statlib is similar to Netlib but covers algorithms and software for statistical calculations.
  • Guide to Available Mathematical Software (GAMS) developed and maintained by the National Institute of Standards and Technology (NIST), Gaithersburg, MD, provides a comprehensive listing of mathematical software classified into subject areas such as linear algebra, optimisation, etc. It includes the software in Netlib and the NAG and IMSL libraries. Using the search facilities the user can quickly identify modules in the public domain or in commercial libraries.
  • e-Handbook of Statistical Methods published online by NIST/SEMATECH.

EUROMETROS

The resources we have listed so far relate to science in general rather than metrology in particular. Certainly, many of the problems in metrology are generic and it is sensible to apply general solutions where they are appropriate. The SSfM programme as a whole aims to bridge the gap between the best computational techniques and the needs of metrology with the main focus of bringing appropriate technology to the metrologist in a usable form.

The EUROMETROS metrology software repository (formerly MetroS) provides the metrologist easy access to modules performing the key functions for metrology. MetroS was developed as part of the Software re-use project of the first SSfM programme; in the second SSfM programme, it was renamed as EUROMETROS to reflect its relationship with the EUROMET organisation and AMCTM European thematic network.

The current content of EUROMETROS is predominantly routines for fitting empirical and geometric models to data, and routines associated with those models or with the fitting problems. These are mainly implementations developed by NPL in SSfM and previous programmes. EUROMETROS also describes functions and algorithms for metrology problems, test data sets for testing solutions to those problems, and reference material (best/good practice guides, papers, case study reports, etc.) related to software for metrology.

Links

Last Updated: 25 Mar 2010
Created: 5 Jun 2007