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Polymer Physics
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pv-wave®  under Linux (Kubuntu, SuSE)
pv-wave by Visual Numerics under Kubuntu and SuSE Linux

Überblick

pv-wave® is a package containing a programming language, libraries and a graphical user interface that is focused on the evaluation of multidimensional scientific data developed by Visual Numerics (VNI). VNI only supports RedHat Linux, but the package can be made to work even under Kubuntu and SuSE Linux (I am using pv-wave since 1996 on SuSE and since 2007 on a Kubuntu platform).

Why pv-wave but not IDL? When I tested both the development environments in 1996, IDL had no mechanism to abstractly define data structures with late binding. Check, if it is now possible to create a package of programs which can cope with deliberate image sizes and by which it is possible to, e.g. shrink images or cut smaller images from a big image and to continue processing without having to modify the programs. The required abstract data type of an image with "x by y pixels" can elegantly be defined in pv-wave.

Admittedly, the representation of 3D images is not perfect. Big rotation angles make the axes flip. Nevertheless, compare the library functions! For example, a multidimensional extrapolation of functions can be realized in pv-wave with a few lines of code by application of "radial basis functions" included in the IMSL-library.

Why Linux but not Windows?

If you are generating 30 GB of data within 3 days of experiments, under Windows you will encounter many system crashs during automated data evaluation. Every crash stops evaluation, and you have to start again. Windows is instable, Linux is stable (after hard work of installation). Under Windows the response of the pv-wave system is considerably delayed: If you are supposed to widen or to move a circle by a mouse command you should not become impatient if you are using Windows. Count "twenty-one, twenty-two" — and there is the response. This is not acceptable for professionals.

SuSE 10.2 or (K)Ubuntu?

The DVD version of SuSE 10.2 still was superior to (K)ubuntu what installation of graphics drivers and response with respect to working on a remote machine is concerned (something that is not at all possible under Windows). In the meantime (K)ubuntu is installing graphics card drivers with the same ease as SuSE, and the updates of the openssh-server of SuSE slowed down SuSE, as well. Now there is no advantage anymore when working with a set-up machine.

(K)Ubuntu is easier to use, not only in the case of migration from Windows to Unix. Nevertheless, in its plain flavor it only offers a workstation with passive connection to the internet. Services from other computers can be used, but the workstation does not offer services to remote workstations. No server daemon is working. Frequently it is necessary and sufficient to post-install the ssh-server. When in 2007 I tried to post-install a firewall, the complete internet access became blocked, and I had 2 extra days of installation work. So now I refrain from installing a firewall with Kubuntu. The actual version of openssh-server ist very slow whenever an X-Windows-connection is set up (ssh -X ...). Certain relief is obtained by avoiding to bother the DNS with name resolution. This is achieved by entering the machines that shall be accessed in the file /etc/hosts. Then it still takes minutes until the first graphics windows of the remote computer is displayed on the screen, but after that it works in an acceptable manner, but with pain.

The most important advantage of (K)ubuntu is the fast and complete installation of programs from the "repositories" of the Debian system.

Finally, in 2008 I feel an advantage of Kubuntu as compared to SuSE. I prefer KDE — and, thus, Kubuntu instead of Ubuntu. The reason is that KDE is more intuitive to me, and that saves time in daily production: Whenever I have big scattering patterns (1024 x 1024), I klick the hide-button and the complete desktop is free for graphics. In Gnome two control bars must be hidden, and in order to manage this one has to browse handbooks.

SEGMENTATION VIOLATION

Neither pv-wave < 8.5 nor older versions of IDL can be used with recent versions of Linux: In March 2007 an update of the library libX11 has been published. After application of the corresponding patch, pv-wave and IDL crash and throw a "segmentation violation", as soon as a graphical window is used. The simple instruction

tv, dist(100)

triggers the crash. The best method to cure this shortcoming is an update to pv-wave 9.0. If one has to continue using an older version, there is only a painful brute-force method:

  • Backup all data
  • Install a Linux system from DVD with an X11 library not newer than libx11-6_1.0.3-6 (Kubuntu Dapper Drake, early versions of Kubuntu Edgy Eft, or SuSE 10.2
  • Switch off all system updates
  • Install pv-wave

Of course, this malfunction is a programmig error in pv-wave, IDL and several other commercial data evaluation packages. The procedure tv is calling a method of the X11 library with an incomplete parameter list. Only the newer versions of libX11 are testing the validity of the arguments, and if this test fails the program is halted throwing an exception.

Installation under Kubuntu 7.10 (Gutsy Gibbon)

Installation under older operating systems (only in German)

Successful working with pv-wave!

    Universität Hamburg - Chemie - TMC - Stribeck - pv-wave Search Deutsche Version
Updated 11 Feb 2008 by Norbert Stribeck    Impressum