Dear all, There was indeed a problem in the version 2.0.0-4 of the alps2 Ubuntu Lucid 10.4 package. S. Aicardy wrote:

The trouble was caused by the RPATH linking in the package which forced the tebd program to use a wrong version of lapack. In Ubuntu 10.10 the problem didn't exist because there is only one version of lapack available.

The new version 2.0.0-5 of that package has corrected this bug. Many thanks to Michael Wall & Stephane Aicardi for their help. Gregoire Misguich. Le 27/01/2011 15:14, Grégoire Misguich a écrit :

Dear ALPS community,

As my first attempt to use the TEBD code provided in alps-2.0, I ran a tutorial concerning the simulation of the XX spin chain (tutorial_2a.py), which simulates the dynamics starting from a domain wall spin configuration:

http://alps.comp-phys.org/mediawiki/index.php/ALPS_2_Tutorials:TEBD-02_kink

I got the following figures (attached .png files).

The Wiki says "We see that the magnetization agrees very well to visual accuracy", but in the plot I obtained, it is not quite the case (very "noisy"). I played a bit with some parameters (increasing the number of time steps and the max Schmidt dimension), but it still get some ugly curves.

So, I suspect that something might we wrong...

Any help or suggestion would be very much appreciated !

Gregoire Misguich.