Spin Glass Server
(This service is provided by COPhy and M. Jünger's group.)
This page offers a service to compute exact ground states of Ising spin glasses and partition functions of Potts glasses with many states.
Instances can be uploaded using this webinterface or our commandline client (for Unix/Linux based OS). The results are returned by email.
We recommend to use the commandline client for the submission of many instances.
The following geometries are supported:
 Ising spin glass on a:
 twodimensional planar quadratic lattice (free boundary in at least one direction)
 twodimensional quadratic lattice on a torus (periodic boundaries in both directions)
 threedimensional lattice (periodic boundaries in all directions)
 complete graph (SherringtonKirkpatrick (SK) spinglass model). For the SK model, we use an algorithm provided to us by our colleagues G. Rinaldi, F. Rendl and A. Wiegele.
 Dominant contribution in partition function for Potts glasses with many states (on all graph types).
Submit your file(s) ...
(each instance has to be a text file; files can be bundled into an archive; supported archiveformats are tar, tar.gz and zip)
The input format is as follows:
name: the name of the instance
spin_i1 spin_j1 coupling between i1 and j1
spin_i2 spin_j2 coupling between i2 and j2
...
If the instance should be named like the filename, simply skip the line
name: ...
in the file.Lattices with uniformly distributed ±J couplings need to be scaled to ±1 couplings.
See an example of the input format together with the corresponding results from the server here.
For lattice models, spins are numbered sequentially layer by layer starting with index 1.
For example, a twodimensional 3x3 spin glass is numbered as follows:



(1)(2)(3)
  
(4)(5)(6)
  
(7)(8)(9)
  
For the nonlattice models such as the SherringtonKirkpatrick (SK) model, the order of the spins is arbitrary.(1)(2)(3)
  
(4)(5)(6)
  
(7)(8)(9)
  
If you have any special request or problems, please contact us directly: spinglass AT informatik.unikoeln.de
A more general instance generator can be downloaded here.