The version of the Concorde TSP code that was used in the Sweden computation was released in December 2003; the version number is 03.12.19.

Experimental versions of the LKH tour-finding code were used by Keld Helsgaun to obtain the 855,597 Sweden Tour.

The linear programming (LP) problems encountered in the Sweden computation were solved with the simplex method as implemented in the ILOG Cplex solver. In our computation we made use of Version 6.5 of Cplex. The solver interface is described in the file LP/lpcplex.c in the Concorde distribution.

Concorde's parallel implementation of branch-and-cut makes use of NFS sockets for machine communication; the source code for the communication functions is contained in the file UTIL/safe_io.c in the Concorde distribution. The shared-memory parallel cutserver makes use of the PThreads library; the source code can be found in the file TSP/cutpool.c.

The main Sweden computation was carried out on a cluster dual-processor Intel Xeon workstations running Red Hat Linux 9.0. Cut-pool servers were run on a shared-memory Sun Fire V480 running Sun Solaris 9.