The following files contain problems we are interested in solving. Each describes what is called an "Ising model" in physics, and can be used to reconstruct a graph. The first line of a .txt file contains three numbers: the first number indicates how many variables (qubits) we have. The second number shows the number of lines that follow the first line. The third number is the ground state energy of the system.

Each following line also contains three numbers. The first and second numbers indicate two nodes in the Ising model. The third number is a weight. If the two nodes are different, then the weight applies to the edge between the nodes (J values in D-Wave's terminology). However, if the nodes are the same, the weight is applied to the corresponding node (h values).

Here is an example:

8 24 -4.234
1 5 0.428571
1 6 0.571429
1 7 -0.428571
1 8 0.571429
2 5 0.142857
2 6 -0.571429
2 7 -0.285714
2 8 0.000000
3 5 0.714286
3 6 0.714286
3 7 -0.428571
3 8 0.714286
4 5 0.714286
4 6 0.000000
4 7 0.285714
4 8 -0.428571
1 1 -0.142857
2 2 0.571429
3 3 0.285714
4 4 0.714286
5 5 0.142857
6 6 -0.714286
7 7 0.428571
8 8 0.571429

The above describes an 8-qubit problem. The second line indicates that nodes (qubits) 1 and 5 are connected together, and the weight of the connection is 0.428571. Qubit 1 has the weight -0.142857.

It is easy to decipher the name of the files. In a file named 1_8_4_Ising_ndg.txt, "1" means this is instance number 1. "8" indicates that this is an 8 qubit problem. "4" means that 4 precision bits are used to represent the weights, while "ndg" stands for non-degenerate, meaning that there is a unique ground state for this problem.

The .dat files contain equivalent information, but in a different format, more suitable for Quadratic Programming purposes. The .sol files contain the ground energy solution to the corresponding problem.