# OR-Library

OR-Library is a collection of test data sets for a variety of OR problems.

A full list of the test data sets available in OR-Library can be found
here.

## Unconstrained binary quadratic programming

There are currently 7 data files.

These data files are the test problems used in the working paper:
"Heuristic algorithms for the unconstrained binary quadratic programming
problem" by J.E. Beasley available from here.

The problem as given in the data files below is to maximise the expression
sum{i=1,...,n} sum{j=1,...,n} q(i,j)x(i)x(j)
where n is the number of variables and q(i,j) is a symmetric matrix.
The x(i) {i=1,...,n} are the binary (zero-one) variables.

The test problems are the files:
bqpgka, bqp50, bqp100, bqp250, bqp500, bqp1000, bqp2500
The format of these data files is:
number of test problems
for each test problem in turn:
number of variables (n), number of non-zero elements in the q(i,j) matrix
for each non-zero element in turn:
i, j, q(i,j) {=q(j,i) as the matrix is symmetric}

File bqpgka corresponds to the problems solved in F. Glover, G.A. Kochenberger
and B. Alidaee, Adaptive memory tabu search for binary quadratic programs.
Management Science 44 (1998) 336-345.

The largest file is bqp2500 of size 44Mb (approximately)
The entire set of files is of size 57Mb (approximately).

Click here to access these files

OTHER SOURCES

Test problems can be found here