An improved quadratic program for unweighted Euclidean 1-center location problem

In this paper, an improved quadratic programing formulation for the solution of unweighted euclidean 1-center location problem is presented. the original quadratic program is proposed by nair and chandrasekaran in 1971. besides, they proposed a geometric approach for problem solving. then, they concluded that the geometric approach is more efficient than the quadratic program. this conclusion is true only when all decision variables are treated as nonnegative variables. to improve the quadratic program, one of those variables should be an unrestricted variable as it is presented here. numerically we proved that the improved quadratic program leads to the optimal solution of the problem in parts of second regardless of the size of the problem. moreover, constrained version of the problem is solved optimally via the improved quadratic program in parts of second