In this paper, we have studied the problem of minimizing the ratio of two indefinite quadratic functions subject to a strictly convex quadratic constraint. First utilizing the relationship between fractional and parametric programming problems due to Dinkelbach, we reformulate the fractional problem as a univariate equation. To find the root of the univariate equation, the generalized Newton method is utilized that requires solving a nonconvex quadratic optimization problem at each iteration. A key difficulty with this problem is its nonconvexity. Using Lagrange duality, we show that this problem can be solved by solving a convex univariate minimization problem. Attainment of the global optimality conditions is discussed. Our preliminary numerical experiments on several randomly generated test problems show that, the new approach is much faster in finding the global optimal solution than the known semidefinite relaxation approach, especially when solving large scale problems.
fractional optimization, indefinite quadratic optimization, semidefinite relaxation, diagonalization, generalized Newton method
90C32, 90C26, 90C22