Το work with title Efficient computation of the binary vector that maximizes a rank-deficient quadratic form by Karystinos Georgios, Liavas Athanasios is licensed under Creative Commons Attribution 4.0 International
Bibliographic Citation
G. N. Karystinos and A. P. Liavas, “Efficient computation of the binary vector that maximizes a rank-deficient quadratic form,” IEEE Transactions on Information Theory, vol. 56, no. 7, pp. 3581 - 3593, Jul. 2010. doi: 10.1109/TIT.2010.2048450
https://doi.org/10.1109/TIT.2010.2048450
The maximization of a full-rank quadratic form over the binary alphabet can be performed through exponential-complexity exhaustive search. However, if the rank of the form is not a function of the problem size, then it can be maximized in polynomial time. By introducing auxiliary spherical coordinates, we show that the rank-deficient quadratic-form maximization problem is converted into a double maximization of a linear form over a multidimensional continuous set, the multidimensional set is partitioned into a polynomial-size set of regions which are associated with distinct candidate binary vectors, and the optimal binary vector belongs to the polynomial-size set of candidate vectors. Thus, the size of the candidate set is reduced from exponential to polynomial. We also develop an algorithm that constructs the polynomial-size candidate set in polynomial time and show that it is fully parallelizable and rank-scalable. Finally, we demonstrate the efficiency of the proposed algorithm in the context of adaptive spreading code design.