Journal of Physics A: Mathematical and Theoretical ( IF 2.0 ) Pub Date : 2020-10-15 , DOI: 10.1088/1751-8121/abb439 P A M Casares , M A Martin-Delgado
We introduce a new quantum optimization algorithm for dense linear programming problems, which can be seen as the quantization of the interior point predictor–corrector algorithm [1] using a quantum linear system algorithm [2]. The (worst case) work complexity of our method is, up to polylogarithmic factors, for n the number of variables in the cost function, m the number of constraints, ϵ −1 the target precision, L the bit length of the input data, an upper bound to the Frobenius norm of the linear systems of equations that appear, ‖M‖F, and an upper bound to the condition number κ of those systems of equations. This represents a quantum speed-up in the number n of variables in the cost function with respect to the comparable classical interior point algorithms when the initial matrix of the problem A is dense: if we substitute the quantum part of the algorithm by classical algorithms such as conjugate gradient descent, that would mean the whole algorithm has complexity , or with exact methods, at least . Also, in contrast with any quantum linear system algorithm, the algorithm described in this article outputs a classical description of the solution vector, and the value of the optimal solution.
中文翻译:
一种用于线性规划的量子内点预测-校正算法
我们为密集线性规划问题引入了一种新的量子优化算法,可以看作是使用量子线性系统算法 [2] 对内点预测-校正算法 [1] 进行量化。我们方法的(最坏情况)工作复杂度是多对数因子,n是成本函数中的变量数,m是约束数,ε -1是目标精度,L是输入数据的位长,出现的线性方程组的 Frobenius 范数的上限 ‖ M ‖ F,以及条件数κ的上限那些方程组。这表示当问题A的初始矩阵密集时,成本函数中变量的数量n相对于可比较的经典内点算法的量子加速:如果我们用经典算法替换算法的量子部分,例如作为共轭梯度下降,这意味着整个算法具有复杂性,或者至少具有精确的方法。此外,与任何量子线性系统算法相比,本文描述的算法输出解向量的经典描述,以及最优解的值。