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arXiv 1608.02549stat.MLcs.ITmath.IT
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正交最小二乘稀疏线性回归的抽样要求和加速方案

Sampling Requirements and Accelerated Schemes for Sparse Linear Regression with Orthogonal Least-Squares

Abolfazl Hashemi, Haris Vikalo

摘要:

我们研究的问题推断稀疏向量的随机线性组合的组件。我们提出了加速正交最小二乘(AOLS)算法,提高了性能的著名的正交最小二乘(OLS)算法,同时需要显着降低计算成本。虽然OLS粗略地选择对应于稀疏向量的非零分量的系数矩阵的列,但AOLS采用新颖的计算上有效的过程,其通过在每个步骤中选择$L$列来预测未来的选择来加速搜索,其中$L$是可调整的超参数。我们分析了AOLS的性能,并建立了无噪声和有噪声的随机线性测量的精确恢复概率的下限。在无噪声的情况下,它示出,当系数是从高斯分布的样本,AOLS具有高概率恢复$k$ -稀疏$m$维稀疏向量使用${\cal O}(k\log \frac{m}{k+L-1})$测量。类似的结果是建立有界噪声的情况下,需要一个额外的条件上的最小非零元素的未知向量。AOLS的渐近采样复杂度低于现有稀疏重建算法的渐近采样复杂度。在模拟中,AOLS相比,国家的最先进的稀疏恢复技术,并显示提供更好的性能,在精度,运行时间,或两者兼而有之。最后,我们考虑了AOLS的应用聚类高维数据躺在低维子空间的联合,并证明了其优于现有的方法。

英文摘要:

We study the problem of inferring a sparse vector from random linear combinations of its components. We propose the Accelerated Orthogonal Least-Squares (AOLS) algorithm that improves performance of the well-known Orthogonal Least-Squares (OLS) algorithm while requiring significantly lower computational costs. While OLS greedily selects columns of the coefficient matrix that correspond to non-zero components of the sparse vector, AOLS employs a novel computationally efficient procedure that speeds up the search by anticipating future selections via choosing $L$ columns in each step, where $L$ is an adjustable hyper-parameter. We analyze the performance of AOLS and establish lower bounds on the probability of exact recovery for both noiseless and noisy random linear measurements. In the noiseless scenario, it is shown that when the coefficients are samples from a Gaussian distribution, AOLS with high probability recovers a $k$-sparse $m$-dimensional sparse vector using ${\cal O}(k\log \frac{m}{k+L-1})$ measurements. Similar result is established for the bounded-noise scenario where an additional condition on the smallest nonzero element of the unknown vector is required. The asymptotic sampling complexity of AOLS is lower than the asymptotic sampling complexity of the existing sparse reconstruction algorithms. In simulations, AOLS is compared to state-of-the-art sparse recovery techniques and shown to provide better performance in terms of accuracy, running time, or both. Finally, we consider an application of AOLS to clustering high-dimensional data lying on the union of low-dimensional subspaces and demonstrate its superiority over existing methods.

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