Entangled Mean Estimation in High-Dimensions
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arXiv
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| Format: | Preprint |
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2025
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| _version_ | 1866909452982026240 |
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| author | Diakonikolas, Ilias Kane, Daniel M. Liu, Sihan Pittas, Thanasis |
| author_facet | Diakonikolas, Ilias Kane, Daniel M. Liu, Sihan Pittas, Thanasis |
| contents | We study the task of high-dimensional entangled mean estimation in the subset-of-signals model. Specifically, given $N$ independent random points $x_1,\ldots,x_N$ in $\mathbb{R}^D$ and a parameter $α\in (0, 1)$ such that each $x_i$ is drawn from a Gaussian with mean $μ$ and unknown covariance, and an unknown $α$-fraction of the points have identity-bounded covariances, the goal is to estimate the common mean $μ$. The one-dimensional version of this task has received significant attention in theoretical computer science and statistics over the past decades. Recent work [LY20; CV24] has given near-optimal upper and lower bounds for the one-dimensional setting. On the other hand, our understanding of even the information-theoretic aspects of the multivariate setting has remained limited.
In this work, we design a computationally efficient algorithm achieving an information-theoretically near-optimal error. Specifically, we show that the optimal error (up to polylogarithmic factors) is $f(α,N) + \sqrt{D/(αN)}$, where the term $f(α,N)$ is the error of the one-dimensional problem and the second term is the sub-Gaussian error rate. Our algorithmic approach employs an iterative refinement strategy, whereby we progressively learn more accurate approximations $\hat μ$ to $μ$. This is achieved via a novel rejection sampling procedure that removes points significantly deviating from $\hat μ$, as an attempt to filter out unusually noisy samples. A complication that arises is that rejection sampling introduces bias in the distribution of the remaining points. To address this issue, we perform a careful analysis of the bias, develop an iterative dimension-reduction strategy, and employ a novel subroutine inspired by list-decodable learning that leverages the one-dimensional result. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2501_05425 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Entangled Mean Estimation in High-Dimensions Diakonikolas, Ilias Kane, Daniel M. Liu, Sihan Pittas, Thanasis Data Structures and Algorithms Machine Learning Statistics Theory We study the task of high-dimensional entangled mean estimation in the subset-of-signals model. Specifically, given $N$ independent random points $x_1,\ldots,x_N$ in $\mathbb{R}^D$ and a parameter $α\in (0, 1)$ such that each $x_i$ is drawn from a Gaussian with mean $μ$ and unknown covariance, and an unknown $α$-fraction of the points have identity-bounded covariances, the goal is to estimate the common mean $μ$. The one-dimensional version of this task has received significant attention in theoretical computer science and statistics over the past decades. Recent work [LY20; CV24] has given near-optimal upper and lower bounds for the one-dimensional setting. On the other hand, our understanding of even the information-theoretic aspects of the multivariate setting has remained limited. In this work, we design a computationally efficient algorithm achieving an information-theoretically near-optimal error. Specifically, we show that the optimal error (up to polylogarithmic factors) is $f(α,N) + \sqrt{D/(αN)}$, where the term $f(α,N)$ is the error of the one-dimensional problem and the second term is the sub-Gaussian error rate. Our algorithmic approach employs an iterative refinement strategy, whereby we progressively learn more accurate approximations $\hat μ$ to $μ$. This is achieved via a novel rejection sampling procedure that removes points significantly deviating from $\hat μ$, as an attempt to filter out unusually noisy samples. A complication that arises is that rejection sampling introduces bias in the distribution of the remaining points. To address this issue, we perform a careful analysis of the bias, develop an iterative dimension-reduction strategy, and employ a novel subroutine inspired by list-decodable learning that leverages the one-dimensional result. |
| title | Entangled Mean Estimation in High-Dimensions |
| topic | Data Structures and Algorithms Machine Learning Statistics Theory |
| url | https://arxiv.org/abs/2501.05425 |