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Electronic Colloquium on Computational Complexity

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All reports by Author Piotr Indyk:

TR15-076 | 28th April 2015
Mahdi Cheraghchi, Piotr Indyk

Nearly Optimal Deterministic Algorithm for Sparse Walsh-Hadamard Transform

For every fixed constant $\alpha > 0$, we design an algorithm for computing the $k$-sparse Walsh-Hadamard transform of an $N$-dimensional vector $x \in \mathbb{R}^N$ in time $k^{1+\alpha} (\log N)^{O(1)}$. Specifically, the algorithm is given query access to $x$ and computes a $k$-sparse $\tilde{x} \in \mathbb{R}^N$ satisfying $\|\tilde{x} - \hat{x}\|_1 \leq ... more >>>

TR11-171 | 15th December 2011
Piotr Indyk, Reut Levi, Ronitt Rubinfeld

Approximating and Testing $k$-Histogram Distributions in Sub-linear time

Revisions: 1

A discrete distribution $p$, over $[n]$, is a $k$-histogram if its probability distribution function can be
represented as a piece-wise constant function with $k$ pieces. Such a function
represented by a list of $k$ intervals and $k$ corresponding values. We consider
the following problem: given a collection of samples ... more >>>

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