Vaguery + approximation   5

[1108.1320] Compressed Matrix Multiplication
"Motivated by the problems of computing sample covariance matrices, and of transforming a collection of vectors to a basis where they are sparse, we present a simple algorithm that computes an approximation of the product of two n-by-n real matrices A and B.…"
approximation  algorithms  nudge-targets 
december 2011 by Vaguery
[1107.0385] An algorithm for autonomously plotting solution sets in the presence of turning points
"Plotting solution sets for particular equations may be complicated by the existence of turning points. Here we describe an algorithm which not only overcomes such problematic points, but does so in the most general of settings. Applications of the algorithm are highlighted through two examples: the first provides verification, while the second demonstrates a non-trivial application. The latter is followed by a thorough run-time analysis. While both examples deal with bivariate equations, it is discussed how the algorithm may be generalized for space curves in $R^{3}$."
visualization  mathematics  graphics  approximation  algorithms  nudge-targets 
october 2011 by Vaguery
[1006.3128] Fundamental Tradeoffs for Sparsity Pattern Recovery
"Recovery of the sparsity pattern (or support) of a sparse vector from a small number of noisy linear samples is a common problem that arises in signal processing and statistics. In the high dimensional setting, it is known that recovery with a vanishing fraction of errors is impossible if the sampling rate and per-sample signal-to-noise ratio (SNR) are finite constants independent of the length of the vector. In this paper, it is shown that recovery with an arbitrarily small but constant fraction of errors is, however, possible, and that in some cases a computationally simple thresholding estimator is near-optimal.…"
signal-processing  nudge-targets  information-theory  communication  numerical-methods  statistics  algorithms  approximation  heuristics 
june 2010 by Vaguery
[0805.1071] Submodular approximation: sampling-based algorithms and lower bounds
"We introduce several generalizations of classical computer science problems obtained by replacing simpler objective functions with general submodular functions. The new problems include submodular load balancing, which generalizes load balancing or minimum-makespan scheduling, submodular sparsest cut and submodular balanced cut, which generalize their respective graph cut problems, as well as submodular function minimization with a cardinality lower bound.…"
mathematics  optimization  algorithms  approximation  operations-research 
june 2010 by Vaguery
[1005.1860] Feature Selection Using Regularization in Approximate Linear Programs for Markov Decision Processes
"Approximate dynamic programming has been used successfully in a large variety of domains, but it relies on a small set of provided approximation features to calculate solutions reliably. Large and rich sets of features can cause existing algorithms to overfit because of a limited number of samples. We address this shortcoming using $L_1$ regularization in approximate linear programming. Because the proposed method can automatically select the appropriate richness of features, its performance does not degrade with an increasing number of features. These results rely on new and stronger sampling bounds for regularized approximate linear programs. We also propose a computationally efficient homotopy method. The empirical evaluation of the approach shows that the proposed method performs well on simple MDPs and standard benchmark problems."
nudge-targets  dynamic-programming  approximation  algorithms  control-systems  linear-programming 
may 2010 by Vaguery

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