Search Results for author:
Found 81 papers, 17 papers with code
Learning Mixtures of Experts with EM
There, the partitioning function and the experts are both learnt jointly via gradient descent on the log-likelihood.
Understanding Contrastive Learning via Gaussian Mixture Models
Contrastive learning attempts to learn representations from un-labeled data; it does so via a loss function that encourages the embedding of a point to be close to that of its augmentations, and far from the embeddings of random other points.
RARe: Retrieval Augmented Retrieval with In-Context Examples
Our approach, RARe, finetunes a pre-trained model with in-context examples whose query is semantically similar to the target query.
Geometric Median (GM) Matching for Robust Data Pruning
Moreover, these strategies often yield sub-optimal neural scaling laws even compared to random sampling, especially in scenarios involving strong corruption and aggressive pruning rates -- making provably robust data pruning an open challenge.
Retraining with Predicted Hard Labels Provably Increases Model Accuracy
In this paper, we theoretically analyze retraining in a linearly separable setting with randomly corrupted labels given to us and prove that retraining can improve the population accuracy obtained by initially training with the given (noisy) labels.
DataComp-LM: In search of the next generation of training sets for language models
We introduce DataComp for Language Models (DCLM), a testbed for controlled dataset experiments with the goal of improving language models.
Adaptive and Optimal Second-order Optimistic Methods for Minimax Optimization
We propose adaptive, line search-free second-order methods with optimal rate of convergence for solving convex-concave min-max problems.
SVFT: Parameter-Efficient Fine-Tuning with Singular Vectors
Extensive experiments on language and vision benchmarks show that SVFT recovers up to 96% of full fine-tuning performance while training only 0. 006 to 0. 25% of parameters, outperforming existing methods that only recover up to 85% performance using 0. 03 to 0. 8% of the trainable parameter budget.
Inheritune: Training Smaller Yet More Attentive Language Models
However, we observe that in standard decoder-style LLMs, attention matrices degenerate to single-column for deeper layers.
Time Weaver: A Conditional Time Series Generation Model
Current approaches to time series generation often ignore this paired metadata, and its heterogeneity poses several practical challenges in adapting existing conditional generation approaches from the image, audio, and video domains to the time series domain.
In-Context Learning with Transformers: Softmax Attention Adapts to Function Lipschitzness
We show that an attention unit learns a window that it uses to implement a nearest-neighbors predictor adapted to the landscape of the pretraining tasks.
Towards Quantifying the Preconditioning Effect of Adam
Specifically, for a $d$-dimensional quadratic with a diagonal Hessian having condition number $\kappa$, we show that the effective condition number-like quantity controlling the iteration complexity of Adam without momentum is $\mathcal{O}(\min(d, \kappa))$.
Understanding the Training Speedup from Sampling with Approximate Losses
In this work, we focus on the greedy approach of selecting samples with large \textit{approximate losses} instead of exact losses in order to reduce the selection overhead.
Contrastive Approach to Prior Free Positive Unlabeled Learning
Positive Unlabeled (PU) learning refers to the task of learning a binary classifier given a few labeled positive samples, and a set of unlabeled samples (which could be positive or negative).
Pretrained deep models outperform GBDTs in Learning-To-Rank under label scarcity
On tabular data, a significant body of literature has shown that current deep learning (DL) models perform at best similarly to Gradient Boosted Decision Trees (GBDTs), while significantly underperforming them on outlier data.
Finite-Time Logarithmic Bayes Regret Upper Bounds
In a multi-armed bandit, we obtain $O(c_\Delta \log n)$ and $O(c_h \log^2 n)$ upper bounds for an upper confidence bound algorithm, where $c_h$ and $c_\Delta$ are constants depending on the prior distribution and the gaps of bandit instances sampled from it, respectively.
Early Weight Averaging meets High Learning Rates for LLM Pre-training
Specifically, we pre-trained nanoGPT-2 models of varying sizes, small (125M), medium (335M), and large (770M)on the OpenWebText dataset, comprised of 9B tokens.
Understanding Self-Distillation in the Presence of Label Noise
Self-distillation (SD) is the process of first training a \enquote{teacher} model and then using its predictions to train a \enquote{student} model with the \textit{same} architecture.
Latent Variable Representation for Reinforcement Learning
Theoretically, we establish the sample complexity of the proposed approach in the online and offline settings.
Model-based Reinforcement Learning
reinforcement-learning
+2
Bayesian Fixed-Budget Best-Arm Identification
We also provide a lower bound on the probability of misidentification in a $2$-armed Bayesian bandit and show that our upper bound (almost) matches it for any budget.
Toward Understanding Privileged Features Distillation in Learning-to-Rank
Such features naturally arise in merchandised recommendation systems; for instance, "user clicked this item" as a feature is predictive of "user purchased this item" in the offline data, but is clearly not available during online serving.
On the Value of Behavioral Representations for Dense Retrieval
We consider text retrieval within dense representational space in real-world settings such as e-commerce search where (a) document popularity and (b) diversity of queries associated with a document have a skewed distribution.
Beyond Uniform Lipschitz Condition in Differentially Private Optimization
Most prior results on differentially private stochastic gradient descent (DP-SGD) are derived under the simplistic assumption of uniform Lipschitzness, i. e., the per-sample gradients are uniformly bounded.
Positive Unlabeled Contrastive Learning
We extend this paradigm to the classical positive unlabeled (PU) setting, where the task is to learn a binary classifier given only a few labeled positive samples, and (often) a large amount of unlabeled samples (which could be positive or negative).
Beyond EM Algorithm on Over-specified Two-Component Location-Scale Gaussian Mixtures
However, when the models are over-specified, namely, the chosen number of components to fit the data is larger than the unknown true number of components, EM needs a polynomial number of iterations in terms of the sample size to reach the final statistical radius; this is computationally expensive in practice.
An Exponentially Increasing Step-size for Parameter Estimation in Statistical Models
Therefore, the total computational complexity of the EGD algorithm is \emph{optimal} and exponentially cheaper than that of the GD for solving parameter estimation in non-regular statistical models while being comparable to that of the GD in regular statistical settings.
Minimax Regret for Cascading Bandits
Cascading bandits is a natural and popular model that frames the task of learning to rank from Bernoulli click feedback in a bandit setting.
Sample Efficiency of Data Augmentation Consistency Regularization
Data augmentation is popular in the training of large neural networks; currently, however, there is no clear theoretical comparison between different algorithmic choices on how to use augmented data.
Improving Computational Complexity in Statistical Models with Second-Order Information
This computational complexity is cheaper than that of the fixed step-size gradient descent algorithm, which is of the order $\mathcal{O}(n^{\tau})$ for some $\tau > 1$, to reach the same statistical radius.
Towards Statistical and Computational Complexities of Polyak Step Size Gradient Descent
We study the statistical and computational complexities of the Polyak step size gradient descent algorithm under generalized smoothness and Lojasiewicz conditions of the population loss function, namely, the limit of the empirical loss function when the sample size goes to infinity, and the stability between the gradients of the empirical and population loss functions, namely, the polynomial growth on the concentration bound between the gradients of sample and population loss functions.
Theoretical Analysis of Consistency Regularization with Limited Augmented Data
Data augmentation is popular in the training of large neural networks; currently, however, there is no clear theoretical comparison between different algorithmic choices on how to use augmented data.
Robust Training in High Dimensions via Block Coordinate Geometric Median Descent
Geometric median (\textsc{Gm}) is a classical method in statistics for achieving a robust estimation of the uncorrupted data; under gross corruption, it achieves the optimal breakdown point of 0. 5.
Ranked #22 on
Image Classification
on MNIST
(Accuracy metric)
On the Convergence of Differentially Private Federated Learning on Non-Lipschitz Objectives, and with Normalized Client Updates
The primary reason for this is that the clipping operation (i. e., projection onto an $\ell_2$ ball of a fixed radius called the clipping threshold) for bounding the sensitivity of the average update to each client's update introduces bias depending on the clipping threshold and the number of local steps in FL, and analyzing this is not easy.
Enabling Efficiency-Precision Trade-offs for Label Trees in Extreme Classification
For such applications, a common approach is to organize these labels into a tree, enabling training and inference times that are logarithmic in the number of labels.
Nearly Horizon-Free Offline Reinforcement Learning
To the best of our knowledge, these are the \emph{first} set of nearly horizon-free bounds for episodic time-homogeneous offline tabular MDP and linear MDP with anchor points.
Linear Bandit Algorithms with Sublinear Time Complexity
For sufficiently large $K$, our algorithms have sublinear per-step complexity and $\tilde O(\sqrt{T})$ regret.
Combinatorial Bandits without Total Order for Arms
Specifically, we focus on a challenging setting where 1) the reward distribution of an arm depends on the set $s$ it is part of, and crucially 2) there is \textit{no total order} for the arms in $\mathcal{A}$.
Faster Non-Convex Federated Learning via Global and Local Momentum
We propose \texttt{FedGLOMO}, a novel federated learning (FL) algorithm with an iteration complexity of $\mathcal{O}(\epsilon^{-1. 5})$ to converge to an $\epsilon$-stationary point (i. e., $\mathbb{E}[\|\nabla f(\bm{x})\|^2] \leq \epsilon$) for smooth non-convex functions -- under arbitrary client heterogeneity and compressed communication -- compared to the $\mathcal{O}(\epsilon^{-2})$ complexity of most prior works.
On Generalization of Adaptive Methods for Over-parameterized Linear Regression
In this paper, we aim to characterize the performance of adaptive methods in the over-parameterized linear regression setting.
On the Benefits of Multiple Gossip Steps in Communication-Constrained Decentralized Optimization
In this paper, we show that, in such compressed decentralized optimization settings, there are benefits to having {\em multiple} gossip steps between subsequent gradient iterations, even when the cost of doing so is appropriately accounted for e. g. by means of reducing the precision of compressed information.
Extreme Multi-label Classification from Aggregated Labels
Current XMC approaches are not built for such multi-instance multi-label (MIML) training data, and MIML approaches do not scale to XMC sizes.
Choosing the Sample with Lowest Loss makes SGD Robust
The presence of outliers can potentially significantly skew the parameters of machine learning models trained via stochastic gradient descent (SGD).
Interaction Hard Thresholding: Consistent Sparse Quadratic Regression in Sub-quadratic Time and Space
In this paper, we provide a new algorithm - Interaction Hard Thresholding (IntHT) which is the first one to provably accurately solve this problem in sub-quadratic time and space.
Learning Distributions Generated by One-Layer ReLU Networks
We give a simple algorithm to estimate the parameters (i. e., the weight matrix and bias vector of the ReLU neural network) up to an error $\epsilon||W||_F$ using $\tilde{O}(1/\epsilon^2)$ samples and $\tilde{O}(d^2/\epsilon^2)$ time (log factors are ignored for simplicity).
Blocking Bandits
We show that with prior knowledge of the rewards and delays of all the arms, the problem of optimizing cumulative reward does not admit any pseudo-polynomial time algorithm (in the number of arms) unless randomized exponential time hypothesis is false, by mapping to the PINWHEEL scheduling problem.
Iterative Least Trimmed Squares for Mixed Linear Regression
We then evaluate it for the widely studied setting of isotropic Gaussian features, and establish that we match or better existing results in terms of sample complexity.
PruneTrain: Fast Neural Network Training by Dynamic Sparse Model Reconfiguration
State-of-the-art convolutional neural networks (CNNs) used in vision applications have large models with numerous weights.
Minimum weight norm models do not always generalize well for over-parameterized problems
We empirically show that the minimum weight norm is not necessarily the proper gauge of good generalization in simplified scenaria, and different models found by adaptive methods could outperform plain gradient methods.
Sparse Logistic Regression Learns All Discrete Pairwise Graphical Models
We show that this algorithm can recover any arbitrary discrete pairwise graphical model, and also characterize its sample complexity as a function of model width, alphabet size, edge parameter accuracy, and the number of variables.
Learning with Bad Training Data via Iterative Trimmed Loss Minimization
In this paper, we study a simple and generic framework to tackle the problem of learning model parameters when a fraction of the training samples are corrupted.
Iteratively Learning from the Best
We study a simple generic framework to address the issue of bad training data; both bad labels in supervised problems, and bad samples in unsupervised ones.
Learning a Compressed Sensing Measurement Matrix via Gradient Unrolling
Our experiments show that there is indeed additional structure beyond sparsity in the real datasets; our method is able to discover it and exploit it to create excellent reconstructions with fewer measurements (by a factor of 1. 1-3x) compared to the previous state-of-the-art methods.
Sparse Quadratic Logistic Regression in Sub-quadratic Time
We consider support recovery in the quadratic logistic regression setting - where the target depends on both p linear terms $x_i$ and up to $p^2$ quadratic terms $x_i x_j$.
Normalized Spectral Map Synchronization
The algorithmic advancement of synchronizing maps is important in order to solve a wide range of practice problems with possible large-scale dataset.
Single Pass PCA of Matrix Products
In this paper we present a new algorithm for computing a low rank approximation of the product $A^TB$ by taking only a single pass of the two matrices $A$ and $B$.
The Search Problem in Mixture Models
We consider the task of learning the parameters of a {\em single} component of a mixture model, for the case when we are given {\em side information} about that component, we call this the "search problem" in mixture models.
Non-square matrix sensing without spurious local minima via the Burer-Monteiro approach
We consider the non-square matrix sensing problem, under restricted isometry property (RIP) assumptions.
Solving a Mixture of Many Random Linear Equations by Tensor Decomposition and Alternating Minimization
We give a tractable algorithm for the mixed linear equation problem, and show that under some technical conditions, our algorithm is guaranteed to solve the problem exactly with sample complexity linear in the dimension, and polynomial in $k$, the number of components.
Finding Low-Rank Solutions via Non-Convex Matrix Factorization, Efficiently and Provably
We study such parameterization for optimization of generic convex objectives $f$, and focus on first-order, gradient descent algorithmic solutions.
Provable Burer-Monteiro factorization for a class of norm-constrained matrix problems
We study the projected gradient descent method on low-rank matrix problems with a strongly convex objective.
Trading-off variance and complexity in stochastic gradient descent
Stochastic gradient descent is the method of choice for large-scale machine learning problems, by virtue of its light complexity per iteration.
Convergence rates of sub-sampled Newton methods
Provided certain conditions hold on the model class, we provide a two-stage active learning algorithm for this problem.
Dropping Convexity for Faster Semi-definite Optimization
To the best of our knowledge, this is the first paper to provide precise convergence rate guarantees for general convex functions under standard convex assumptions.
Preference Completion: Large-scale Collaborative Ranking from Pairwise Comparisons
In this paper we consider the collaborative ranking setting: a pool of users each provides a small number of pairwise preferences between $d$ possible items; from these we need to predict preferences of the users for items they have not yet seen.
The local convexity of solving systems of quadratic equations
This paper considers the recovery of a rank $r$ positive semidefinite matrix $X X^T\in\mathbb{R}^{n\times n}$ from $m$ scalar measurements of the form $y_i := a_i^T X X^T a_i$ (i. e., quadratic measurements of $X$).
Convergence Rates of Active Learning for Maximum Likelihood Estimation
Provided certain conditions hold on the model class, we provide a two-stage active learning algorithm for this problem.
A New Sampling Technique for Tensors
In this paper we propose new techniques to sample arbitrary third-order tensors, with an objective of speeding up tensor algorithms that have recently gained popularity in machine learning.
Online Collaborative-Filtering on Graphs
We consider this problem under a simple natural model, wherein the number of items and the number of item-views are of the same order, and an `access-graph' constrains which user is allowed to see which item.
Greedy Subspace Clustering
We consider the problem of subspace clustering: given points that lie on or near the union of many low-dimensional linear subspaces, recover the subspaces.
Non-convex Robust PCA
In contrast, existing methods for robust PCA, which are based on convex optimization, have $O(m^2n)$ complexity per iteration, and take $O(1/\epsilon)$ iterations, i. e., exponentially more iterations for the same accuracy.
Tighter Low-rank Approximation via Sampling the Leveraged Element
The first is a new method to directly compute a low-rank approximation (in efficient factored form) to the product of two given matrices; it computes a small random set of entries of the product, and then executes weighted alternating minimization (as before) on these.
Alternating Minimization for Mixed Linear Regression
Mixed linear regression involves the recovery of two (or more) unknown vectors from unlabeled linear measurements; that is, where each sample comes from exactly one of the vectors, but we do not know which one.
Completing Any Low-rank Matrix, Provably
Matrix completion, i. e., the exact and provable recovery of a low-rank matrix from a small subset of its elements, is currently only known to be possible if the matrix satisfies a restrictive structural constraint---known as {\em incoherence}---on its row and column spaces.
Phase Retrieval using Alternating Minimization
Empirically, we demonstrate that alternating minimization performs similar to recently proposed convex techniques for this problem (which are based on "lifting" to a convex matrix problem) in sample complexity and robustness to noise.
Clustering Sparse Graphs
We develop a new algorithm to cluster sparse unweighted graphs -- i. e. partition the nodes into disjoint clusters so that there is higher density within clusters, and low across clusters.
Improved Graph Clustering
We show that, in the classic stochastic block model setting, it outperforms existing methods by polynomial factors when the cluster size is allowed to have general scalings.
Clustering Partially Observed Graphs via Convex Optimization
This paper considers the problem of clustering a partially observed unweighted graph---i. e., one where for some node pairs we know there is an edge between them, for some others we know there is no edge, and for the remaining we do not know whether or not there is an edge.
Matrix completion with column manipulation: Near-optimal sample-robustness-rank tradeoffs
Moreover, we show by an information-theoretic argument that our guarantees are nearly optimal in terms of the fraction of sampled entries on the authentic columns, the fraction of corrupted columns, and the rank of the underlying matrix.
A Dirty Model for Multi-task Learning
However, these papers also caution that the performance of such block-regularized methods are very dependent on the {\em extent} to which the features are shared across tasks.
Robust PCA via Outlier Pursuit
Singular Value Decomposition (and Principal Component Analysis) is one of the most widely used techniques for dimensionality reduction: successful and efficiently computable, it is nevertheless plagued by a well-known, well-documented sensitivity to outliers.
Linear programming analysis of loopy belief propagation for weighted matching
Loopy belief propagation has been employed in a wide variety of applications with great empirical success, but it comes with few theoretical guarantees.
