Search Results for author: Stephen Boyd

Found 55 papers, 37 papers with code

Exponentially Weighted Moving Models

2 code implementations11 Apr 2024 Eric Luxenberg, Stephen Boyd

We propose a general method for computing an approximation of EWMM, which requires storing only a window of a fixed number of past samples, and uses an additional quadratic term to approximate the loss associated with the data before the window.

Time Series

Finding Moving-Band Statistical Arbitrages via Convex-Concave Optimization

1 code implementation12 Feb 2024 Kasper Johansson, Thomas Schmelzer, Stephen Boyd

We propose a new method for finding statistical arbitrages that can contain more assets than just the traditional pair.

Markowitz Portfolio Construction at Seventy

1 code implementation10 Jan 2024 Stephen Boyd, Kasper Johansson, Ronald Kahn, Philipp Schiele, Thomas Schmelzer

More than seventy years ago Harry Markowitz formulated portfolio construction as an optimization problem that trades off expected return and risk, defined as the standard deviation of the portfolio returns.

Factor Fitting, Rank Allocation, and Partitioning in Multilevel Low Rank Matrices

1 code implementation30 Oct 2023 Tetiana Parshakova, Trevor Hastie, Eric Darve, Stephen Boyd

The second is rank allocation, where we choose the ranks of the blocks in each level, subject to the total rank having a given value, which preserves the total storage needed for the MLR matrix.

Specifying and Solving Robust Empirical Risk Minimization Problems Using CVXPY

no code implementations9 Jun 2023 Eric Luxenberg, Dhruv Malik, Yuanzhi Li, Aarti Singh, Stephen Boyd

We consider robust empirical risk minimization (ERM), where model parameters are chosen to minimize the worst-case empirical loss when each data point varies over a given convex uncertainty set.

A Simple Method for Predicting Covariance Matrices of Financial Returns

1 code implementation31 May 2023 Kasper Johansson, Mehmet Giray Ogut, Markus Pelger, Thomas Schmelzer, Stephen Boyd

We also test covariance predictors on downstream applications such as portfolio optimization methods that depend on the covariance matrix.

Portfolio Optimization

Joint Graph Learning and Model Fitting in Laplacian Regularized Stratified Models

1 code implementation4 May 2023 Ziheng Cheng, Junzi Zhang, Akshay Agrawal, Stephen Boyd

Laplacian regularized stratified models (LRSM) are models that utilize the explicit or implicit network structure of the sub-problems as defined by the categorical features called strata (e. g., age, region, time, forecast horizon, etc.

Few-Shot Learning Graph Clustering +3

A Light-Weight Multi-Objective Asynchronous Hyper-Parameter Optimizer

no code implementations15 Feb 2022 Gabriel Maher, Stephen Boyd, Mykel Kochenderfer, Cristian Matache, Dylan Reuter, Alex Ulitsky, Slava Yukhymuk, Leonid Kopman

We describe a light-weight yet performant system for hyper-parameter optimization that approximately minimizes an overall scalar cost function that is obtained by combining multiple performance objectives using a target-priority-limit scalarizer.

Portfolio Construction as Linearly Constrained Separable Optimization

2 code implementations9 Mar 2021 Nicholas Moehle, Jack Gindi, Stephen Boyd, Mykel Kochenderfer

Mean-variance portfolio optimization problems often involve separable nonconvex terms, including penalties on capital gains, integer share constraints, and minimum position and trade sizes.

Portfolio Optimization Optimization and Control Portfolio Management

Minimum-Distortion Embedding

1 code implementation3 Mar 2021 Akshay Agrawal, Alnur Ali, Stephen Boyd

Our software scales to data sets with millions of items and tens of millions of distortion functions.

Dimensionality Reduction

Portfolio Performance Attribution via Shapley Value

no code implementations11 Feb 2021 Nicholas Moehle, Stephen Boyd, Andrew Ang

We consider an investment process that includes a number of features, each of which can be active or inactive.

Attribute

Covariance Prediction via Convex Optimization

1 code implementation29 Jan 2021 Shane Barratt, Stephen Boyd

We consider the problem of predicting the covariance of a zero mean Gaussian vector, based on another feature vector.

Low Rank Forecasting

no code implementations29 Jan 2021 Shane Barratt, Yining Dong, Stephen Boyd

Our focus is on low rank forecasters, which break forecasting up into two steps: estimating a vector that can be interpreted as a latent state, given the past, and then estimating the future values of the time series, given the latent state estimate.

Time Series Time Series Analysis

Portfolio Construction Using Stratified Models

no code implementations11 Jan 2021 Jonathan Tuck, Shane Barratt, Stephen Boyd

In this paper we develop models of asset return mean and covariance that depend on some observable market conditions, and use these to construct a trading policy that depends on these conditions, and the current portfolio holdings.

Sample Efficient Reinforcement Learning with REINFORCE

no code implementations22 Oct 2020 Junzi Zhang, Jongho Kim, Brendan O'Donoghue, Stephen Boyd

Policy gradient methods are among the most effective methods for large-scale reinforcement learning, and their empirical success has prompted several works that develop the foundation of their global convergence theory.

Policy Gradient Methods reinforcement-learning +1

Learning Convex Optimization Models

1 code implementation7 Jun 2020 Akshay Agrawal, Shane Barratt, Stephen Boyd

A convex optimization model predicts an output from an input by solving a convex optimization problem.

regression

Multi-Period Liability Clearing via Convex Optimal Control

1 code implementation18 May 2020 Shane Barratt, Stephen Boyd

We consider the problem of determining a sequence of payments among a set of entities that clear (if possible) the liabilities among them.

Optimal Representative Sample Weighting

1 code implementation18 May 2020 Shane Barratt, Guillermo Angeris, Stephen Boyd

We consider the problem of assigning weights to a set of samples or data records, with the goal of achieving a representative weighting, which happens when certain sample averages of the data are close to prescribed values.

Fitting Laplacian Regularized Stratified Gaussian Models

1 code implementation4 May 2020 Jonathan Tuck, Stephen Boyd

We consider the problem of jointly estimating multiple related zero-mean Gaussian distributions from data.

Weather Forecasting

Differentiating through Log-Log Convex Programs

2 code implementations27 Apr 2020 Akshay Agrawal, Stephen Boyd

We use the adjoint of the derivative to implement differentiable log-log convex optimization layers in PyTorch and TensorFlow.

Optimization and Control

Convex Optimization Over Risk-Neutral Probabilities

1 code implementation5 Mar 2020 Shane Barratt, Jonathan Tuck, Stephen Boyd

We describe a number of convex optimization problems over the convex set of risk neutral price probabilities.

Fundamental bounds for scattering from absorptionless electromagnetic structures

1 code implementation1 Mar 2020 Rahul Trivedi, Guillermo Angeris, Logan Su, Stephen Boyd, Shanhui Fan, Jelena Vuckovic

We illustrate our bounding procedure by studying limits on the scattering cross-sections of dielectric and metallic particles in the absence of material losses.

Optics

A New Heuristic for Physical Design

1 code implementation13 Feb 2020 Guillermo Angeris, Jelena Vučković, Stephen Boyd

In a physical design problem, the designer chooses values of some physical parameters, within limits, to optimize the resulting field.

Optimization and Control Computational Physics Optics

Automatic Repair of Convex Optimization Problems

1 code implementation29 Jan 2020 Shane Barratt, Guillermo Angeris, Stephen Boyd

Given an infeasible, unbounded, or pathological convex optimization problem, a natural question to ask is: what is the smallest change we can make to the problem's parameters such that the problem becomes solvable?

Optimization and Control

Eigen-Stratified Models

1 code implementation27 Jan 2020 Jonathan Tuck, Stephen Boyd

This leads to a reduction, sometimes large, of model size when $m \leq n$ and $m \ll K$.

Learning Convex Optimization Control Policies

no code implementations L4DC 2020 Akshay Agrawal, Shane Barratt, Stephen Boyd, Bartolomeo Stellato

Common examples of such convex optimization control policies (COCPs) include the linear quadratic regulator (LQR), convex model predictive control (MPC), and convex control-Lyapunov or approximate dynamic programming (ADP) policies.

Model Predictive Control

Differentiable Convex Optimization Layers

1 code implementation NeurIPS 2019 Akshay Agrawal, Brandon Amos, Shane Barratt, Stephen Boyd, Steven Diamond, Zico Kolter

In this paper, we propose an approach to differentiating through disciplined convex programs, a subclass of convex optimization problems used by domain-specific languages (DSLs) for convex optimization.

Inductive Bias

Minimizing a Sum of Clipped Convex Functions

1 code implementation27 Oct 2019 Shane Barratt, Guillermo Angeris, Stephen Boyd

We consider the problem of minimizing a sum of clipped convex functions; applications include clipped empirical risk minimization and clipped control.

A General Optimization Framework for Dynamic Time Warping

2 code implementations30 May 2019 Dave Deriso, Stephen Boyd

We pose the choice of warping function as an optimization problem with several terms in the objective.

Dynamic Time Warping

Disciplined Quasiconvex Programming

1 code implementation2 May 2019 Akshay Agrawal, Stephen Boyd

We present a composition rule involving quasiconvex functions that generalizes the classical composition rule for convex functions.

Optimization and Control Mathematical Software

A Distributed Method for Fitting Laplacian Regularized Stratified Models

2 code implementations26 Apr 2019 Jonathan Tuck, Shane Barratt, Stephen Boyd

In a basic and traditional formulation a separate model is fit for each value of the categorical feature, using only the data that has the specific categorical value.

Differentiating Through a Cone Program

1 code implementation19 Apr 2019 Akshay Agrawal, Shane Barratt, Stephen Boyd, Enzo Busseti, Walaa M. Moursi

These correspond to computing an approximate new solution, given a perturbation to the cone program coefficients (i. e., perturbation analysis), and to computing the gradient of a function of the solution with respect to the coefficients.

Optimization and Control

Least Squares Auto-Tuning

1 code implementation10 Apr 2019 Shane Barratt, Stephen Boyd

Least squares is by far the simplest and most commonly applied computational method in many fields.

Computational Bounds For Photonic Design

1 code implementation30 Nov 2018 Guillermo Angeris, Jelena Vuckovic, Stephen Boyd

Physical design problems, such as photonic inverse design, are typically solved using local optimization methods.

Optics Optimization and Control Computational Physics

Stochastic Mirror Descent in Variationally Coherent Optimization Problems

no code implementations NeurIPS 2017 Zhengyuan Zhou, Panayotis Mertikopoulos, Nicholas Bambos, Stephen Boyd, Peter W. Glynn

In this paper, we examine a class of non-convex stochastic optimization problems which we call variationally coherent, and which properly includes pseudo-/quasiconvex and star-convex optimization problems.

Stochastic Optimization

OSQP: An Operator Splitting Solver for Quadratic Programs

2 code implementations21 Nov 2017 Bartolomeo Stellato, Goran Banjac, Paul Goulart, Alberto Bemporad, Stephen Boyd

We present a general purpose solver for convex quadratic programs based on the alternating direction method of multipliers, employing a novel operator splitting technique that requires the solution of a quasi-definite linear system with the same coefficient matrix at almost every iteration.

Optimization and Control

A Rewriting System for Convex Optimization Problems

1 code implementation13 Sep 2017 Akshay Agrawal, Robin Verschueren, Steven Diamond, Stephen Boyd

We describe a modular rewriting system for translating optimization problems written in a domain-specific language to forms compatible with low-level solver interfaces.

Optimization and Control Mathematical Software

On the convergence of mirror descent beyond stochastic convex programming

no code implementations18 Jun 2017 Zhengyuan Zhou, Panayotis Mertikopoulos, Nicholas Bambos, Stephen Boyd, Peter Glynn

In this paper, we examine the convergence of mirror descent in a class of stochastic optimization problems that are not necessarily convex (or even quasi-convex), and which we call variationally coherent.

Stochastic Optimization

Toeplitz Inverse Covariance-Based Clustering of Multivariate Time Series Data

no code implementations10 Jun 2017 David Hallac, Sagar Vare, Stephen Boyd, Jure Leskovec

We derive closed-form solutions to efficiently solve the two resulting subproblems in a scalable way, through dynamic programming and the alternating direction method of multipliers (ADMM), respectively.

Clustering Time Series +1

Multi-Period Trading via Convex Optimization

3 code implementations29 Apr 2017 Stephen Boyd, Enzo Busseti, Steven Diamond, Ronald N. Kahn, Kwangmoo Koh, Peter Nystrup, Jan Speth

The methods we describe in this paper can be thought of as good ways to exploit predictions, no matter how they are made.

Model Predictive Control

Network Inference via the Time-Varying Graphical Lasso

1 code implementation6 Mar 2017 David Hallac, Youngsuk Park, Stephen Boyd, Jure Leskovec

Many important problems can be modeled as a system of interconnected entities, where each entity is recording time-dependent observations or measurements.

Time Series Time Series Analysis

Dirty Pixels: Towards End-to-End Image Processing and Perception

1 code implementation23 Jan 2017 Steven Diamond, Vincent Sitzmann, Frank Julca-Aguilar, Stephen Boyd, Gordon Wetzstein, Felix Heide

As such, conventional imaging involves processing the RAW sensor measurements in a sequential pipeline of steps, such as demosaicking, denoising, deblurring, tone-mapping and compression.

Autonomous Driving Deblurring +10

Greedy Gaussian Segmentation of Multivariate Time Series

1 code implementation24 Oct 2016 David Hallac, Peter Nystrup, Stephen Boyd

We consider the problem of breaking a multivariate (vector) time series into segments over which the data is well explained as independent samples from a Gaussian distribution.

Optimization and Control

Saturating Splines and Feature Selection

no code implementations21 Sep 2016 Nicholas Boyd, Trevor Hastie, Stephen Boyd, Benjamin Recht, Michael Jordan

We extend the adaptive regression spline model by incorporating saturation, the natural requirement that a function extend as a constant outside a certain range.

Additive models feature selection

Disciplined Multi-Convex Programming

3 code implementations12 Sep 2016 Xinyue Shen, Steven Diamond, Madeleine Udell, Yuantao Gu, Stephen Boyd

A multi-convex optimization problem is one in which the variables can be partitioned into sets over which the problem is convex when the other variables are fixed.

Optimization and Control

Convex Optimization With Abstract Linear Operators

no code implementations ICCV 2015 Steven Diamond, Stephen Boyd

We introduce a convex optimization modeling framework that transforms a convex optimization problem expressed in a form natural and convenient for the user into an equivalent cone program in a way that preserves fast linear transforms in the original problem.

A Differential Equation for Modeling Nesterov's Accelerated Gradient Method: Theory and Insights

no code implementations4 Mar 2015 Weijie Su, Stephen Boyd, Emmanuel J. Candes

We derive a second-order ordinary differential equation (ODE) which is the limit of Nesterov's accelerated gradient method.

A Differential Equation for Modeling Nesterov’s Accelerated Gradient Method: Theory and Insights

no code implementations NeurIPS 2014 Weijie Su, Stephen Boyd, Emmanuel Candes

We derive a second-order ordinary differential equation (ODE), which is the limit of Nesterov’s accelerated gradient method.

Convex Optimization in Julia

1 code implementation17 Oct 2014 Madeleine Udell, Karanveer Mohan, David Zeng, Jenny Hong, Steven Diamond, Stephen Boyd

This paper describes Convex, a convex optimization modeling framework in Julia.

Generalized Low Rank Models

1 code implementation1 Oct 2014 Madeleine Udell, Corinne Horn, Reza Zadeh, Stephen Boyd

Here, we extend the idea of PCA to handle arbitrary data sets consisting of numerical, Boolean, categorical, ordinal, and other data types.

Clustering Denoising +1

Accuracy at the Top

no code implementations NeurIPS 2012 Stephen Boyd, Corinna Cortes, Mehryar Mohri, Ana Radovanovic

We introduce a new notion of classification accuracy based on the top $\tau$-quantile values of a scoring function, a relevant criterion in a number of problems arising for search engines.

General Classification

Distributed Large Scale Network Utility Maximization

no code implementations18 Jan 2009 Danny Bickson, Yoav Tock, Argyris Zymnis, Stephen Boyd, Danny Dolev

Using an empirical evaluation we show that our new method outperforms previous approaches, including the truncated Newton method and dual-decomposition methods.

Information Theory Distributed, Parallel, and Cluster Computing Information Theory Optimization and Control

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