Many problems in statistical learning, imaging, and computer vision involve the optimization of a non-convex objective function with singularities at the boundary of the feasible set. For such challenging instances, we develop a new interior-point technique building on the Hessian-barrier algorithm recently introduced …
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Interior-point methods adapted for manifolds, achieving similar optimization results.
RHMC improves sampling polytopes defined by inequalities with barriers.
New method improves HMC for sampling on manifolds.
Unified analysis of online optimization with self-concordant barriers, improving regret bounds.
Many scientific and engineering applications feature nonsmooth convex minimization problems over convex sets. In this paper, we address an important instance of this broad class where we assume that the nonsmooth objective is equipped with a tractable proximity operator and that the convex constraint set affords a self…
Unified algorithm for linear bandits with improved regret bound.
We propose a randomized second-order method for optimization known as the Newton Sketch: it is based on performing an approximate Newton step using a randomly projected or sub-sampled Hessian. For self-concordant functions, we prove that the algorithm has super-linear convergence with exponentially high probability, wi…
Algorithm for online decision making with unknown dynamics and aggregate feedback.
New approach for online learning with adaptive adversaries, simpler and more effective.
Unified meta-algorithm improves average performance across similar tasks in adversarial bandits.
New algorithm reduces prediction errors across various loss functions.
New bounds for online portfolio selection without smoothness assumptions.
New algorithm tackles heterogeneous curvature in online convex optimization.
The Riemannian Langevin Algorithm samples from manifolds efficiently.
We propose a new proximal, path-following framework for a class of constrained convex problems. We consider settings where the nonlinear---and possibly non-smooth---objective part is endowed with a proximity operator, and the constraint set is equipped with a self-concordant barrier. Our approach relies on the followin…
A new sampling method for log-concave distributions with warm starts and barriers.
The self-concordant-like property of a smooth convex function is a new analytical structure that generalizes the self-concordant notion. While a wide variety of important applications feature the self-concordant-like property, this concept has heretofore remained unexploited in convex optimization. To this end, we deve…
Improves statistical learning bounds with self-concordant losses.
We study the smooth structure of convex functions by generalizing a powerful concept so-called self-concordance introduced by Nesterov and Nemirovskii in the early 1990s to a broader class of convex functions, which we call generalized self-concordant functions. This notion allows us to develop a unified framework for …
Improved Frank-Wolfe algorithm for generalized self-concordant functions converges quickly.
New insights into natural exponential families improve regret bounds for bandit problems.
New method solves constrained self-concordant minimization problems efficiently.
New bounds on minimax regret for sequential probability assignment using logarithmic loss.
We propose a variable metric framework for minimizing the sum of a self-concordant function and a possibly non-smooth convex function, endowed with an easily computable proximal operator. We theoretically establish the convergence of our framework without relying on the usual Lipschitz gradient assumption on the smooth…
Paper improves learning rates for GSC loss functions using iterated Tikhonov regularization.
We analyze the problem of sequential probability assignment for binary outcomes with side information and logarithmic loss, where regret---or, redundancy---is measured with respect to a (possibly infinite) class of experts. We provide upper and lower bounds for minimax regret in terms of sequential complexities of the …
Meta-learning improves performance across similar tasks in adversarial bandit settings.
Improved prediction algorithm for 'easy' sequences with reduced regret.
New sampling method improves accuracy for constrained spaces.
The goal of this note is to construct, on many manifolds, non-trivial concordances from the identity to itself. This produces counterexamples to a recent conjecture by Botvinnik.
We consider the class of convex minimization problems, composed of a self-concordant function, such as the metric, a convex data fidelity term and, a regularizing -- possibly non-smooth -- function . This type of problems have recently attracted a great deal of interest, mainly due to th…
The paper improves confidence set construction for statistical inference.
The classical asymptotic theory for parametric -estimators guarantees that, in the limit of infinite sample size, the excess risk has a chi-square type distribution, even in the misspecified case. We demonstrate how self-concordance of the loss allows to characterize the critical sample size sufficient to guarantee …
Unified CS for GLMs improves bandit regret bounds.
The paper calculates prices for multi-step barrier options under the Black-Scholes model.
We consider distributed convex optimization problems originated from sample average approximation of stochastic optimization, or empirical risk minimization in machine learning. We assume that each machine in the distributed computing system has access to a local empirical loss function, constructed with i.i.d. data sa…
We demonstrate effectiveness of the first-order algorithm from [Milstein, Tretyakov. Theory Prob. Appl. 47 (2002), 53-68] in application to barrier option pricing. The algorithm uses the weak Euler approximation far from barriers and a special construction motivated by linear interpolation of the price near barriers. I…
A new method uses deep learning to price barrier options.
We determine the price of digital double barrier options with an arbitrary number of barrier periods in the Black-Scholes model. This means that the barriers are active during some time intervals, but are switched off in between. As an application, we calculate the value of a structure floor for structured notes whose …
A time-dependent double-barrier option is a derivative security that delivers the terminal value at expiry if neither of the continuous time-dependent barriers $b_\pm:[0,T]\to \RR_+$ have been hit during the time interval . Using a probabilistic approach we obtain a decomposition of the barrier opti…
We discuss the pricing methodology for Bonus Certificates and Barrier Reverse-Convertible Structured Products. Pricing for a European barrier condition is straightforward for products of both types and depends on an efficient interpolation of observed market option pricing. Pricing products We discuss the pricing metho…
Efficient semi-analytic methods for pricing double barrier options with time-dependent parameters.
We provided an analytical representation of the price of a barrier option with one type of special moving barrier. We consider the case that risk free rate, dividend rate and stock volatility are time dependent. We get a pricing formula and put call parity for barrier option when the moving barrier has a special relati…
In this paper we consider the composite self-concordant (CSC) minimization problem, which minimizes the sum of a self-concordant function and a (possibly nonsmooth) proper closed convex function . The CSC minimization is the cornerstone of the path-following interior point methods for solving a broad class of co…
Improved confidence bounds for linear logistic model with applications to bandits.
Hamiltonian method applied to floating barrier options pricing.
We compute the effect of concordance surgery, a generalization of knot surgery defined using a self-concordance of a knot, on the Ozsváth-Szabó 4-manifold invariant. The formula involves the graded Lefschetz number of the concordance map on knot Floer homology. The proof uses the sutured Floer TQFT, and a version of su…