We present a neural network approach to solve exact and inexact graph isomorphism problems for weighted graphs. In contrast to other neural heuristics or related methods this approach is based on a neural refinement procedure to reduce the search space followed by an energy-minimizing matching process. Experiments on random weighted graphs in the range of 100–5000 vertices and on chemical molec...

We propose a family of search directions based on primal-dual entropy in the contextof interior-point methods for linear optimization. We show that by using entropy based searchdirections in the predictor step of a predictor-corrector algorithm together with a homogeneousself-dual embedding, we can achieve the current best iteration complexity bound for linear opti-mization. The...

We propose a family of search directions based on primal-dual entropy in the context of interior point methods for linear programming. This new family contains previously proposed search directions in the context of primal-dual entropy. We analyze the new family of search directions by studying their primal-dual affine-scaling and constant-gap centering components. We then design primal-dual in...

We discuss which are the main research themes in the field of search results clustering and report some recent results achieved by the Information Mining group at Fondazione Ugo Bordoni.

Inexact Krylov subspace methods have been shown to be practical alternatives for the solution of certain linear systems of equations. In this paper, the solution of singular systems with inexact matrix-vector products is explored. Criteria are developed to prescribe how inexact the matrix-vector products can be, so that the computed residual remains close to the true residual, thus making the i...

-----------------------------The efficient combination of directions is a significant problem in line search methods that either use negative curvature. or wish to include additional information such as the gradient or different approximations to the Newton direction. In thls paper we describe a new procedure to combine several of these directions within an interior-point primal-dual algorithm....

Two nonsymmetric search directions for semideenite programming, the XZ and ZX search directions, are proposed. They are derived from a nonsymmetric formulation of the semideenite programming problem. The XZ direction corresponds to the direct linearization of the central path equation XZ = I; while the ZX direction corresponds to ZX = I. The XZ and ZX directions are well deened if both X and Z ...

Using modular arithmetic we introduce a simple bound which applies to a wide range of bin-packing like problems. This bound must hold if a problem is to be soluble. When it fails, search can therefore be pruned. We show the value of such pruning in a greedy backtracking algorithm for number partitioning problems. As the bound can be used when solving inexact as well as exact partitioning proble...

Existing distributed hash tables provide efficient mechanisms for storing and retrieving a data item based on an exact key, but are unsuitable when the search key is similar, but not identical, to the key used to store the data item. In this paper, we present a scalable and efficient peerto-peer system with a new search primitive that can efficiently find the k data items with keys closest to t...