1 citations · 1 across the 15 of their papers we have counts for
17 papers
Race, Exchange, Improve: Finding high-quality MIP solutions quickly
Gioni Mexi, Daniel Rehfeldt
Mixed-integer programming (MIP) is a cornerstone in applied optimization, both in industry and academia. Recently, there has been increased attention to finding strong primal solut…
A Numerically-safe Branch-Price-and-Cut Algorithm for the Length-Constrained Cycle Partition Problem
Mohammed Ghannam, Ambros Gleixner, Gioni Mexi +1
The length-constrained cycle partition problem (LCCP) is a graph optimization problem in which a set of nodes must be partitioned into a minimum number of cycles. Every node is ass…
CHAP: A Hybrid GPU-CPU Heuristic for MIP
Gennesaret Kharistio Tjusila, Alexander Hoen, Nils-Christian Kempke +5
We present CHAP (Coordinating Heuristics Across Platforms) a GPU-CPU-hybrid primal heuristic framework for mixed-integer programming. CHAP adopts a portfolio approach where it coor…
Out-of-the-Box Global Optimization for Packing Problems: New Models and Improved Solutions
Timo Berthold, Dominik Kamp, Gioni Mexi +2
Recent LLM-driven discoveries have renewed interest in geometric packing problems. In this paper, we study several classes of such packing problems through the lens of modern globa…
Global Optimization for Combinatorial Geometry Problems Revisited in the Era of LLMs
Timo Berthold, Dominik Kamp, Gioni Mexi +2
Recent progress in LLM-driven algorithm discovery, exemplified by DeepMind's AlphaEvolve, has produced new best-known solutions for a range of hard geometric and combinatorial prob…
Objective Coefficient Rounding and Almost Symmetries in Binary Programs
Dominik Kuzinowicz, Paweł Lichocki, Gioni Mexi +3
This article investigates the interplay of rounding objective coefficients in binary programs and almost symmetries. Empirically, reducing the number of significant bits through ro…
The SCIP Optimization Suite 10.0
Christopher Hojny, Mathieu Besançon, Ksenia Bestuzheva +31
The SCIP Optimization Suite provides a collection of software packages for mathematical optimization, centered around the constraint integer programming (CIP) framework SCIP. This…
A Frank-Wolfe-based primal heuristic for quadratic mixed-integer optimization
Gioni Mexi, Deborah Hendrych, Sébastien Designolle +2
We propose a primal heuristic for quadratic mixed-integer problems. Our method extends the Boscia framework -- originally a mixed-integer convex solver leveraging a Frank-Wolfe-bas…
Sparsity-driven Aggregation of Mixed Integer Programs
Liding Xu, Gioni Mexi, Ksenia Bestuzheva
Cutting planes are crucial for the performance of branch-and-cut algorithms for solving mixed-integer programming (MIP) problems, and linear row aggregation has been successfully a…
State-of-the-art Methods for Pseudo-Boolean Solving with SCIP
Gioni Mexi, Dominik Kamp, Yuji Shinano +8
The Pseudo-Boolean problem deals with linear or polynomial constraints with integer coefficients over Boolean variables. The objective lies in optimizing a linear objective functio…
Cut-based Conflict Analysis in Mixed Integer Programming
Gioni Mexi, Felipe Serrano, Timo Berthold +2
For almost two decades, mixed integer programming (MIP) solvers have used graph-based conflict analysis to learn from local infeasibilities during branch-and-bound search. In this…
A Multi-Reference Relaxation Enforced Neighborhood Search Heuristic in SCIP
Suresh Bolusani, Gioni Mexi, Mathieu Besançon +1
This paper proposes and evaluates a Multi-Reference Relaxation Enforced Neighborhood Search (MRENS) heuristic within the SCIP solver. This study marks the first integration and eva…
Branch and Price for the Length-Constrained Cycle Partition Problem
Mohammed Ghannam, Gioni Mexi, Edward Lam +1
The length-constrained cycle partition problem (LCCP) is a graph optimization problem in which a set of nodes must be partitioned into a minimum number of cycles. Every node is ass…
The SCIP Optimization Suite 9.0
Suresh Bolusani, Mathieu Besançon, Ksenia Bestuzheva +28
The SCIP Optimization Suite provides a collection of software packages for mathematical optimization, centered around the constraint integer programming (CIP) framework SCIP. This…
Probabilistic Lookahead Strong Branching via a Stochastic Abstract Branching Model
Gioni Mexi, Somayeh Shamsi, Mathieu Besançon +1
Strong Branching (SB) is a cornerstone of all modern branching rules used in the Branch-and-Bound (BnB) algorithm, which is at the center of Mixed-Integer Programming solvers. In i…
Improving Conflict Analysis in MIP Solvers by Pseudo-Boolean Reasoning
Gioni Mexi, Timo Berthold, Ambros Gleixner +1
Conflict analysis has been successfully generalized from Boolean satisfiability (SAT) solving to mixed integer programming (MIP) solvers, but although MIP solvers operate with gene…
Scylla: a matrix-free fix-propagate-and-project heuristic for mixed-integer optimization
Gioni Mexi, Mathieu Besançon, Suresh Bolusani +3
We introduce Scylla, a primal heuristic for mixed-integer optimization problems. It exploits approximate solves of the Linear Programming relaxations through the matrix-free Primal…