What this method is
Aggregate inventory formulation is an exact solver-backed ULS strategy. It builds a mathematical formulation and delegates the optimization step to the selected external engine while keeping the common IUlsSolver result contract.
Core idea
The method builds its portable linear or mixed-integer formulation, automatically selects an available engine in the CPLEX -> Gurobi -> Xpress -> CBC priority order, solves the model, normalizes numerical values and reconstructs a UlsSolution that is checked independently.
Aggregate inventory-balance model
The equations below use periods 1,...,T for readability. The C# API uses zero-based indices 0,...,T-1.
x_t productiony_t setupI_t end-of-period inventorysubject to
ULSAlgorithms uses the tight suffix-demand bound D[t..T] rather than an arbitrary big-M.
Minimal C# example
using ULSAlgorithms.Abstractions;
using ULSAlgorithms.Models;
using ULSAlgorithms.Exact.Formulations;
var problem = new UlsProblem(
demands: [20.0, 30.0, 25.0, 40.0],
setupCosts: [200.0, 200.0, 200.0, 200.0],
unitProductionCosts: [0.0, 0.0, 0.0, 0.0],
holdingCosts: [4.0, 4.0, 4.0, 0.0]);
IUlsSolver solver = new AggregateInventoryFormulationSolver();
var result = solver.Solve(problem);
Console.WriteLine(result.Status);
Console.WriteLine(result.ObjectiveValue);The input example intentionally uses stationary, positive-demand data so it is compatible with restricted methods too. Always check the applicability box for your own instance.