public static (Status status, FirstSimplexResult result) Solve(double[,] conditions, double[] constraints)
{
// ReSharper disable InconsistentNaming
var A = LinearAlgebraUtils.BuildMatrixFrom2DArray(conditions);
var b = LinearAlgebraUtils.BuildVectorFromArray(constraints);
// if i-th b's element less than zero, multiply it and i-th A's row by -1
Core.MultiplyByMinusOne(ref A, ref b);
// form initial data for auxiliary problem solving
var(
initialConditions,
initialObjectiveFunction,
initialSolution,
initialBasisIndices) =
InitialValuesUtils.GetInitialValues(A, b);
var mainPhase = new SimplexMainPhaseService(
initialConditions.ToArray(),
initialObjectiveFunction.ToArray(),
initialSolution.ToArray(),
initialBasisIndices);
var result = mainPhase.Maximize();
Debug.WriteLine($"{nameof(result.Solution)}:\n{string.Join(", ", result.Solution)}\n");
Debug.WriteLine($"{nameof(result.BasisIndices)}:\n{string.Join(", ", result.BasisIndices)}\n");
if (!result.HasSolutionChanged(initialSolution)) // lib-specific comparison to determine whether solving has failed
{
return(Status.Fail, FirstSimplexResult.Empty);
}
if (!result.IsCompatible(A.RowCount))
{
return(Status.Incompatible, FirstSimplexResult.Empty);
}
var correctedIndices = Core.GetCorrectedBasisIndices(result, A.ColumnCount, A.RowCount, initialConditions);
return(Status.Success, FirstSimplexResult.Create(result.Solution.Take(A.ColumnCount), correctedIndices));
}
public static Matrix <double> GetBasisMatrix(Matrix <double> source, IEnumerable <int> basisIndices)
{
var columns = basisIndices.Select(source.Column);
return(LinearAlgebraUtils.CreateMatrixFromColumns(columns));
}
