/// <summary>
/// Obtém o valor da estimativa a ser adicionada a cada um dos nós durante o algoritmo.
/// </summary>
/// <param name="input">Os dados de entrada.</param>
/// <param name="line">A linha correspondente ao nó de cobertura.</param>
/// <param name="component">A matriz dos custos.</param>
/// <returns>O valor da estimativa.</returns>
private ElementType GetBigDelta(
DualHeuristicAlgInput <ElementType> input,
KeyValuePair <int, ILongSparseMatrixLine <ElementType> > line,
SparseDictionaryMathMatrix <ElementType> component)
{
var result = this.ring.Add(input.Gamma, this.ring.AdditiveInverse(input.Taus[line.Key]));
foreach (var otherLine in component.GetLines())
{
if (otherLine.Key != line.Key)
{
if (otherLine.Value.ContainsColumn(line.Key))
{
var currentCost = otherLine.Value[line.Key];
var currentLambda = input.Lambdas[line.Key];
if (this.comparer.Compare(currentLambda, currentCost) >= 0)
{
var difference = this.ring.Add(
input.Gamma,
this.ring.AdditiveInverse(input.Taus[otherLine.Key]));
if (this.comparer.Compare(difference, result) < 0)
{
result = difference;
}
}
}
}
}
return(result);
}
/// <summary>
/// Obtém os valores iniciais das variáveis lambda.
/// </summary>
/// <param name="matrix">A matriz dos custos.</param>
/// <param name="greedySolution">A solução do algoritmo guloso.</param>
/// <param name="dualInput">A entrada para o algoritmo dual propriamente dito.</param>
/// <returns>Verdadeiro caso o algoritmo seja bem sucedido e falso caso contrário.</returns>
public bool Run(
SparseDictionaryMathMatrix <ElementType> matrix,
GreedyAlgSolution <ElementType> greedySolution,
DualHeuristicAlgInput <ElementType> dualInput)
{
if (matrix == null)
{
throw new ArgumentNullException("matrix");
}
else if (greedySolution == null)
{
throw new ArgumentNullException("greedySolution");
}
else if (dualInput == null)
{
throw new ArgumentNullException("dualInput");
}
else
{
dualInput.Lambdas.Clear();
var componentEnum = matrix.GetLines().GetEnumerator();
if (componentEnum.MoveNext())
{
dualInput.Lambdas.Add(componentEnum.Current.Key, this.ring.AdditiveUnity);
foreach (var column in componentEnum.Current.Value.GetColumns())
{
if (column.Key != componentEnum.Current.Key)
{
if (greedySolution.Chosen.Contains(column.Key))
{
dualInput.Lambdas.Add(column.Key, this.ring.AdditiveUnity);
}
else
{
dualInput.Lambdas.Add(column.Key, column.Value);
}
}
}
while (componentEnum.MoveNext())
{
if (greedySolution.Chosen.Contains(componentEnum.Current.Key))
{
foreach (var column in componentEnum.Current.Value.GetColumns())
{
if (column.Key != componentEnum.Current.Key)
{
var forComponentValue = this.ring.AdditiveUnity;
if (dualInput.Lambdas.TryGetValue(column.Key, out forComponentValue))
{
if (this.comparer.Compare(column.Value, forComponentValue) < 0)
{
dualInput.Lambdas[column.Key] = column.Value;
}
}
else
{
dualInput.Lambdas.Add(column.Key, this.ring.AdditiveUnity);
}
}
}
}
}
}
return(true);
}
}
/// <summary>
/// Aplica o algoritmo sobre a matriz dos custos.
/// </summary>
/// <param name="costs">A matriz dos custos.</param>
/// <param name="numberOfMedians">O número de medianas a serem escolhidas.</param>
/// <returns>O resultado da relaxação.</returns>
public CoeffType[] Run(SparseDictionaryMathMatrix <CoeffType> costs, int numberOfMedians)
{
if (costs == null)
{
throw new ArgumentNullException("costs");
}
else
{
var numberOfVertices = costs.GetLength(1);
var objectiveFunction = new List <SimplexMaximumNumberField <CoeffType> >();
// A mediana que cobre todas as outras é ligeiramente diferente
objectiveFunction.Add(new SimplexMaximumNumberField <CoeffType>(
this.coeffsField.AdditiveUnity,
this.coeffsField.AdditiveInverse(this.coeffsField.MultiplicativeUnity)));
for (int i = 1; i < numberOfVertices; ++i)
{
objectiveFunction.Add(new SimplexMaximumNumberField <CoeffType>(
this.coeffsField.AdditiveUnity,
this.coeffsField.AddRepeated(
this.coeffsField.AdditiveInverse(this.coeffsField.MultiplicativeUnity),
2)));
}
// Adiciona as variáveis x à função objectivo.
var numberXVars = 0;
foreach (var line in costs.GetLines())
{
foreach (var column in line.Value.GetColumns())
{
if (line.Key != column.Key)
{
++numberXVars;
var valueToAdd = new SimplexMaximumNumberField <CoeffType>(
column.Value,
this.coeffsField.AdditiveInverse(this.coeffsField.MultiplicativeUnity));
objectiveFunction.Add(valueToAdd);
}
}
}
// Cria a matriz das restrições e preenche-a com os valores correctos
var constraintsNumber = numberXVars + numberOfVertices;
var nonBasicVariables = new int[objectiveFunction.Count];
var basicVariables = new int[constraintsNumber];
var linesLength = nonBasicVariables.Length + basicVariables.Length;
// Preence os vectores que permitem seleccionar as variáveis.
this.FillVariablesSelectors(nonBasicVariables, basicVariables, linesLength);
// Preencimento da matriz das restrições
var constraintsMatrix = new ArrayMathMatrix <CoeffType>(
constraintsNumber,
constraintsNumber,
this.coeffsField.AdditiveUnity);
var constraintLineNumber = 0;
var constraintXYLineNumber = 0;
var unity = this.coeffsField.MultiplicativeUnity;
var inverseAdditive = this.coeffsField.AdditiveInverse(unity);
foreach (var line in costs.GetLines())
{
foreach (var column in line.Value.GetColumns())
{
if (line.Key != column.Key)
{
constraintsMatrix[constraintXYLineNumber, constraintLineNumber] = inverseAdditive;
constraintsMatrix[constraintXYLineNumber, constraintXYLineNumber + numberOfVertices] = unity;
++constraintXYLineNumber;
}
}
++constraintLineNumber;
}
var lastLine = constraintsNumber - 1;
constraintsMatrix[lastLine, 0] = unity;
constraintLineNumber = numberXVars;
for (int i = 1; i < numberOfVertices; ++i)
{
constraintsMatrix[constraintLineNumber, i] = unity;
constraintsMatrix[lastLine, i] = unity;
constraintXYLineNumber = numberOfVertices;
foreach (var lines in costs.GetLines())
{
foreach (var column in lines.Value.GetColumns())
{
if (lines.Key != column.Key)
{
if (column.Key == i)
{
constraintsMatrix[constraintLineNumber, constraintXYLineNumber] = unity;
}
++constraintXYLineNumber;
}
}
}
++constraintLineNumber;
}
// Preenchimento do vector independente das restrições
var vector = new ArrayMathVector <CoeffType>(constraintsNumber, this.coeffsField.AdditiveUnity);
lastLine = constraintsNumber - 1;
for (int i = numberXVars; i < lastLine; ++i)
{
vector[i] = unity;
}
vector[lastLine] = this.conversion.InverseConversion(numberOfMedians);
var sumVector = this.coeffsField.AdditiveUnity;
for (int i = 0; i < vector.Length; ++i)
{
sumVector = this.coeffsField.Add(sumVector, vector[i]);
}
sumVector = this.coeffsField.AdditiveInverse(sumVector);
var simplexInput = new SimplexInput <CoeffType, SimplexMaximumNumberField <CoeffType> >(
basicVariables,
nonBasicVariables,
new ArrayMathVector <SimplexMaximumNumberField <CoeffType> >(objectiveFunction.ToArray()),
new SimplexMaximumNumberField <CoeffType>(this.coeffsField.AdditiveUnity, sumVector),
constraintsMatrix,
vector);
var resultSimplexSol = this.simplexAlg.Run(simplexInput);
var result = new CoeffType[numberOfVertices];
Array.Copy(resultSimplexSol.Solution, result, numberOfVertices);
return(result);
}
}
/// <summary>
/// Realiza as iterações de melhoramento sobre os dados aproximados inicialmente.
/// </summary>
/// <param name="refsNumber">O número de referências.</param>
/// <param name="matrix">A matriz dos custos.</param>
/// <param name="input">Os dados de entrada.</param>
/// <returns>O valor do custo dual.</returns>
private ElementType Process(
int refsNumber,
SparseDictionaryMathMatrix <ElementType> matrix,
DualHeuristicAlgInput <ElementType> input)
{
var multiplicativeSymmetric = this.ring.AdditiveInverse(this.ring.MultiplicativeUnity);
var delta = this.ring.AdditiveUnity;
while (!this.ring.IsMultiplicativeUnity(delta))
{
foreach (var line in matrix.GetLines())
{
var bigDelta = this.GetBigDelta(
input,
line,
matrix);
var currentLambda = input.Lambdas[line.Key];
if (input.Cbar.ContainsKey(line.Key))
{
var value = this.ring.Add(
input.Cbar[line.Key],
this.ring.AdditiveInverse(currentLambda));
if (this.comparer.Compare(value, bigDelta) < 0)
{
bigDelta = value;
delta = this.ring.MultiplicativeUnity;
input.Cbar.Remove(line.Key);
// TODO: cbar = min(u que cobre line tal que o custo é maior que lambda[line]
foreach (var coverLine in matrix.GetLines())
{
if (coverLine.Key != line.Key)
{
if (coverLine.Value.ContainsColumn(line.Key))
{
var currentCost = coverLine.Value[line.Key];
var compareCost = this.ring.Add(currentLambda, bigDelta);
if (this.comparer.Compare(compareCost, currentCost) < 0)
{
var currentCbar = this.ring.AdditiveUnity;
if (input.Cbar.TryGetValue(line.Key, out currentCbar))
{
if (this.comparer.Compare(currentCost, currentCbar) < 0)
{
input.Cbar[line.Key] = currentCost;
}
}
else
{
input.Cbar.Add(line.Key, currentCost);
}
}
}
}
}
}
}
if (this.comparer.Compare(this.ring.AdditiveUnity, bigDelta) < 0)
{
foreach (var coveringLine in matrix.GetLines())
{
if (coveringLine.Key != line.Key)
{
if (coveringLine.Value.ContainsColumn(line.Key))
{
if (this.comparer.Compare(coveringLine.Value[line.Key], currentLambda) <= 0)
{
input.Taus[coveringLine.Key] = this.ring.Add(
input.Taus[coveringLine.Key],
bigDelta);
}
}
}
}
input.Lambdas[line.Key] = this.ring.Add(input.Lambdas[line.Key], bigDelta);
input.Taus[line.Key] = this.ring.Add(input.Taus[line.Key], bigDelta);
}
}
}
var result = this.ring.AdditiveUnity;
var prod = this.ring.AddRepeated(input.Gamma, refsNumber);
foreach (var line in matrix.GetLines())
{
result = this.ring.Add(result, input.Lambdas[line.Key]);
}
result = this.ring.Add(result, this.ring.AdditiveInverse(prod));
return(result);
}
public ElementType Run(
SparseDictionaryMathMatrix <ElementType> matrix,
DualHeuristicAlgInput <ElementType> input)
{
if (matrix == null)
{
throw new ArgumentNullException("matrix");
}
else if (input == null)
{
throw new ArgumentNullException("input");
}
else
{
input.Taus.Clear();
var result = new Dictionary <int, ElementType>();
input.Gamma = this.ring.AdditiveUnity;
var currentGamma = this.ring.AdditiveUnity;
foreach (var line in matrix.GetLines())
{
// Setup the tau and cbar values
var tempTau = input.Lambdas[line.Key];
foreach (var coveredLine in line.Value.GetColumns())
{
if (coveredLine.Key != line.Key)
{
var difference = this.ring.Add(
input.Lambdas[coveredLine.Key],
this.ring.AdditiveInverse(coveredLine.Value));
if (this.comparer.Compare(difference, this.ring.AdditiveUnity) < 0)
{
tempTau = this.ring.Add(tempTau, difference);
}
}
}
if (this.comparer.Compare(input.Gamma, tempTau) < 0)
{
input.Gamma = tempTau;
}
if (this.comparer.Compare(currentGamma, tempTau) < 0)
{
currentGamma = tempTau;
}
input.Taus.Add(line.Key, tempTau);
}
foreach (var line in matrix.GetLines())
{
foreach (var coveredLine in line.Value.GetColumns())
{
if (coveredLine.Key != line.Key)
{
var tempCbarValue = this.ring.Add(
coveredLine.Value,
this.ring.AdditiveInverse(input.Lambdas[coveredLine.Key]));
if (this.comparer.Compare(this.ring.AdditiveUnity, tempCbarValue) < 0)
{
var currentCbarInCoveredVertice = this.ring.AdditiveUnity;
if (input.Cbar.TryGetValue(coveredLine.Key, out currentCbarInCoveredVertice))
{
if (this.comparer.Compare(tempCbarValue, currentCbarInCoveredVertice) < 0)
{
input.Cbar[coveredLine.Key] = coveredLine.Value;
}
}
else
{
input.Cbar.Add(coveredLine.Key, coveredLine.Value);
}
}
}
}
}
return(currentGamma);
}
}
/// <summary>
/// Escolhe a referência que minimiza a perda.
/// </summary>
/// <param name="chosenReferences">As referências escolhidas anteriormente.</param>
/// <param name="currentMatrix">A matriz dos custos.</param>
/// <param name="currentLineBoard">A linha que contém a condensação dos custos das linhas escolhidas.</param>
/// <returns>O índice da linha correspondente à próxima referência bem como a perda respectiva.</returns>
public Tuple <int, ElementType> Run(
IntegerSequence chosenReferences,
SparseDictionaryMathMatrix <ElementType> currentMatrix,
ElementType[] currentLineBoard)
{
var result = -1;
var currentMinimumLost = default(ElementType);
var lines = currentMatrix.GetLines();
if (chosenReferences.Count > 2)
{
currentMinimumLost = this.GetMinimumSum(
chosenReferences,
currentMatrix,
currentLineBoard,
lines,
2);
result = 2;
}
Parallel.For(2, chosenReferences.Count,
chosenSolution =>
{
var sum = this.GetMinimumSum(
chosenReferences,
currentMatrix,
currentLineBoard,
lines,
chosenSolution);
lock (this.lockObject)
{
if (this.comparer.Compare(sum, currentMinimumLost) < 0)
{
currentMinimumLost = sum;
result = chosenSolution;
}
}
});
if (result != -1)
{
var solutionValue = chosenReferences[result];
var minimumCover = this.GetMinimumCover(
chosenReferences,
lines,
solutionValue);
currentLineBoard[solutionValue] = minimumCover;
var columns = currentMatrix.GetColumns(solutionValue);
foreach (var column in columns)
{
if (column.Key != solutionValue)
{
var currentValue = currentMatrix[solutionValue, column.Key];
if (this.ring.Equals(currentValue, currentLineBoard[column.Key]))
{
minimumCover = this.GetMinimumCover(
chosenReferences,
lines,
solutionValue);
currentLineBoard[column.Key] = minimumCover;
}
}
}
}
return(Tuple.Create(result, currentMinimumLost));
}