/// <summary>
/// Constructor.
/// </summary>
/// <param name="solver">The root class.</param>
public TspSolver(DvrpSolver solver)
{
_distances = solver._distances;
_depotDistances = solver._depotDistances;
_dvrpProblem = solver._dvrpProblem;
_visited = new bool[_dvrpProblem.Requests.Length];
}
/// <summary>
/// Divide the problem into partial problems.
/// </summary>
/// <param name="dvrpProblem">The problem instance to divide.</param>
/// <param name="numberOfParts">How many parts to divide into.</param>
/// <returns>Output partial problems.</returns>
public DvrpPartialProblem[] Divide(DvrpProblem dvrpProblem, int numberOfParts)
{
// we generate all the partitions
// set {{0 0 0 0 0}} represents {{0 1 2 3 4}}
// set {{0 1 2 3 4}} represents {{0}{1}{2}{3}{4}}
// set {{0 1 2 1 2}} represents {{0}{1 3}{2 4}}
// part - current partition
// max[i] = Max{max[i-1], part[i-1]}
// max[0] = -1
// example:
// 0 0 0
// 0 0 1
// 0 1 0
// 0 1 1
// 0 1 2
if (numberOfParts < 1)
throw new ArgumentOutOfRangeException("numberOfParts");
var n = dvrpProblem.Requests.Length;
var part = new int[n];
var max = new int[n];
var maxNumberofSets = TriangularMethodBellNumber(n);
var numberOfSetsForThread = maxNumberofSets/(ulong) numberOfParts;
var result = new DvrpPartialProblem[numberOfParts];
var solver = new DvrpSolver(dvrpProblem);
var approximateResult = solver.SolveApproximately();
for (var i = n - 2; i > -1; --i)
part[i] = 0;
part[n - 1] = max[0] = -1;
var partLast = (int[]) part.Clone();
ulong j = 0;
var k = 0;
do
{
// checking if max[i] == Max{max[i-1], part[i-1]}
for (var i = 1; i < n; ++i)
{
if (max[i - 1] < part[i - 1])
max[i] = part[i - 1];
else
max[i] = max[i - 1];
}
// we check if the last elements of the set are in their current maximum
// for example
// 01200345 p = 7
// 01200340 p = 6
// 01200300 p = 5
// 01200000 p = 4
// and now we can increment element for after following loop
// 01201000
var p = n - 1;
while (part[p] == max[p] + 1)
{
part[p] = 0;
p = p - 1;
}
#region optimalization
// now it is (n^2) insted of (B*n)
if (p <= n - 2 && p > 1 && CheckZeros(part, p, n))
{
var tmp = CalculateCombinations(max[p], p, n);
if (tmp > numberOfSetsForThread - j - 1)
{
part[p] = part[p] + 1;
++j;
}
else
{
part[p] = max[p] + 1;
for (var i = p + 1; i < n; i++)
{
part[i] = part[i - 1] + 1;
}
j += tmp;
}
}
else if (p == n - 1 && part[p] == 0)
{
var tmp = (int) Math.Min(numberOfSetsForThread - j, (double) max[p] + 1);
part[p] = tmp;
j += (ulong) part[p];
}
else
{
part[p] = part[p] + 1;
++j;
}
#endregion
if (j == numberOfSetsForThread)
{
result[k] = new DvrpPartialProblem(partLast, approximateResult, j, part);
partLast = (int[]) part.Clone();
++k;
j = 0;
if (k == numberOfParts - 1)
{
break;
}
}
// ReSharper disable once LoopVariableIsNeverChangedInsideLoop
} while (part[n - 1] != n - 1);
for (var i = 0; i < n; i++)
{
part[i] = i;
}
result[k] = new DvrpPartialProblem(partLast, approximateResult,
maxNumberofSets - (ulong) k*numberOfSetsForThread, part);
return result;
}
/// <summary>
/// Divide the problem into partial problems.
/// </summary>
/// <param name="dvrpProblem">The problem instance to divide.</param>
/// <param name="numberOfParts">How many parts to divide into.</param>
/// <returns>Output partial problems.</returns>
public DvrpPartialProblem[] Divide(DvrpProblem dvrpProblem, int numberOfParts)
{
// we generate all the partitions
// set {{0 0 0 0 0}} represents {{0 1 2 3 4}}
// set {{0 1 2 3 4}} represents {{0}{1}{2}{3}{4}}
// set {{0 1 2 1 2}} represents {{0}{1 3}{2 4}}
// part - current partition
// max[i] = Max{max[i-1], part[i-1]}
// max[0] = -1
// example:
// 0 0 0
// 0 0 1
// 0 1 0
// 0 1 1
// 0 1 2
if (numberOfParts < 1)
{
throw new ArgumentOutOfRangeException("numberOfParts");
}
var n = dvrpProblem.Requests.Length;
var part = new int[n];
var max = new int[n];
var maxNumberofSets = TriangularMethodBellNumber(n);
var numberOfSetsForThread = maxNumberofSets / (ulong)numberOfParts;
var result = new DvrpPartialProblem[numberOfParts];
var solver = new DvrpSolver(dvrpProblem);
var approximateResult = solver.SolveApproximately();
for (var i = n - 2; i > -1; --i)
{
part[i] = 0;
}
part[n - 1] = max[0] = -1;
var partLast = (int[])part.Clone();
ulong j = 0;
var k = 0;
do
{
// checking if max[i] == Max{max[i-1], part[i-1]}
for (var i = 1; i < n; ++i)
{
if (max[i - 1] < part[i - 1])
{
max[i] = part[i - 1];
}
else
{
max[i] = max[i - 1];
}
}
// we check if the last elements of the set are in their current maximum
// for example
// 01200345 p = 7
// 01200340 p = 6
// 01200300 p = 5
// 01200000 p = 4
// and now we can increment element for after following loop
// 01201000
var p = n - 1;
while (part[p] == max[p] + 1)
{
part[p] = 0;
p = p - 1;
}
#region optimalization
// now it is (n^2) insted of (B*n)
if (p <= n - 2 && p > 1 && CheckZeros(part, p, n))
{
var tmp = CalculateCombinations(max[p], p, n);
if (tmp > numberOfSetsForThread - j - 1)
{
part[p] = part[p] + 1;
++j;
}
else
{
part[p] = max[p] + 1;
for (var i = p + 1; i < n; i++)
{
part[i] = part[i - 1] + 1;
}
j += tmp;
}
}
else if (p == n - 1 && part[p] == 0)
{
var tmp = (int)Math.Min(numberOfSetsForThread - j, (double)max[p] + 1);
part[p] = tmp;
j += (ulong)part[p];
}
else
{
part[p] = part[p] + 1;
++j;
}
#endregion
if (j == numberOfSetsForThread)
{
result[k] = new DvrpPartialProblem(partLast, approximateResult, j, part);
partLast = (int[])part.Clone();
++k;
j = 0;
if (k == numberOfParts - 1)
{
break;
}
}
// ReSharper disable once LoopVariableIsNeverChangedInsideLoop
} while (part[n - 1] != n - 1);
for (var i = 0; i < n; i++)
{
part[i] = i;
}
result[k] = new DvrpPartialProblem(partLast, approximateResult,
maxNumberofSets - (ulong)k * numberOfSetsForThread, part);
return(result);
}
/// <summary>
/// Solve a partial problem with a given timeout.
/// </summary>
/// <param name="partialData">Binary serialized DVRP partial problem data.</param>
/// <param name="timeout">Maximum time for computations.</param>
/// <returns>Binary serialized solution.</returns>
public override byte[] Solve(byte[] partialData, TimeSpan timeout)
{
try
{
DvrpPartialProblem problem;
using (var memoryStream = new MemoryStream(partialData))
{
problem = (DvrpPartialProblem) _formatter.Deserialize(memoryStream);
}
var solver = new DvrpSolver(_dvrpProblem);
using (var memoryStream = new MemoryStream())
{
_formatter.Serialize(memoryStream, solver.Solve(problem, timeout));
State = solver.State;
return memoryStream.ToArray();
}
}
catch (Exception ex)
{
Exception = ex;
State = TaskSolverState.Error;
return null;
}
}
/// <summary>
/// Constructor.
/// </summary>
/// <param name="solver">The root class.</param>
public TspSolver(DvrpSolver solver)
{
_distances = solver._distances;
_depotDistances = solver._depotDistances;
_dvrpProblem = solver._dvrpProblem;
_visited = new bool[_dvrpProblem.Requests.Length];
}