public ShiftMutationAlphaBeta(int maxShift, Random randomGenerator)
{
MaxShift = maxShift;
RandomGenerator = randomGenerator;
_mutationBeta = new ShiftMutationBeta(RandomGenerator, MaxShift);
_mutationAlpha = new ShiftMutationAlpha {
RandomGenerator = RandomGenerator, MaxShift = MaxShift
};
}
public CombinedMutation(Random randomGenerator)
{
RandomGenerator = randomGenerator;
_randomMutation = new RandomMutation {
RandomGenerator = RandomGenerator
};
_shiftMutation = new ShiftMutationAlpha {
RandomGenerator = RandomGenerator, MaxShift = MaxShift
};
}
public ShiftMutationBeta(Random random, int maxShift)
{
MaxShift = maxShift;
RandomGenerator = random;
_mutationAlpha = new ShiftMutationAlpha
{
RandomGenerator = random,
MaxShift = MaxShift
};
}
public void Mutation(Solution solution, ISolutionInitializer initializer)
{
// select random segment
var path = solution.Paths[RandomGenerator.Next(solution.Paths.Length)];
var index = RandomGenerator.Next(path.Segments.Count);
var segment = path.Segments[index];
// random draw new segment length
var len = RandomGenerator.Next(1, segment.Length);
// calculate offset
var offset = RandomGenerator.Next(0, (segment.Length - len) + 1);
// split selected segment
var(sx, sy) = segment.StartPoint;
var(dx, dy) = segment.Direction.CoefficientTuple();
var start = new Point(sx + dx * offset, sy + dy * offset);
var end = new Point(start.X + len * dx, start.Y + len * dy);
var pointsQuery = new[] { segment.StartPoint, segment.EndPoint, start, end }.Distinct();
Point[] points;
if (segment.Direction.GeneralDirection() == Direction.Vertical)
{
points = segment.Direction == Direction.Up
? pointsQuery.OrderByDescending(p => p.Y).ToArray()
: pointsQuery.OrderBy(p => p.Y).ToArray();
}
else
{
points = segment.Direction == Direction.Left
? pointsQuery.OrderByDescending(p => p.X).ToArray()
: pointsQuery.OrderBy(p => p.X).ToArray();
}
// create new tmp solution with start and end in selected segment
var splitSegments = new List <Segment>();
Segment modifiedSegment = null;
var modifiedIndex = 0;
for (var i = 0; i < points.Length - 1; i++)
{
var tmp = new Segment(points[i], segment.Direction,
(int)Point.Distance(points[i], points[i + 1]));
if (tmp.StartPoint == start)
{
modifiedSegment = tmp;
modifiedIndex = i;
}
splitSegments.Add(tmp);
}
// apply shiftMutationAlpha to tmp solution
var tmpPath = new Path(start, end);
tmpPath.Segments.Add(modifiedSegment?.Clone());
var tmpSol = new Solution(solution.Problem, new Path[] { tmpPath });
_mutationAlpha.Mutation(tmpSol, initializer);
// append path of tmp solution
splitSegments.InsertRange(modifiedIndex, tmpPath.Segments);
splitSegments.RemoveAt(modifiedIndex + tmpPath.Segments.Count);
path.Segments.InsertRange(index, splitSegments);
path.Segments.RemoveAt(index + splitSegments.Count);
// fix overlapping neighbors
// previous
if (index - 1 > 0)
{
var prev = path.Segments[index - 1];
if (prev.Direction.OppositeDirection() == path.Segments[index].Direction)
{
var tmpLen = prev.Length - path.Segments[index].Length;
switch (tmpLen)
{
case > 0:
prev.Length = tmpLen;
path.Segments.RemoveAt(index);
--index;
break;
case 0:
path.Segments.RemoveAt(index - 1);
path.Segments.RemoveAt(index - 1);
index -= 2;
break;
default:
prev.Length = -tmpLen;
prev.Direction = prev.Direction.OppositeDirection();
path.Segments.RemoveAt(index);
--index;
break;
}
}
}
// next
if (index + splitSegments.Count < path.Segments.Count)
{
var testedIndex = index + splitSegments.Count - 1;
var next = path.Segments[index + splitSegments.Count];
if (next.Direction.OppositeDirection() == path.Segments[testedIndex].Direction)
{
var tmpLen = next.Length - path.Segments[testedIndex].Length;
switch (tmpLen)
{
case > 0:
next.Length = tmpLen;
next.StartPoint = path.Segments[testedIndex].StartPoint;
path.Segments.RemoveAt(testedIndex);
break;
case 0:
path.Segments.RemoveAt(testedIndex);
path.Segments.RemoveAt(testedIndex);
break;
default:
next.Length = -tmpLen;
next.Direction = next.Direction.OppositeDirection();
next.StartPoint = path.Segments[testedIndex].StartPoint;
path.Segments.RemoveAt(testedIndex);
break;
}
}
}
// repair the path
ShiftMutationAlpha.RepairPath(path);
}