/// <summary>
/// Sweeps between the <paramref name="startLayerIndex"/> and <paramref name="endLayerIndex"/>
/// in the way represented by the step
/// </summary>
/// <param name="startLayerIndex">The index of the start layer (where the sweeping starts from).</param>
/// <param name="endLayerIndex">The index of the last layer (where the sweeping ends).</param>
/// <param name="step">Increment or decrement of the layer index. (1 or -1)</param>
/// <returns>The number of the edge crossings.</returns>
private int Sweeping(int startLayerIndex, int endLayerIndex, int step, bool enableSameMeasureOptimization, out bool changed, ref int phase)
{
int crossings = 0;
changed = false;
if (_alternatingLayers.Length > 0)
{
AlternatingLayer alternatingLayer;
if (_alternatingLayers[startLayerIndex] == null)
{
alternatingLayer = new AlternatingLayer();
alternatingLayer.AddRange(_layers[startLayerIndex].OfType <IData>());
alternatingLayer.EnsureAlternatingAndPositions();
AddAlternatingLayerToSparseCompactionGraph(alternatingLayer, startLayerIndex);
_alternatingLayers[startLayerIndex] = alternatingLayer;
}
else
{
alternatingLayer = _alternatingLayers[startLayerIndex];
}
OutputAlternatingLayer(alternatingLayer, startLayerIndex, 0);
for (int i = startLayerIndex; i != endLayerIndex; i += step)
{
int ci = Math.Min(i, i + step);
int prevCrossCount = _crossCounts[ci];
if (_alternatingLayers[i + step] != null)
{
alternatingLayer.SetPositions();
_alternatingLayers[i + step].SetPositions();
prevCrossCount = DoCrossCountingAndOptimization(alternatingLayer, _alternatingLayers[i + step], (i < i + step), false, (phase == 2), int.MaxValue);
_crossCounts[ci] = prevCrossCount;
}
int crossCount = CrossingMinimizationBetweenLayers(ref alternatingLayer, i, i + step, enableSameMeasureOptimization, prevCrossCount, phase);
if (crossCount < prevCrossCount || phase == 2 || changed)
{
/* set the sparse compaction graph */
AddAlternatingLayerToSparseCompactionGraph(alternatingLayer, i + step);
ReplaceLayer(alternatingLayer, i + step);
_alternatingLayers[i + step] = alternatingLayer;
OutputAlternatingLayer(alternatingLayer, i + step, crossCount);
_crossCounts[i] = crossCount;
crossings += crossCount;
changed = true;
}
else
{
Debug.WriteLine("Layer " + (i + step) + " has not changed.");
alternatingLayer = _alternatingLayers[i + step];
crossings += prevCrossCount;
}
}
}
return(crossings);
}
private int CrossingMinimizationBetweenLayers(
[NotNull, ItemNotNull] ref AlternatingLayer alternatingLayer,
int actualLayerIndex,
int nextLayerIndex,
bool enableSameMeasureOptimization,
int prevCrossCount,
int phase)
{
// Decide which way we are sweeping (up or down)
// Straight = down, reverse = up
bool straightSweep = actualLayerIndex < nextLayerIndex;
AlternatingLayer nextAlternatingLayer = alternatingLayer.Clone();
// 1
AppendSegmentsToAlternatingLayer(nextAlternatingLayer, straightSweep);
// 2
ComputeMeasureValues(alternatingLayer, nextLayerIndex, straightSweep);
nextAlternatingLayer.SetPositions();
// 3
nextAlternatingLayer = InitialOrderingOfNextLayer(nextAlternatingLayer, _layers[nextLayerIndex], straightSweep);
// 4
PlaceQVertices(nextAlternatingLayer, _layers[nextLayerIndex], straightSweep);
nextAlternatingLayer.SetPositions();
// 5
int crossCount = DoCrossCountingAndOptimization(
alternatingLayer,
nextAlternatingLayer,
straightSweep,
enableSameMeasureOptimization,
phase == 2,
prevCrossCount);
// 6
nextAlternatingLayer.EnsureAlternatingAndPositions();
alternatingLayer = nextAlternatingLayer;
return(crossCount);
}
/// <summary>
/// Sweeps between the <paramref name="startLayerIndex"/> and <paramref name="endLayerIndex"/>
/// in the way represented by the step.
/// </summary>
/// <param name="startLayerIndex">The index of the start layer (where the sweeping starts from).</param>
/// <param name="endLayerIndex">The index of the last layer (where the sweeping ends).</param>
/// <param name="step">Increment or decrement of the layer index. (1 or -1)</param>
/// <param name="enableSameMeasureOptimization">Indicates if the same measure optimization is enabled.</param>
/// <param name="changed">Indicates if layer has changed or not.</param>
/// <param name="phase">Algorithm phase.</param>
/// <returns>The number of the edge crossings.</returns>
private int Sweeping(
int startLayerIndex,
int endLayerIndex,
int step,
bool enableSameMeasureOptimization,
out bool changed,
ref int phase)
{
int crossings = 0;
changed = false;
AlternatingLayer alternatingLayer;
AlternatingLayer layer = _alternatingLayers[startLayerIndex];
if (layer is null)
{
alternatingLayer = new AlternatingLayer();
alternatingLayer.AddRange(
_layers[startLayerIndex]
#if !SUPPORTS_ENUMERABLE_COVARIANT
.OfType <IData>()
#endif
);
alternatingLayer.EnsureAlternatingAndPositions();
AddAlternatingLayerToSparseCompactionGraph(alternatingLayer, startLayerIndex);
_alternatingLayers[startLayerIndex] = alternatingLayer;
}
else
{
alternatingLayer = layer;
}
for (int i = startLayerIndex; i != endLayerIndex; i += step)
{
int ci = Math.Min(i, i + step);
int prevCrossCount = _crossCounts[ci];
AlternatingLayer nextAlternatingLayer = _alternatingLayers[i + step];
if (nextAlternatingLayer != null)
{
alternatingLayer?.SetPositions();
nextAlternatingLayer.SetPositions();
prevCrossCount = DoCrossCountingAndOptimization(
alternatingLayer,
nextAlternatingLayer,
i < i + step,
false,
phase == 2,
int.MaxValue);
_crossCounts[ci] = prevCrossCount;
}
int crossCount = CrossingMinimizationBetweenLayers(
ref alternatingLayer,
i, i + step,
enableSameMeasureOptimization,
prevCrossCount,
phase);
if (crossCount < prevCrossCount || phase == 2 || changed)
{
// Set the sparse compaction graph
AddAlternatingLayerToSparseCompactionGraph(alternatingLayer, i + step);
ReplaceLayer(alternatingLayer, i + step);
_alternatingLayers[i + step] = alternatingLayer;
_crossCounts[i] = crossCount;
crossings += crossCount;
changed = true;
}
else
{
alternatingLayer = nextAlternatingLayer;
crossings += prevCrossCount;
}
}
return(crossings);
}
