public void TestAngleAbsDifference()
{
const double eps = 1e-10;
Assert.AreEqual(0, MathHelper.AngleAbsDifference(0, 0), eps);
Assert.AreEqual(0, MathHelper.AngleAbsDifference(Math.PI, -Math.PI), eps);
Assert.AreEqual(Math.PI * 0.5, MathHelper.AngleAbsDifference(Math.PI * 0.75, Math.PI * 0.25), eps);
Assert.AreEqual(Math.PI * 0.5, MathHelper.AngleAbsDifference(-Math.PI * 0.75, -Math.PI * 0.25), eps);
Assert.AreEqual(Math.PI * 0.5, MathHelper.AngleAbsDifference(Math.PI * 0.75, -Math.PI * 0.75), eps);
Assert.AreEqual(Math.PI * 0.5, MathHelper.AngleAbsDifference(-Math.PI * 0.75, Math.PI * 0.75), eps);
}
public double CalculateEdgePairAngleEnergyTerm(int edgeIndex1, int edgeIndex2, Vector edge1Vector, Vector edge2Vector)
{
Tuple <int, int> pair = new Tuple <int, int>(edgeIndex1, edgeIndex2);
ShapeEdgePairParams pairParams;
if (!this.edgePairParams.TryGetValue(pair, out pairParams))
{
throw new ArgumentException("Given edge pair has no common pairwise constraints.");
}
double angle = Vector.AngleBetween(edge1Vector, edge2Vector);
double angleDiff = MathHelper.AngleAbsDifference(angle, pairParams.MeanAngle);
double angleTerm = angleDiff * angleDiff / (2 * pairParams.AngleDeviation * pairParams.AngleDeviation);
return(angleTerm);
}
public static ShapeModel Learn(IEnumerable <Shape> shapes, IEnumerable <Tuple <int, int> > constrainedEdgePairs)
{
if (shapes == null)
{
throw new ArgumentNullException("shapes");
}
if (constrainedEdgePairs == null)
{
throw new ArgumentNullException("constrainedEdgePairs");
}
int shapeCount = shapes.Count();
if (shapeCount <= 1)
{
throw new ArgumentException("Can't learn from less than two shapes.", "shapes");
}
ShapeStructure structure = shapes.First().Structure;
if (!shapes.All(s => s.Structure == structure))
{
throw new ArgumentException("All the shapes should have the same structure.", "shapes");
}
// Learn root edge
double rootEdgeLengthDeviation = Double.PositiveInfinity;
double rootEdgeMeanLength = 0;
int rootEdgeIndex = -1;
for (int i = 0; i < structure.Edges.Count; ++i)
{
double lengthSum = 0, lengthSumSqr = 0;
foreach (Shape shape in shapes)
{
double edgeLength = shape.GetEdgeVector(i).Length;
lengthSum += edgeLength;
lengthSumSqr += edgeLength * edgeLength;
}
double meanLength = lengthSumSqr / lengthSum;
double lengthRatioDiffSqrSum = 0;
foreach (Shape shape in shapes)
{
double edgeLength = shape.GetEdgeVector(i).Length;
double lengthRatioDiff = edgeLength / meanLength - 1;
lengthRatioDiffSqrSum += lengthRatioDiff * lengthRatioDiff;
}
double lengthDeviation = Math.Sqrt(lengthRatioDiffSqrSum / shapeCount);
if (rootEdgeIndex == -1 || lengthDeviation < rootEdgeLengthDeviation)
{
rootEdgeLengthDeviation = lengthDeviation;
rootEdgeMeanLength = meanLength;
rootEdgeIndex = i;
}
}
// Learn edge params
List <ShapeEdgeParams> shapeEdgeParams = new List <ShapeEdgeParams>();
for (int i = 0; i < structure.Edges.Count; ++i)
{
double sum = 0, sumSqr = 0;
foreach (Shape shape in shapes)
{
double edgeLength = shape.GetEdgeVector(i).Length;
double ratio = shape.EdgeWidths[i] / edgeLength;
sum += ratio;
sumSqr += ratio * ratio;
}
double meanWidthToLengthRatio = sum / shapeCount;
double widthToLengthRatioDeviation = Math.Sqrt(sumSqr / shapeCount - meanWidthToLengthRatio * meanWidthToLengthRatio);
shapeEdgeParams.Add(new ShapeEdgeParams(meanWidthToLengthRatio, widthToLengthRatioDeviation));
}
// Learn edge pair params
Dictionary <Tuple <int, int>, ShapeEdgePairParams> shapeEdgePairParams =
new Dictionary <Tuple <int, int>, ShapeEdgePairParams>();
foreach (Tuple <int, int> edgePair in constrainedEdgePairs)
{
if (edgePair.Item1 < 0 || edgePair.Item1 >= structure.Edges.Count || edgePair.Item2 < 0 || edgePair.Item2 >= structure.Edges.Count)
{
throw new ArgumentOutOfRangeException("constrainedEdgePairs", "Set of constrained edge pairs contains invalid edge index.");
}
ShapeEdge edge1 = structure.Edges[edgePair.Item1];
ShapeEdge edge2 = structure.Edges[edgePair.Item2];
if (edge1.Index1 != edge2.Index1 && edge1.Index2 != edge2.Index1 &&
edge1.Index1 != edge2.Index2 && edge1.Index2 != edge2.Index2)
{
throw new ArgumentException("Constrained edge pairs should be connected.", "constrainedEdgePairs");
}
// Learn means
double lengthProdSum = 0, lengthSqrSum = 0;
double meanAngle = 0;
int shapesConsidered = 0;
foreach (Shape shape in shapes)
{
++shapesConsidered;
Vector edge1Vec = shape.GetEdgeVector(edgePair.Item1);
Vector edge2Vec = shape.GetEdgeVector(edgePair.Item2);
double length1 = edge1Vec.Length;
double length2 = edge2Vec.Length;
lengthProdSum += length1 * length2;
lengthSqrSum += length2 * length2;
double angle = Vector.AngleBetween(edge1Vec, edge2Vec);
meanAngle = MathHelper.InterpolateAngle(meanAngle, angle, 1.0 / shapesConsidered);
}
double meanLengthRatio = lengthProdSum / lengthSqrSum;
// Learn deviations
double angleAbsDiffSqrSum = 0;
double lengthDiffSqrSum = 0;
foreach (Shape shape in shapes)
{
Vector edge1Vec = shape.GetEdgeVector(edgePair.Item1);
Vector edge2Vec = shape.GetEdgeVector(edgePair.Item2);
double length1 = edge1Vec.Length;
double length2 = edge2Vec.Length;
double lengthDiff = length1 - meanLengthRatio * length2;
lengthDiffSqrSum += lengthDiff * lengthDiff;
double angle = Vector.AngleBetween(edge1Vec, edge2Vec);
double angleDiff = MathHelper.AngleAbsDifference(meanAngle, angle);
angleAbsDiffSqrSum += angleDiff * angleDiff;
}
double lengthDiffDeviation = Math.Sqrt(lengthDiffSqrSum / shapeCount);
double angleDeviation = Math.Sqrt(angleAbsDiffSqrSum / shapeCount);
if (shapeEdgePairParams.ContainsKey(edgePair) || shapeEdgePairParams.ContainsKey(new Tuple <int, int>(edgePair.Item2, edgePair.Item1)))
{
throw new ArgumentException("Same pair of edges is constrained more than once.", "constrainedEdgePairs");
}
shapeEdgePairParams.Add(edgePair, new ShapeEdgePairParams(meanAngle, meanLengthRatio, angleDeviation, lengthDiffDeviation));
}
return(new ShapeModel(structure, shapeEdgeParams, shapeEdgePairParams, rootEdgeIndex, rootEdgeMeanLength, rootEdgeLengthDeviation));
}
