public void SparseAndDenseSolversGiveSameResult()
{
var rng = new Random(42);
const int numberOfRuns = 500;
const int numRows = 400;
const int numCols = 400;
for (var run = 0; run < numberOfRuns; run++)
{
var dense = new double[numRows, numCols];
for (var i = 0; i < numRows; i++)
{
for (var j = 0; j < numCols; j++)
{
dense[i, j] = rng.Next(1, 100);
}
}
var sparse = new SparseMatrixDouble(dense);
var solver = new ShortestPathSolver();
var denseResult = solver.Solve(dense);
var sparseResult = solver.Solve(sparse);
// Check that all assignments agree. In principle, they don't have to if more than
// one optimal solution exists, but this is somewhat unlikely when we're dealing
// with random doubles.
var denseObjective = Enumerable.Range(0, numRows).Sum(i => dense[i, denseResult.ColumnAssignment[i]]);
var sparseObjective = Enumerable.Range(0, numRows).Sum(i => dense[i, sparseResult.ColumnAssignment[i]]);
Assert.Equal(denseObjective, sparseObjective);
}
}
public void SolveThrowsWhenNoFeasibleSolutionExists()
{
var cost = new[, ] {
{ double.PositiveInfinity }
};
var solver = new ShortestPathSolver();
Assert.Throws <InvalidOperationException>(() => solver.Solve(cost));
}
public void LoadMaze(IMaze maze, MazeStats mazeStats)
{
_currentMaze = maze;
_currentStats = mazeStats;
_mazeDistanceInfo = CellDistanceSolver.GetPassableDistancesFromCell(_currentMaze.StartingCell);
_mazeShortestPathInfo = ShortestPathSolver.Solve(_currentMaze.FinishingCell, _mazeDistanceInfo);
UpdateMazeRendering();
ResetMazePositionAndScaling();
}
public void SolveSparseGivesExpectedResult(
double[,] dense,
int[] expectedColumnAssignment,
int[] expectedRowAssignment)
{
var solver = new ShortestPathSolver();
var cost = new SparseMatrixDouble(dense);
var solution = solver.Solve(cost);
Assert.Equal(expectedColumnAssignment, solution.ColumnAssignment);
Assert.Equal(expectedRowAssignment, solution.RowAssignment);
}
public void SolveThrowsForNonTrivialNonSquareInputWithoutFeasibleSolution()
{
var dense = new[, ]
{
{ .2, double.PositiveInfinity, double.PositiveInfinity },
{ .3, double.PositiveInfinity, double.PositiveInfinity }
};
var sparse = new SparseMatrixDouble(dense);
var solver = new ShortestPathSolver();
Assert.Throws <InvalidOperationException>(() => solver.Solve(dense));
Assert.Throws <InvalidOperationException>(() => solver.Solve(sparse));
}
public void SolveGivesExpectedResult(
double[,] cost,
int[] expectedColumnAssignment,
int[] expectedRowAssignment,
double[] expectedDualU,
double[] expectedDualV)
{
var solver = new ShortestPathSolver();
var solution = solver.Solve(cost);
Assert.IsAssignableFrom <AssignmentWithDuals>(solution);
var solutionWithDuals = (AssignmentWithDuals)solution;
Assert.Equal(expectedColumnAssignment, solution.ColumnAssignment);
Assert.Equal(expectedRowAssignment, solution.RowAssignment);
Assert.Equal(expectedDualU, solutionWithDuals.DualU);
Assert.Equal(expectedDualV, solutionWithDuals.DualV);
}
static void Main(string[] args)
{
const string pngFileName = "rendering.png";
var maze = new TriangleMaze(20, 40, WallSetupAlgorithm.RecursiveBackTracker);
var mazeDistanceInfo = CellDistanceSolver.GetPassableDistancesFromCell(maze.StartingCell);
var mazeShortestPathInfo = ShortestPathSolver.Solve(maze.FinishingCell, mazeDistanceInfo);
var renderOptions = new RenderOptions
{
ShowGradientOfDistanceFromStart = true,
HighlightShortestPath = true,
//ShowAllDistances = true,
};
using (var image = maze.RenderWithSkia(renderOptions, mazeDistanceInfo, mazeShortestPathInfo))
using (var data = image.Encode(SKEncodedImageFormat.Png, 100))
using (var stream = File.OpenWrite(pngFileName))
{
data.SaveTo(stream);
}
}
