/// <summary>
///
/// </summary>
/// <param name="other"></param>
public Grid2d(Grid2d other)
{
_dx = other._dx;
_dy = other._dy;
_tx = other._tx;
_ty = other._ty;
_txInv = other._txInv;
_tyInv = other._tyInv;
_nx = other._nx;
_ny = other._ny;
_nxy = other._nxy;
_wrapX = other._wrapX;
_wrapY = other._wrapY;
}
/// <summary>
/// Calculates the L1 (Manhattan) geodesic distance from the given sources.
/// </summary>
/// <param name="grid"></param>
/// <param name="sources"></param>
/// <param name="result"></param>
/// <param name="exclude"></param>
public static void CalculateL1(Grid2d grid, IEnumerable <int> sources, double[] result, IEnumerable <int> exclude = null)
{
// impl ref
// http://www.numerical-tours.com/matlab/fastmarching_0_implementing/
(var nx, var ny) = grid.Count;
(var dx, var dy) = Vector2d.Abs(grid.Scale);
var queue = new Queue <int>();
result.SetRange(double.PositiveInfinity, grid.CountXY);
// enqueue sources
foreach (int i in sources)
{
result[i] = 0.0;
queue.Enqueue(i);
}
// exclude
if (exclude != null)
{
foreach (int i in exclude)
{
result[i] = 0.0;
}
}
// breadth first search from sources
while (queue.Count > 0)
{
int i0 = queue.Dequeue();
var d0 = result[i0];
(int x0, int y0) = grid.ToGridSpace(i0);
// -x
if (x0 > 0)
{
TryUpdate(d0 + dx, i0 - 1);
}
// +x
if (x0 < nx - 1)
{
TryUpdate(d0 + dx, i0 + 1);
}
// -y
if (y0 > 0)
{
TryUpdate(d0 + dy, i0 - nx);
}
// +y
if (y0 < ny - 1)
{
TryUpdate(d0 + dy, i0 + nx);
}
// add to queue if less than current min
void TryUpdate(double distance, int index)
{
if (distance < result[index])
{
result[index] = distance;
queue.Enqueue(index);
}
}
}
}
/// <summary>
///
/// </summary>
/// <param name="other"></param>
public GridField2dDouble(Grid2d other)
: base(other)
{
}
/// <inheritdoc />
public override GridField2d <double> Create(Grid2d grid)
{
return(new GridField2dDouble(grid));
}
/// <summary>
///
/// </summary>
/// <param name="other"></param>
public GridField2dVector2d(Grid2d other)
: base(other)
{
}
/// <inheritdoc />
public override GridField2d <Vector2d> Create(Grid2d grid)
{
return(new GridField2dVector2d(grid));
}
/// <summary> /// /// </summary> /// <param name="grid"></param> /// <returns></returns> public abstract GridField2d <T> Create(Grid2d grid);
