/// <summary>
/// Check if the move is valid, i.e. not colliding into walls or other agents.
/// </summary>
/// <param name="possibleMove">The proposed move (to check if it is valid)</param>
/// <param name="agentNum">The index of the agent that is proposed to perform the move</param>
/// <param name="previousAgentMoves">A collection of moves that will be done by the other agents</param>
/// <returns></returns>
private bool IsValid(Move possibleMove, int agentNum, ICollection <Move> previousAgentMoves)
{
// If the tile is not free (out of the grid or with an obstacle)
if (m_Problem.IsValid(possibleMove) == false)
{
return(false);
}
// If previous move of another agent will collide with this move
if (previousAgentMoves.Contains(possibleMove) || previousAgentMoves.Contains(possibleMove.GetOppositeMove()))
{
return(false);
}
return(true);
}
private void Generate
(
MAM_AgentState node,
MAM_AgentState child
)
{
if (expandedNodes.Contains(child))
{
return;
}
Move childMove = child.lastMove;
if (!instance.IsValid(childMove)) // Not a valid location
{
return;
}
if (!closed(child))
{
if (child.f >= getBestCost())
{
return;
}
child.numOfAgentsInBestHeuristic = instance.m_vAgents.Length;
if (openList.Contains(child))
{
child.h = ((MAM_AgentState)openList.Get(child)).h;
child.heuristics = ((MAM_AgentState)openList.Get(child)).heuristics;
}
else
{
CalculateH(child, node);
}
CalculateF(child);
openList.Add(child);
UpdateBestCost(child);
nodesGenerated++;
}
}
/// <summary>
/// Generates a problem instance based on a DAO map file.
/// TODO: Fix code dup with GenerateProblemInstance and Import later.
/// </summary>
/// <param name="agentsNum"></param>
/// <returns></returns>
public ProblemInstance GenerateDragonAgeProblemInstance(string mapFileName, int agentsNum)
{
/**
* Randomization based on timer is disabled for purposes of getting
* reproducible experiments.
*/
//Random rand = new Random();
m_mapFileName = mapFileName;
m_agentNum = agentsNum;
TextReader input = new StreamReader(mapFileName);
string[] lineParts;
string line;
line = input.ReadLine();
Debug.Assert(line.StartsWith("type octile"));
// Read grid dimensions
line = input.ReadLine();
lineParts = line.Split(' ');
Debug.Assert(lineParts[0].StartsWith("height"));
int maxX = int.Parse(lineParts[1]);
line = input.ReadLine();
lineParts = line.Split(' ');
Debug.Assert(lineParts[0].StartsWith("width"));
int maxY = int.Parse(lineParts[1]);
line = input.ReadLine();
Debug.Assert(line.StartsWith("map"));
bool[][] grid = new bool[maxX][];
char cell;
for (int i = 0; i < maxX; i++)
{
grid[i] = new bool[maxY];
line = input.ReadLine();
for (int j = 0; j < maxY; j++)
{
cell = line.ElementAt(j);
if (cell == '@' || cell == 'O' || cell == 'T' || cell == 'W' /* Water isn't traversable from land */)
{
grid[i][j] = true;
}
else
{
grid[i][j] = false;
}
}
}
int x;
int y;
Agent[] agentGoals = new Agent[agentsNum];
AgentState[] agentStates = new AgentState[agentsNum];
bool[][] goals = new bool[maxX][];
for (int i = 0; i < maxX; i++)
{
goals[i] = new bool[maxY];
}
// Choose random valid unclaimed goal locations
for (int i = 0; i < agentsNum; i++)
{
x = rand.Next(maxX);
y = rand.Next(maxY);
if (goals[x][y] || grid[x][y])
{
i--;
}
else
{
goals[x][y] = true;
agentGoals[i] = new Agent(x, y, i);
}
}
// Select random start/goal locations for every agent by performing a random walk
for (int i = 0; i < agentsNum; i++)
{
agentStates[i] = new AgentState(agentGoals[i].Goal.x, agentGoals[i].Goal.y, agentGoals[i]);
}
ProblemInstance problem = new ProblemInstance();
problem.parameters[ProblemInstance.GRID_NAME_KEY] = Path.GetFileNameWithoutExtension(mapFileName);
problem.Init(agentStates, grid);
for (int j = 0; j < RANDOM_WALK_STEPS; j++)
{
for (int i = 0; i < agentsNum; i++)
{
goals[agentStates[i].lastMove.x][agentStates[i].lastMove.y] = false; // We're going to move the goal somewhere else
// Move in a random legal direction:
while (true)
{
Move.Direction op = (Move.Direction)rand.Next(0, 5); // TODO: fixme
agentStates[i].lastMove.Update(op);
if (problem.IsValid(agentStates[i].lastMove) &&
!goals[agentStates[i].lastMove.x][agentStates[i].lastMove.y]) // This spot isn't another agent's goal
{
break;
}
else
{
agentStates[i].lastMove.setOppositeMove(); // Rollback
}
}
goals[agentStates[i].lastMove.x][agentStates[i].lastMove.y] = true; // Claim agent's new goal
}
}
// Zero the agents' timesteps
foreach (AgentState agentStart in agentStates)
{
agentStart.lastMove.time = 0;
}
return(problem);
}
/// <summary>
/// Generates a problem instance, including a board, start and goal locations of desired number of agents
/// and desired precentage of obstacles
/// TODO: Refactor to use operators.
/// </summary>
/// <param name="gridSize"></param>
/// <param name="agentsNum"></param>
/// <param name="obstaclesNum"></param>
/// <returns></returns>
public ProblemInstance GenerateProblemInstance(int gridSize, int agentsNum, int obstaclesNum)
{
m_mapFileName = "GRID" + gridSize + "X" + gridSize;
m_agentNum = agentsNum;
/**
* Randomization based on timer is disabled for purposes of getting
* reproducible experiments.
*/
//Random rand = new Random();
if (agentsNum + obstaclesNum + 1 > gridSize * gridSize)
{
throw new Exception("Not enough room for " + agentsNum + ", " + obstaclesNum + " and one empty space in a " + gridSize + "x" + gridSize + "map.");
}
int x;
int y;
Agent[] aGoals = new Agent[agentsNum];
AgentState[] aStart = new AgentState[agentsNum];
bool[][] grid = new bool[gridSize][];
bool[][] goals = new bool[gridSize][];
// Generate a random grid
for (int i = 0; i < gridSize; i++)
{
grid[i] = new bool[gridSize];
goals[i] = new bool[gridSize];
}
for (int i = 0; i < obstaclesNum; i++)
{
x = rand.Next(gridSize);
y = rand.Next(gridSize);
if (grid[x][y]) // Already an obstacle
{
i--;
}
grid[x][y] = true;
}
// Choose random goal locations
for (int i = 0; i < agentsNum; i++)
{
x = rand.Next(gridSize);
y = rand.Next(gridSize);
if (goals[x][y] || grid[x][y])
{
i--;
}
else
{
goals[x][y] = true;
aGoals[i] = new Agent(x, y, i);
}
}
// Select random start/goal locations for every agent by performing a random walk
for (int i = 0; i < agentsNum; i++)
{
aStart[i] = new AgentState(aGoals[i].Goal.x, aGoals[i].Goal.y, aGoals[i]);
}
// Initialized here only for the IsValid() call. TODO: Think how this can be sidestepped elegantly.
ProblemInstance problem = new ProblemInstance();
problem.Init(aStart, grid);
for (int j = 0; j < RANDOM_WALK_STEPS; j++)
{
for (int i = 0; i < agentsNum; i++)
{
goals[aStart[i].lastMove.x][aStart[i].lastMove.y] = false; // We're going to move the goal somewhere else
while (true)
{
Move.Direction op = (Move.Direction)rand.Next(0, 5); // TODO: fixme
aStart[i].lastMove.Update(op);
if (problem.IsValid(aStart[i].lastMove) &&
!goals[aStart[i].lastMove.x][aStart[i].lastMove.y]) // this spot isn't another agent's goal
{
break;
}
else
{
aStart[i].lastMove.setOppositeMove(); // Rollback
}
}
goals[aStart[i].lastMove.x][aStart[i].lastMove.y] = true; // Claim agent's new goal
}
}
// Zero the agents' timesteps
foreach (AgentState agentStart in aStart)
{
agentStart.lastMove.time = 0;
}
// TODO: There is some repetition here of previous instantiation of ProblemInstance. Think how to elegantly bypass this.
problem = new ProblemInstance();
problem.Init(aStart, grid);
return(problem);
}