void Window::applyGaussianWindow (float *samples, const int numSamples)
{
const float sigma = 0.4f;
const int sizeMinusOne = numSamples - 1;
const double oneOverSize = (1.0 / numSamples);
windowFactor = 0.0f;
for (int i = 0; i < numSamples; i++)
{
// Gaussian window equation
float window = (float) (exp (-0.5 * squareNumber ((i - sizeMinusOne * 0.5) / (sigma * sizeMinusOne * 0.5))));
samples[i] *= window;
windowFactor += window;
}
windowFactor *= (float) oneOverSize;
}
void MazeSolver::dfsHelper(int r, int c, VisitedTracker &vt, std::vector<Direction> &p, int &numExplored){
Direction dir; // these variables change depending on direction of neighbour that will be explored
int rVal;
int cVal;
for(int i=0; i < 4; i++){
if(i==0){dir = RIGHT; rVal = r; cVal=c+1;}
else if(i==1){dir = LEFT; rVal = r; cVal=c-1;}
else if(i==2){dir = DOWN; rVal = r+1; cVal=c;}
else {dir = UP; rVal = r-1; cVal=c;}
if ( maze->canTravel(dir, r, c) && ! vt.isVisited(rVal,cVal))
{
p[squareNumber(rVal, cVal)] = dir; // set predecessor
vt.setVisited(rVal,cVal);
dfsHelper(rVal, cVal, vt, p, numExplored);
}
}
numExplored++;
}
std::vector<Direction> MazeSolver::pathCreator(std::vector<Direction> p){
std::vector<Direction> path;
std::stack<Direction> st;
int r = maze->getGoalRow();
int c = maze->getGoalCol();
while( r != maze->getStartRow() || c != maze->getStartCol())
{
st.push( p[ squareNumber(r,c) ]);
switch( st.top() )
{
case UP: r++; break; // yes, r++. I went up to get here...
case DOWN: r--; break;
case LEFT: c++; break;
case RIGHT: c--; break;
}
}
while ( ! st.empty() )
{
path.push_back(st.top());
st.pop();
}
return path;
}
void MazeSolver::solveByAStar(int choice)
{
// TODO:
// if choice is 1, solve by A* using heuristic of "return 0"
// else if choice is 2, solve by A* using heuristic of Manhattan Distance
// else if choice is 3, solve by A* using heuristic of Euclidean Distance
// else completely up to you.
if(choice > 3 || choice < 1) return;
int numSquares = maze->numRows() * maze->numCols();
double h[maze->numRows()][maze->numCols()]; // (estimated) distance from target, depends on heuristic
double g[maze->numRows()][maze->numCols()]; // will store g values (depth of path to current cell)
VisitedTracker vt(maze->numRows(), maze->numCols());
int numExplored = 0;
std::vector<Direction> p( numSquares ); // stores predecessors
//std::priority_queue<std::pair<std::pair<int, int>, double>,
// std::vector<std::pair<std::pair<int, int>, double>>, std::greater<int>> pq;
//fill up h array to store h[n] values for each cell
int tR = maze->getGoalRow(); // target Row coordinate
int tC = maze->getGoalCol(); // target Col coordinate
int sR = maze->getStartRow();
int sC = maze->getStartCol();
double d;
for(int i=0; i < maze->numRows(); i++){
for(int j=0; j < maze->numCols(); j++){
if(choice==1)d=0;
else if(choice==2){d = sqrt((tR-i)*(tR-i) + (tC-j)*(tC-j));}
else{d = std::abs((tR - i) + (tC - j));}
h[i][j] = d;
g[i][j] = -1.0; // set to -1 initially instead of garbage values
}
}
h[tR][tC] = 0.0; // heuristic distance to goal is 0
g[sR][sC] = 0.0; // depth of path from Start is 0
myPair = std::make_pair(std::make_pair(sR, sC), h[sR][sC]); // starting node/cell
pq.push(myPair);
while(!pq.empty()){
std::pair<std::pair<int, int>, double> v;
v = pq.top();
pq.pop();
if(vt.isVisited(v.first.first, v.first.second)) continue;
vt.setVisited(v.first.first, v.first.second);
int r = v.first.first;
int c = v.first.second;
// in each of the 4 cases, make sure then next node isn't the predecessor of the current node
if ( maze->canTravel(UP, r, c))
{
p[squareNumber(r-1, c)] = UP;
//vt.setVisited(r-1,c);
g[r-1][c] = g[r][c] + 1;
double f = h[r][c] + g[r-1][c];
std::pair<int, int>loc = std::make_pair(r-1, c);
pq.push(std::make_pair(loc, f));
}
// Note: this is NOT "else if" ...
if ( maze->canTravel(DOWN, r, c))
{
p[squareNumber(r+1, c)] = DOWN;
//vt.setVisited(r+1, c);
g[r+1][c] = g[r][c] + 1;
double f = h[r][c] + g[r+1][c];
std::pair<int, int>loc = std::make_pair(r+1, c);
pq.push(std::make_pair(loc, f));
}
if ( maze->canTravel(LEFT, r, c) )
{
p[squareNumber(r, c-1)] = LEFT;
//setVisited(r, c-1);
g[r][c-1] = g[r][c] + 1;
double f = h[r][c] + g[r][c-1];
std::pair<int, int>loc = std::make_pair(r, c-1);
pq.push(std::make_pair(loc, f));
}
if ( maze->canTravel(RIGHT, r, c) )
{
p[squareNumber(r, c+1)] = RIGHT;
//vt.setVisited(r, c+1);
g[r][c+1] = g[r][c] + 1;
double f = h[r][c] + g[r][c+1];
std::pair<int, int>loc = std::make_pair(r, c+1);
pq.push(std::make_pair(loc, f));
}
}
std::vector<Direction> path = pathCreator(p);
display->reportSolution(path, vt, numExplored);
}
void MazeSolver::solveByBFS()
{
/* In lecture on Tuesday March 22, we had a graph
with vertices numbered 0 to n-1, inclusive.
Instead, we have vertices with two numbers,
row and col, in the range:
[0, maze->numRows()-1], [0, maze->numCols() -1 ]
to assign each a unique number [0, maze->numRows() * maze->numCols() -1]
we will say that maze square (r,c) is really number
r * maze->numCols() + c
*/
int r, c;
int numSquares = maze->numRows() * maze->numCols();
VisitedTracker vt(maze->numRows(), maze->numCols());
std::vector<Direction> parent( numSquares ); // what was my immediate prior direction to get here?
int numExplored = 0;
vt.setVisited(maze->getStartRow(), maze->getStartCol());
std::queue<std::pair<int, int>> q;
q.push(std::pair<int,int>(maze->getStartRow(), maze->getStartCol()));
while( ! q.empty() )
{
std::pair<int, int> v = q.front();
q.pop();
numExplored++;
r = v.first;
c = v.second;
/* This one if statement is different from the pseudo-code provided
in lecture, because we want to stop when we've reached the goal.
The code provided in lecture was for if you wanted to do a BFS
that explored the entire graph.
*/
if( r == maze->getGoalRow() && c == maze->getGoalCol() )
{
std::vector<Direction> path;
std::stack<Direction> st;
while( r != maze->getStartRow() || c != maze->getStartCol())
{
st.push( parent[ squareNumber(r,c) ]);
switch( st.top() )
{
case UP: r++; break; // yes, r++. I went up to get here...
case DOWN: r--; break;
case LEFT: c++; break;
case RIGHT: c--; break;
}
}
while ( ! st.empty() )
{
path.push_back(st.top());
st.pop();
}
display->reportSolution(path, vt, numExplored);
return;
}
/*
* Now we're back to code that looks like the pseudo-code you've seen.
* The difference here is that we aren't keeping track of distances;
that's similar to the difference above. You could add, and ignore,
the vector that would result if you wanted to do so.
*/
if ( maze->canTravel(UP, r, c) && ! vt.isVisited(r-1,c))
{
parent[squareNumber(r-1, c)] = UP;
vt.setVisited(r-1,c);
q.push(std::pair<int,int>(r-1, c));
}
// Note: this is NOT "else if" ...
if ( maze->canTravel(DOWN, r, c) && ! vt.isVisited(r+1,c) )
{
parent[squareNumber(r+1, c)] = DOWN;
vt.setVisited(r+1, c);
q.push(std::pair<int,int>(r+1, c));
}
if ( maze->canTravel(LEFT, r, c) && ! vt.isVisited(r,c-1) )
{
parent[squareNumber(r, c-1)] = LEFT;
vt.setVisited(r, c-1);
q.push(std::pair<int,int>(r, c-1));
}
if ( maze->canTravel(RIGHT, r, c) && ! vt.isVisited(r, c+1) )
{
parent[squareNumber(r, c+1)] = RIGHT;
vt.setVisited(r, c+1);
q.push(std::pair<int,int>(r, c+1));
}
}
}
