I am having a hard time coming up with a good way of finding the sum of the neighbouring values in a 2d array. I need to find the sum of all neighbouring values at an index position. If the position is an edge, I need to transpose it's value into the sum. So every element will have 4 values contributing to its sum.
Example.
Element at index[0][0] = 5.0. [0][1] = 2, and [1][0] = 4. The sum of index[0][0] = 5(left/mirror of itself) + 5 (up/mirror of itself) + 2(right of it) + 4 (below it) = 16.
My code so far is below. Suggestions for a better way would be appreciated. This code is getting an
ArrayOutOfBounds: 3
on the line after the comment saying //ERROR**
Public static double [][] getSumWeight(double [][] map){
int base = 0;
//int count = getEnhancementLevel();
int row = map.length;
int col = map[0].length;
int newRow = row*2;
int newCol = col*2;
double [] [] sumMap = new double [row][col];
double [][] weightMap = new double [newRow][newCol];
//getting the corner sum weights
for (int i = 0; i < map.length; i++){
for (int j = 0; j < map[i].length; j++){
if (i == 0 && j == 0){
double result = 0;
result += (map[0][0])*2;
result += map[0][1];
result += map[1][0];
sumMap[0][0] = result;
System.out.println("corner" + sumMap[0][0]);
}
else if (i == 0 && j == map[0].length){
double result = 0;
result += map[0][map[0].length];
result += map[0][map[0].length-1];
result += map[1][map[0].length];
sumMap[i][j] = result;
}else if (i == map.length && j == 0){
}else if (i == map.length && j == map[map.length].length){
}
//getting the mid(s) of the top row
else if (i == 0 && j != 0 && j != map[0].length){
double result = 0;
result += map[i][j]; //top value or mirror
result += map[i][j-1]; // left value
//ERROR****
result += map[i][j+1]; // right value
result += map[i+1][j]; // bottom value
sumMap[i][j] = result;
}
//getting the mid(s) of the bottom row
else if (i == map.length && j != 0 && j != map[map.length].length){
double result = 0;
result += map[i][j];
result += map[i][j-1];
result += map[i][j+1];
result += map[i-1][j];
sumMap[i][j] = result;
}
//getting the mid(s) of the left most column
else if (j == 0 && i != 0 && i != map.length){
double result = 0;
result += map[i][j];
result += map[i-1][j];
result += map[i+1][j];
result += map[i][j+1];
sumMap[i][j] = result;
}
//getting the mid(s) of the right most column
else if (j == map[0].length && i != 0 && i != map.length){
double result = 0;
result += map[i][j];
result += map[i-1][j];
result += map[i+1][j];
result += map[i][j-1];
sumMap[i][j] = result;
}
//filling in all the remaining values
else{
double result = 0;
result += map[i-1][j];
result += map[i+1][j];
result += map[i][j-1];
result += map[i][j+1];
sumMap[i][j] = result;
}
}
}
for (int i = 0; i < map.length; i++){
for (int j = 0; j < map[i].length; j++){
System.out.println(sumMap[i][j]);
}}
return sumMap;
}
This is your solution. I know there are lots of if else statements but this is my best.
for(int i=0;i<a.length;i++){
for(int j=0;j<a[i].length;j++){
if(i==0){
if(j==0){
sum[i][j] = a[i][j]*2 + a[i+1][j] + a[i][j+1];
}
else if(j==a[i].length-1){
sum[i][j] = a[i][j]*2 + a[i][j-1] + a[i+1][j] ;
}
else{
sum[i][j] = a[i][j] + a[i][j-1] + a[i+1][j] + a[i][j+1];
}
}
else if(i==a.length-1){
if(j==0){
sum[i][j] = a[i][j]*2 + a[i-1][j] + a[i][j+1];
}
else if(j==a[i].length-1){
sum[i][j] = a[i][j]*2 + a[i][j-1] + a[i-1][j] ;
}
else{
sum[i][j] = a[i][j] + a[i][j-1] + a[i-1][j] + a[i][j+1];
}
}
else if(j==0){
sum[i][j] = a[i][j] + a[i-1][j] + a[i+1][j] + a[i][j+1];
}
else if(j==a[i].length-1){
sum[i][j] = a[i][j] + a[i-1][j] + a[i+1][j] + a[i][j-1];
}
else{
sum[i][j] = a[i][j-1] + a[i-1][j] + a[i+1][j] + a[i][j+1];
}
}
}