3D数组中的ArrayIndexOutOfBoundsException

Question

I'm trying to make a jagged array for a neural network and this is giving me an out of bounds error...

int[] sizes = {
    layer1, layer2, layer3
};
int k = sizes.length - 1;
double[][][] net = new double[k][][];
int i;
for (i = 0; i < k; i++)
   net[i] = new double[sizes[i]][];
for (int j = 0; j < sizes[i]; j++)
   net[i][j] = new double[sizes[i + 1]];

The size of y in net[x][ ][y] should be equal to the size of net[x+1][y][ ] .

I did it on paper and I thought that this would work.

Answer 1

int[] sizes = {
    layer1, layer2, layer3
};
int k = sizes.length - 1;

So, k is equal to 2.

int i;
for (i = 0; i < k; i++)
   net[i] = new double[sizes[i]][];

After that loop i is equal to 2.

for (int j = 0; j < sizes[i]; j++)
   net[i][j] = new double[sizes[i + 1]];
                          ^^^^^^^^^^^^
                          ArrayIndexOutOfBoundsException

Boom, sizes[i + 1] throws ArrayIndexOutOfBoundsException , since sizes has only indices 0, 1 and 2 and you are referring to sizes[3] .