I am pretty sure that I have initialised everything, but it still throws
"Object reference not set to an instance of an object."
Cell[,] cell;
bool[,] UpdateCell;
int AreaSizeX;
int AreaSizeY;
int MaxAge;
public void Reset(int areaSizeX, int areaSizeY, int maxAge)
{
AreaSizeX = areaSizeX;
AreaSizeY = areaSizeY;
MaxAge = maxAge;
cell = new Cell[AreaSizeX, AreaSizeY];
UpdateCell = new bool[AreaSizeX, AreaSizeY];
for (int i = 0; i < areaSizeX; i++)
{
for (int j = 0; j < areaSizeY; j++)
{
cell[i, j].Alive = false; //throws exception here #########
cell[i, j].Age = 0;
UpdateCell[i, j] = false;
}
}
}
What is wrong in this code? C# does not allow dynamic array creation?
I assume Cell is a class (a reference type). That means the elements of the array are references. You're creating an array, but all the elements will be null by default -. You probably want:
for (int i = 0; i < areaSizeX; i++)
{
for (int j = 0; j < areaSizeY; j++)
{
cell[i, j] = new Cell();
cell[i, j].Alive = false;
cell[i, j].Age = 0;
UpdateCell[i, j] = false;
}
}
Or you could give your Cell class a constructor taking the age and liveness:
for (int i = 0; i < areaSizeX; i++)
{
for (int j = 0; j < areaSizeY; j++)
{
cell[i, j] = new Cell(false, 0);
UpdateCell[i, j] = false;
}
}
Or use an object initializer to set the properties:
for (int i = 0; i < areaSizeX; i++)
{
for (int j = 0; j < areaSizeY; j++)
{
cell[i, j] = new Cell { Alive = false, Age = 0};
UpdateCell[i, j] = false;
}
}
Related
There was an error not only that the execution window did not appear, but also that nothing appeared in the error window. I searched for the cause by annotating it. The equal function made a mistake, and I don't know why.
for (int i = 0; i < 3; i++)
{
do
{
randQuestion = r.Next(0, 5);
}
while (equal(beforeQ, randQuestion));
randQuestion = r.Next(0, 5);
for (int j = 1; j < 5; j++)
{
do
{
randBogi = r.Next(1, 5);
}
while (equal(beforeB, randBogi));
beforeB[j - 1] = randBogi;
R_Question[i, j] = Question[randQuestion, randBogi];
}
}
bool equal(int[] before, int rand)
{
for (int k = 0; k < before.Length ; k++)
{
if (before[k].Equals(rand))
{
return true;
}
}
return false;
}
Is there any relation between number of neurons and ability of Hopfield network to recognize patterns?
I write neural network program in C# to recognize patterns with Hopfield network. My network has 64 neurons. When I train network for 2 patterns, every things work nice and easy, but when I train network for more patterns, Hopfield can't find answer!
So, according to my code, how can I use Hopfield network to learn more patterns?
Should I make changes in this code?
There is my train() function:
public void Train(bool[,] pattern)
{
//N is number of rows in our square matrix
//Convert input pattern to bipolar
int[,] PatternBipolar = new int[N, N];
for (int i = 0; i < N; i++)
for (int j = 0; j < N; j++)
{
if (pattern[i, j] == true)
{
PatternBipolar[i, j] = 1;
}
else
{
PatternBipolar[i, j] = -1;
}
}
//convert to row matrix
int count1 = 0;
int[] RowMatrix = new int[(int)Math.Pow(N, 2)];
for (int j = 0; j < N; j++)
for (int i = 0; i < N; i++)
{
RowMatrix[count1] = PatternBipolar[i, j];
count1++;
}
//convert to column matrix
int count2 = 0;
int[] ColMatrix = new int[(int)Math.Pow(N, 2)];
for (int j = 0; j < N; j++)
for (int i = 0; i < N; i++)
{
ColMatrix[count2] = PatternBipolar[i, j];
count2++;
}
//multiplication
int[,] MultipliedMatrix = new int[(int)Math.Pow(N, 2), (int)Math.Pow(N, 2)];
for (int i = 0; i < (int)Math.Pow(N, 2); i++)
for (int j = 0; j < (int)Math.Pow(N, 2); j++)
{
MultipliedMatrix[i, j] = ColMatrix[i] * RowMatrix[j];
}
//cells in the northwest diagonal get set to zero
for (int i = 0; i < (int)Math.Pow(N, 2); i++)
MultipliedMatrix[i, i] = 0;
// WightMatrix + MultipliedMatrix
for (int i = 0; i < (int)Math.Pow(N, 2); i++)
for (int j = 0; j < (int)Math.Pow(N, 2); j++)
{
WeightMatrix[i, j] += MultipliedMatrix[i, j];
}
And there is Present() function (this function is used to return answer for a given pattern):
public void Present(bool[,] Pattern)
{
int[] output = new int[(int)(int)Math.Pow(N, 2)];
for (int j = 0; j < N; j++)
for (int i = 0; i < N; i++)
{
OutputShowMatrix[i, j] = 0;
}
//convert bool to binary
int[] PatternBinary = new int[(int)Math.Pow(N, 2)];
int count = 0;
for (int j = 0; j < N; j++)
for (int i = 0; i < N; i++)
{
if (Pattern[i, j] == true)
{
PatternBinary[count] = 1;
}
else
{
PatternBinary[count] = 0;
}
count++;
}
count = 0;
int activation = 0;
for (int j = 0; j < (int)Math.Pow(N, 2); j++)
{
for (int i = 0; i < (int)Math.Pow(N, 2); i++)
{
activation = activation + (PatternBinary[i] * WeightMatrix[i, j]);
}
if (activation > 0)
{
output[count] = 1;
}
else
{
output[count] = 0;
}
count++;
activation = 0;
}
count = 0;
for (int j = 0; j < N; j++)
for (int i = 0; i < N; i++)
{
OutputShowMatrix[i, j] = output[count++];
}
In below images I trained Hopfield for characters A and P and when input patterns are like A or P, network recognize them in true way
Then I train it for character C:
This is where every things go wrong!
Now if I enter pattern like C, this issue happen:
And if enter pattern like A, see what happen:
And if train more patterns, whole of grid become black!
I've spotted only one mistake in your code: you perform only one iteration of node value calculation, without verifying if the values have converged. I've fixed this method like this:
public bool[,] Present(bool[,] pattern)
{
bool[,] result = new bool[N, N];
int[] activation = new int[N * N];
int count = 0;
for (int i = 0; i < N; i++)
for (int j = 0; j < N; j++)
{
activation[count++] = pattern[i, j] ? 1 : 0;
}
bool convergence = false;
while (!convergence)
{
convergence = true;
var previousActivation = (int[])activation.Clone();
for (int i = 0; i < N * N; i++)
{
activation[i] = 0;
for (int j = 0; j < N * N; j++)
{
activation[i] += (previousActivation[j] * WeightMatrix[i, j]);
}
activation[i] = activation[i] > 0 ? 1 : 0;
if (activation[i] != previousActivation[i])
{
convergence = false;
}
}
}
count = 0;
for (int i = 0; i < N; i++)
for (int j = 0; j < N; j++)
{
result[i, j] = activation[count++] == 1;
}
return result;
}
This slightly improves the results, however probably should also be improved to calculate the values asynchronously to avoid cycles.
Unfortunately, this still introduces the behaviour you've described. This is results from the phenomena called spurious patterns. For the network to learn more than one pattern consider training it with a Hebb rule. You can read about the spurious patterns, stability and learning of the Hopfield network here and here.
char[,] map = new char[10, 20];
for (int i = 0; i < map.GetLength(0); i++)
{
for (int j = 0; i < map.GetLength(1); j++)
map[i, j] = '.';
}
I just simply want to make all the elements of map[i,j] to be a point , but always when I try to run it the compiler says: Index out of range exception. Maybe it's a stupid question but I had to ask it.
See the i in your j-loop
for (int j = 0; j < map.GetLength(1); j++)
You use i instead of j look at this:
char[,] map = new char[10, 20];
for (int i = 0; i < map.GetLength(0); i++)
{
for (int j = 0; j < map.GetLength(1); j++)
{
map[i, j] = '.';
}
}
I need to calculate matrix: ( X^(T) * X )^(-1).
Legend for the code&comments:
x is double[,] array;
xT - transposed matrix
^(-1) - inverted matrix
Every time i generate new random matrix to work with it and i found out that program is very unstable, because it isn't working properly with any input data. I'm sure about that because i need to get Identity matrix in the end if everything's fine, but sometimes i get a totally terrible Ineverted matrix so i don't get an Identity matrix. I'm dissappointes because i always use the same type of data and do not convert anything. Compiler is MVS 2010. Hope You will help me.
Here is my Program.cs:
static void Main(string[] args)
{
Matrix x = new Matrix(5, 4);
//Matrix temp = new Matrix(x.Row, x.Col);
//double[] y = new double[x.Row];
//double[] b = new double[x.Row];
//this data isn't calculated correctly. used for debugging
x.MatrixX[0, 0] = 7; x.MatrixX[0, 1] = 6; x.MatrixX[0, 2] = 5; x.MatrixX[0, 3] = 8;
x.MatrixX[1, 0] = 7; x.MatrixX[1, 1] = 5; x.MatrixX[1, 2] = 8; x.MatrixX[1, 3] = 5;
x.MatrixX[2, 0] = 6; x.MatrixX[2, 1] = 8; x.MatrixX[2, 2] = 6; x.MatrixX[2, 3] = 8;
x.MatrixX[3, 0] = 8; x.MatrixX[3, 1] = 5; x.MatrixX[3, 2] = 8; x.MatrixX[3, 3] = 7;
x.MatrixX[4, 0] = 8; x.MatrixX[4, 1] = 5; x.MatrixX[4, 2] = 6; x.MatrixX[4, 3] = 7;
/*
7,00000 6,00000 5,00000 8,00000
7,00000 5,00000 8,00000 5,00000
6,00000 8,00000 6,00000 8,00000
8,00000 5,00000 8,00000 7,00000
8,00000 5,00000 6,00000 7,00000
*/
//random matrix generation
/*
Random rnd = new Random();
for (int i = 0; i < x.Row; i++)
for (int j = 0; j < x.Col; j++)
x.MatrixX[i, j] = rnd.Next(5, 10);
*/
/*i'm going to calculate: ( X^(T) * X )^(-1)
* 1. transpose X
* 2. multiply X and (1)
* 3. invert matrix (2)
* +4. i wanna check the results: Multilate of (2) and (3) = Identity_matrix.
* */
Matrix.Display(x);
//1
Matrix xt = Matrix.Transpose(x);
Matrix.Display(xt);
//2
Matrix xxt = Matrix.Multiply(x, xt);
Matrix.Display(xxt);
//3
Matrix xxtinv = Matrix.Invert(Matrix.Multiply(x, xt));
Matrix.Display(xxtinv);
//4
Console.WriteLine("Invert(xxt) * xxt. IdentityMatrix:");
Matrix IdentityMatrix = Matrix.Multiply(xxtinv, xxt);
Matrix.Display(IdentityMatrix);
Console.ReadKey();
}
And here is Matrix.cs with all functions:
public class Matrix
{
private double[,] matrix;
private int row;
private int col;
#region constructors
public Matrix(int Row, int Col)
{
this.row = Row;
this.col = Col;
matrix = new double[Row, Col];
}
public Matrix()
{
Random rnd = new Random();
Row = rnd.Next(3, 7);
Col = rnd.Next(3, 7);
matrix = new double[Row, Col];
for (int i = 0; i < Row; i++)
for (int j = 0; j < Col; j++)
matrix[i, j] = rnd.Next(5, 10);
}
public Matrix(Matrix a)
{
this.Col = a.Col;
this.Row = a.Row;
this.matrix = a.matrix;
}
#endregion
#region properties
public int Col
{
get { return col; }
set { col = value; }
}
public int Row
{
get { return row; }
set { row = value; }
}
public double[,] MatrixX
{
get { return matrix; }
set { matrix = value; }
}
#endregion
static public Matrix Transpose(Matrix array)
{
Matrix temp = new Matrix(array.Col, array.Row);
for (int i = 0; i < array.Row; i++)
for (int j = 0; j < array.Col; j++)
temp.matrix[j, i] = array.matrix[i, j];
return temp;
}
static public void Display(Matrix array)
{
for (int i = 0; i < array.Row; i++)
{
for (int j = 0; j < array.Col; j++)
Console.Write("{0,5:f2}\t", array.matrix[i, j]);
Console.WriteLine();
}
Console.WriteLine();
}
static public Matrix Multiply(Matrix a, Matrix b)
{
if (a.Col != b.Row) throw new Exception("multiplication is impossible: a.Col != b.Row");
Matrix r = new Matrix(a.Row, b.Col);
for (int i = 0; i < a.Row; i++)
{
for (int j = 0; j < b.Col; j++)
{
double sum = 0;
for (int k = 0; k < b.Row; k++)
sum += a.matrix[i, k] * b.matrix[k, j];
r.matrix[i, j] = sum;
}
}
return r;
}
static public Matrix Invert(Matrix a)
{
Matrix E = new Matrix(a.Row, a.Col);
double temp = 0;
int n = a.Row;
for (int i = 0; i < n; i++)
for (int j = 0; j < n; j++)
{
E.matrix[i, j] = 0.0;
if (i == j)
E.matrix[i, j] = 1.0;
}
for (int k = 0; k < n; k++)
{
temp = a.matrix[k, k];
for (int j = 0; j < n; j++)
{
a.matrix[k, j] /= temp;
E.matrix[k, j] /= temp;
}
for (int i = k + 1; i < n; i++)
{
temp = a.matrix[i, k];
for (int j = 0; j < n; j++)
{
a.matrix[i, j] -= a.matrix[k, j] * temp;
E.matrix[i, j] -= E.matrix[k, j] * temp;
}
}
}
for (int k = n - 1; k > 0; k--)
{
for (int i = k - 1; i >= 0; i--)
{
temp = a.matrix[i, k];
for (int j = 0; j < n; j++)
{
a.matrix[i, j] -= a.matrix[k, j] * temp;
E.matrix[i, j] -= E.matrix[k, j] * temp;
}
}
}
for (int i = 0; i < n; i++)
for (int j = 0; j < n; j++)
{
a.matrix[i, j] = E.matrix[i, j];
}
return a;
}
}
In your example, the determinant of x * transpose(x) is zero. As a result, there is no inverse, which is probably why you're getting strange results.
I also note that your Inverse function modifies the matrix passed to it. This should probably be modified to avoid that.
I am getting this error...
Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index.
in the code at the indicated position.
List<int>[] tetangga = new List<int>[this.observasi];
for (int i = 0; i < this.observasi; i++)
{
tetangga[i] = new List<int>();
for (int j = 0; j < this.observasi; j++)
{
if (tableWeight[i, j] > 0)
{
tetangga[i].Add(j);
}
}
}
this.dataTable.ColumnCount = 2;
this.dataTable.Columns[0].HeaderCell.Value = "REGION";
this.dataTable.Columns[1].HeaderCell.Value = "REGION NEIGHBOR";
this.dataTable.Columns[1].SortMode = DataGridViewColumnSortMode.NotSortable;
this.dataTable.Columns[0].SortMode = DataGridViewColumnSortMode.NotSortable;
this.dataTable.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCells;
int jlhRow = 0;
for (int i = 0; i < this.observasi; i++)
{
jlhRow = jlhRow + tetangga[i].Count;
}
this.dataTable.RowCount = jlhRow;
int row = 0;
for (int k = 0; k < this.observasi; k++)
{
this.dataTable[0, row].Value = this.nameRegion[k]; // <-- error occurs here
for (int l = 0; l < tetangga[k].Count; l++)
{
this.dataTable[1, row].Value = this.nameRegion[tetangga[k][l]];
row++;
}
}
Can anyone explain to me why?
You problem is here
for (int j = 0; j < this.observasi; j++)
{
if (tableWeight[i, j] > 0)
{
tetangga[i].Add(j);
}
}
How do we know what the 2nd dimension of tableWeight is? I expect it does not go up to this.observasi.
Put a break point at the start of your loop, before the line:
this.dataTable[0, row].Value = this.nameRegion[k];
Examine dataTable and nameRegion in the debugger and you may answer your own question. It's likely that the collections do not contain elements at the indexes you are specifying.