public void PutInRightOrder(Matrica P)
{
for (int i = 0; i < P.NoOfColumns; i++)
{
for (int j = 0; j < P.NoOfRows; j++)
{
if (P.LoadedMatrix[j][i] == 1 && i != j)
{
this.SwitchRows(j, i);
break;
}
}
}
}
/// <summary>
/// Checks if two matrices are equal.
/// </summary>
/// <param name="matrix">One of the matrices used in comparing.</param>
public void Equals(Matrica matrix)
{
this.NoOfRows = matrix.NoOfRows;
this.NoOfColumns = matrix.NoOfColumns;
for (int i = 0; i < this.NoOfRows; i++)
{
List <double> row = new List <double>();
for (int j = 0; j < this.NoOfColumns; j++)
{
row.Insert(j, matrix.LoadedMatrix[i][j]);
}
this.LoadedMatrix.Add(i, row);
}
}
/// <summary>
/// Subtracts matrix B to matrix A and saves value to matrix A.
/// </summary>
/// <param name="matrix">Matrix being subtracted from another matrix.</param>
public void SubtractValue(Matrica matrix)
{
if (this.NoOfRows != matrix.NoOfRows || this.NoOfColumns != matrix.NoOfColumns)
{
throw new ArgumentException("Matrice koje želite oduzeti nisu odgovarajućih dimenzija za ovu operaciju!");
}
for (int i = 0; i < this.NoOfRows; i++)
{
for (int j = 0; j < this.NoOfColumns; j++)
{
this.LoadedMatrix[i][j] -= matrix.LoadedMatrix[i][j];
}
}
}
/// <summary>
/// Subtracts matrix B to matrix A and saves value to matrix A.
/// </summary>
/// <param name="matrix">Matrix being subtracted from another matrix.</param>
public void SubtractValue(Matrica matrix)
{
if (this.NoOfRows != matrix.NoOfRows || this.NoOfColumns != matrix.NoOfColumns)
{
throw new ArgumentException("Matrices you want to subtract do not have compatible dimensions for this operation!");
}
for (int i = 0; i < this.NoOfRows; i++)
{
for (int j = 0; j < this.NoOfColumns; j++)
{
this.LoadedMatrix[i][j] -= matrix.LoadedMatrix[i][j];
}
}
}
public static Matrica ArrayToVector(double[] array)
{
Matrica result = new Matrica();
result.NoOfRows = array.Length;
result.NoOfColumns = 1;
for (int i = 0; i < array.Length; i++)
{
List <double> row = new List <double>();
row.Insert(0, array[i]);
result.LoadedMatrix.Add(i, row);
}
return(result);
}
public Matrica MultiplyByScalar2(double scalar)
{
Matrica result = new Matrica();
result.Equals(this);
for (int i = 0; i < result.NoOfRows; i++)
{
for (int j = 0; j < result.NoOfColumns; j++)
{
result.LoadedMatrix[i][j] *= scalar;
}
}
return(result);
}
/// <summary>
/// Solves forward substitution.
/// </summary>
/// <param name="LU">Matrix containing both L and U matrices obtained from decomposition.</param>
/// <param name="b">Vector containing values from the right side of system of linear equations.</param>
/// <returns>Vector y.</returns>
public static Matrica ForwardSubstitution(Matrica LU, Matrica b)
{
if (LU.NoOfRows != LU.NoOfColumns || LU.NoOfRows != b.NoOfRows)
{
throw new ArgumentException("Dimenzije matrica nisu odgovarajuće! Provjerite i pokušajte ponovno.");
}
for (int i = 0; i < b.NoOfRows - 1; i++)
{
for (int j = i + 1; j < b.NoOfRows; j++)
{
b.LoadedMatrix[j][0] -= LU.LoadedMatrix[j][i] * b.LoadedMatrix[i][0];
}
}
return(b);
}
/// <summary>
/// Solves forward substitution.
/// </summary>
/// <param name="LU">Matrix containing both L and U matrices obtained from decomposition.</param>
/// <param name="b">Vector containing values from the right side of system of linear equations.</param>
/// <returns>Vector y.</returns>
public static Matrica ForwardSubstitution(Matrica LU, Matrica b)
{
if (LU.NoOfRows != LU.NoOfColumns || LU.NoOfRows != b.NoOfRows)
{
throw new ArgumentException("Matrices do not have compatible dimensions! Check the matrices and try again.");
}
for (int i = 0; i < b.NoOfRows - 1; i++)
{
for (int j = i + 1; j < b.NoOfRows; j++)
{
b.LoadedMatrix[j][0] -= LU.LoadedMatrix[j][i] * b.LoadedMatrix[i][0];
}
}
return(b);
}
public void PutVectorColumnInInverseMatrixAtIndex(int index, Matrica vector)
{
for (int i = 0; i < this.NoOfRows; i++)
{
List <double> row;
if (index == 0)
{
row = new List <double>();
}
else
{
row = this.LoadedMatrix[i];
}
row.Insert(index, vector.LoadedMatrix[i][0]);
this.LoadedMatrix[i] = row;
}
}
/// <summary>
/// Transposes the matrix.
/// </summary>
/// <returns>Transposed matrix.</returns>
public Matrica TransposeMatrix()
{
Matrica result = new Matrica();
result.NoOfRows = this.NoOfColumns;
result.NoOfColumns = this.NoOfRows;
for (int i = 0; i < this.NoOfColumns; i++)
{
List <double> row = new List <double>();
for (int j = 0; j < this.NoOfRows; j++)
{
row.Insert(j, this.LoadedMatrix[j][i]);
}
result.LoadedMatrix.Add(i, row);
}
return(result);
}
/// <summary>
/// Checks if two matrices are equal.
/// </summary>
/// <param name="matrix">Matrix used in comparing.</param>
/// <param name="epsilon">Constant used in comparing two values.</param>
/// <returns>Returns true if equal, false if not equal.</returns>
public bool IsEqual(Matrica matrix, double epsilon)
{
if (this.NoOfRows != matrix.NoOfRows || this.NoOfColumns != matrix.NoOfColumns)
{
return(false);
}
for (int i = 0; i < this.NoOfRows; i++)
{
for (int j = 0; j < this.NoOfColumns; j++)
{
if (Math.Abs(this.LoadedMatrix[i][j] - matrix.LoadedMatrix[i][j]) > epsilon)
{
return(false);
}
}
}
return(true);
}
/// <summary>
/// Solves backward substitution.
/// </summary>
/// <param name="LU">Matrix containing both L and U matrices obtained from decomposition.</param>
/// <param name="b">Vector containing values from the right side of system of linear equations.</param>
/// <param name="epsilon">Constant used for checking if we are dividing value by zero.</param>
/// <returns>Vector x (result of solving system of linear equations).</returns>
public static Matrica BackwardSubstitution(Matrica LU, Matrica b, double epsilon)
{
if (LU.NoOfRows != LU.NoOfColumns || LU.NoOfRows != b.NoOfRows)
{
throw new ArgumentException("Matrices do not have compatible dimensions! Check the matrices and try again.");
}
for (int i = b.NoOfRows - 1; i >= 0; i--)
{
if (Math.Abs(LU.LoadedMatrix[i][i]) <= epsilon)
{
throw new DivideByZeroException("It is not possible to divide by zero!!");
}
b.LoadedMatrix[i][0] /= LU.LoadedMatrix[i][i];
for (int j = 0; j <= i - 1; j++)
{
b.LoadedMatrix[j][0] -= LU.LoadedMatrix[j][i] * b.LoadedMatrix[i][0];
}
}
return(b);
}
/// <summary>
/// Solves backward substitution.
/// </summary>
/// <param name="LU">Matrix containing both L and U matrices obtained from decomposition.</param>
/// <param name="b">Vector containing values from the right side of system of linear equations.</param>
/// <param name="epsilon">Constant used for checking if we are dividing value by zero.</param>
/// <returns>Vector x (result of solving system of linear equations).</returns>
public static Matrica BackwardSubstitution(Matrica LU, Matrica b, double epsilon)
{
if (LU.NoOfRows != LU.NoOfColumns || LU.NoOfRows != b.NoOfRows)
{
throw new ArgumentException("Dimenzije matrica nisu odgovarajuće! Provjerite i pokušajte ponovno.");
}
for (int i = b.NoOfRows - 1; i >= 0; i--)
{
if (Math.Abs(LU.LoadedMatrix[i][i]) <= epsilon)
{
throw new DivideByZeroException("Nije moguće dijeliti s nulom!!");
}
b.LoadedMatrix[i][0] /= LU.LoadedMatrix[i][i];
for (int j = 0; j <= i - 1; j++)
{
b.LoadedMatrix[j][0] -= LU.LoadedMatrix[j][i] * b.LoadedMatrix[i][0];
}
}
return(b);
}
/// <summary>
/// Executes LUP decomposition.
/// </summary>
/// <param name="epsilon">Constant used for checking if the pivot element is equal to zero.</param>
/// <param name="b">Vector containing values from the right side of system of linear equations.</param>
/// <returns>Permutated identity matrix P.</returns>
public Matrica LUPDecomposition(double epsilon, Matrica b)
{
if (this.NoOfRows != this.NoOfColumns)
{
throw new ArgumentException("Ne možete izvršiti LU dekompoziciju nad matricom koja nije kvadratna!");
}
Matrica identityMatrixP = GenerateIdentityMatrix(this.NoOfRows);
int pivotElementRow;
for (int i = 0; i < this.NoOfColumns - 1; i++)
{
pivotElementRow = this.ChoosePivotElement(i, i);
if (Math.Abs(this.LoadedMatrix[pivotElementRow][i]) <= epsilon)
{
throw new DivideByZeroException("Stožerni element je manji od ili jednak vrijednosti " + epsilon + ". Nije moguće riješiti ovaj sustav pomoću LUP dekompozicije.");
}
identityMatrixP.SwitchRows(i, pivotElementRow);
this.SwitchRows(i, pivotElementRow);
b.SwitchRows(i, pivotElementRow);
for (int j = i + 1; j < this.NoOfRows; j++)
{
if (Math.Abs(this.LoadedMatrix[i][i]) <= epsilon)
{
throw new DivideByZeroException("Nije moguće dijeliti s nulom!!");
}
this.LoadedMatrix[j][i] /= this.LoadedMatrix[i][i];
for (int k = i + 1; k < this.NoOfColumns; k++)
{
this.LoadedMatrix[j][k] -= this.LoadedMatrix[j][i] * this.LoadedMatrix[i][k];
}
}
}
return(identityMatrixP);
}
/// <summary>
/// Executes LUP decomposition.
/// </summary>
/// <param name="epsilon">Constant used for checking if the pivot element is equal to zero.</param>
/// <param name="b">Vector containing values from the right side of system of linear equations.</param>
/// <returns>Permutated identity matrix P.</returns>
public Matrica LUPDecomposition(double epsilon, Matrica b)
{
if (this.NoOfRows != this.NoOfColumns)
{
throw new ArgumentException("It is not possible to execute LU decomposition over the nonsquare matrix!");
}
Matrica identityMatrixP = GenerateIdentityMatrix(this.NoOfRows);
int pivotElementRow;
for (int i = 0; i < this.NoOfColumns - 1; i++)
{
pivotElementRow = this.ChoosePivotElement(i, i);
if (Math.Abs(this.LoadedMatrix[pivotElementRow][i]) <= epsilon)
{
throw new DivideByZeroException("Pivot element is less than or equal to " + epsilon + ". Solve the linear equation system using the LUP decomposition.");
}
identityMatrixP.SwitchRows(i, pivotElementRow);
this.SwitchRows(i, pivotElementRow);
b.SwitchRows(i, pivotElementRow);
for (int j = i + 1; j < this.NoOfRows; j++)
{
if (Math.Abs(this.LoadedMatrix[i][i]) <= epsilon)
{
throw new DivideByZeroException("It is not possible to divide by zero!!");
}
this.LoadedMatrix[j][i] /= this.LoadedMatrix[i][i];
for (int k = i + 1; k < this.NoOfColumns; k++)
{
this.LoadedMatrix[j][k] -= this.LoadedMatrix[j][i] * this.LoadedMatrix[i][k];
}
}
}
return(identityMatrixP);
}
/// <summary>
/// Subtracts two matrices.
/// </summary>
/// <param name="matrix">A matrix being subtracted from another matrix.</param>
/// <returns>Result of subtraction of matrices.</returns>
public Matrica SubtractMatrices(Matrica matrix)
{
Matrica result = new Matrica();
if (this.NoOfRows != matrix.NoOfRows || this.NoOfColumns != matrix.NoOfColumns)
{
throw new ArgumentException("Matrices you want to subtract do not have compatible dimensions for this operation!");
}
result.NoOfRows = this.NoOfRows;
result.NoOfColumns = this.NoOfColumns;
for (int i = 0; i < this.NoOfRows; i++)
{
List <double> row = new List <double>();
for (int j = 0; j < this.NoOfColumns; j++)
{
row.Insert(j, this.LoadedMatrix[i][j] - matrix.LoadedMatrix[i][j]);
}
result.LoadedMatrix.Add(i, row);
}
return(result);
}
/// <summary>
/// Subtracts two matrices.
/// </summary>
/// <param name="matrix">A matrix being subtracted from another matrix.</param>
/// <returns>Result of subtraction of matrices.</returns>
public Matrica SubtractMatrices(Matrica matrix)
{
Matrica result = new Matrica();
if (this.NoOfRows != matrix.NoOfRows || this.NoOfColumns != matrix.NoOfColumns)
{
throw new ArgumentException("Matrice koje želite oduzeti nisu odgovarajućih dimenzija za ovu operaciju!");
}
result.NoOfRows = this.NoOfRows;
result.NoOfColumns = this.NoOfColumns;
for (int i = 0; i < this.NoOfRows; i++)
{
List <double> row = new List <double>();
for (int j = 0; j < this.NoOfColumns; j++)
{
row.Insert(j, this.LoadedMatrix[i][j] - matrix.LoadedMatrix[i][j]);
}
result.LoadedMatrix.Add(i, row);
}
return(result);
}
/// <summary>
/// Solves system of linear equations using LU/LUP decomposition, forward and backward substitution.
/// </summary>
/// <param name="A">Values on the left side of system of linear equations which are multiplied by unknown vector x.</param>
/// <param name="b">Vector containing values from the right side of system of linear equations.</param>
/// <param name="epsilon">Constant used for checking if we are dividing value by zero.</param>
/// <returns>Vector x (result of solving system of linear equations).</returns>
public static Matrica SolveSystemOfLinearEquations(Matrica A, Matrica b, double epsilon)
{
Console.WriteLine("Matrica A:");
Console.WriteLine("============");
A.WriteMatrixInConsole();
Console.WriteLine();
Console.WriteLine("Vektor b:");
Console.WriteLine("===========");
b.WriteMatrixInConsole();
Console.WriteLine();
Matrica copyOfA = new Matrica();
copyOfA.Equals(A);
Matrica copyOfb = new Matrica();
copyOfb.Equals(b);
try
{
A.LUDecomposition(epsilon);
Console.WriteLine("Matrica L:");
Console.WriteLine("============");
Matrica L = A.GetLMatrixFromLU();
L.WriteMatrixInConsole();
Console.WriteLine();
Console.WriteLine("Matrica U:");
Console.WriteLine("============");
Matrica U = A.GetUMatrixFromLU();
U.WriteMatrixInConsole();
Console.WriteLine();
Matrica y = ForwardSubstitution(A, b);
Console.WriteLine("Vektor y:");
Console.WriteLine("===========");
y.WriteMatrixInConsole();
Console.WriteLine();
Matrica x = BackwardSubstitution(A, y, epsilon);
Console.WriteLine("Vektor x:");
Console.WriteLine("===========");
x.WriteMatrixInConsole();
Console.WriteLine();
return(x);
}
catch (DivideByZeroException)
{
Console.WriteLine("Nije moguće riješiti ovaj sustav LU dekompozicijom. Izvođenje LUP dekompozicije...");
A = copyOfA;
b = copyOfb;
Matrica P = A.LUPDecomposition(epsilon, b);
Console.WriteLine("Matrica P:");
Console.WriteLine("============");
P.WriteMatrixInConsole();
Console.WriteLine();
Console.WriteLine("Matrica L:");
Console.WriteLine("============");
Matrica L = A.GetLMatrixFromLU();
L.WriteMatrixInConsole();
Console.WriteLine();
Console.WriteLine("Matrica U:");
Console.WriteLine("============");
Matrica U = A.GetUMatrixFromLU();
U.WriteMatrixInConsole();
Console.WriteLine();
Matrica y = ForwardSubstitution(A, b);
Console.WriteLine("Vektor y:");
Console.WriteLine("===========");
y.WriteMatrixInConsole();
Console.WriteLine();
Matrica x = BackwardSubstitution(A, y, epsilon);
Console.WriteLine("Vektor x:");
Console.WriteLine("===========");
x.WriteMatrixInConsole();
Console.WriteLine();
return(x);
}
}
/// <summary>
/// Solves system of linear equations using LU/LUP decomposition, forward and backward substitution.
/// </summary>
/// <param name="A">Values on the left side of system of linear equations which are multiplied by unknown vector x.</param>
/// <param name="b">Vector containing values from the right side of system of linear equations.</param>
/// <param name="epsilon">Constant used for checking if we are dividing value by zero.</param>
/// <returns>Vector x (result of solving system of linear equations).</returns>
public static Matrica SolveSystemOfLinearEquations(Matrica A, Matrica b, double epsilon)
{
Console.WriteLine("Matrix A:");
Console.WriteLine("============");
A.WriteMatrixInConsole();
Console.WriteLine();
Console.WriteLine("Vector b:");
Console.WriteLine("===========");
b.WriteMatrixInConsole();
Console.WriteLine();
Matrica copyOfA = new Matrica();
copyOfA.Equals(A);
Matrica copyOfb = new Matrica();
copyOfb.Equals(b);
try
{
A.LUDecomposition(epsilon);
Console.WriteLine("Matrix L:");
Console.WriteLine("============");
Matrica L = A.GetLMatrixFromLU();
L.WriteMatrixInConsole();
Console.WriteLine();
Console.WriteLine("Matrix U:");
Console.WriteLine("============");
Matrica U = A.GetUMatrixFromLU();
U.WriteMatrixInConsole();
Console.WriteLine();
Matrica y = ForwardSubstitution(A, b);
Console.WriteLine("Vector y:");
Console.WriteLine("===========");
y.WriteMatrixInConsole();
Console.WriteLine();
Matrica x = BackwardSubstitution(A, y, epsilon);
Console.WriteLine("Vector x:");
Console.WriteLine("===========");
x.WriteMatrixInConsole();
Console.WriteLine();
return(x);
}
catch (DivideByZeroException)
{
Console.WriteLine("It is not possible to solve this system using LU decomposition. Executing LUP decomposition...");
A = copyOfA;
b = copyOfb;
Matrica P = A.LUPDecomposition(epsilon, b);
Console.WriteLine("Matrix P:");
Console.WriteLine("============");
P.WriteMatrixInConsole();
Console.WriteLine();
Console.WriteLine("Matrix L:");
Console.WriteLine("============");
Matrica L = A.GetLMatrixFromLU();
L.WriteMatrixInConsole();
Console.WriteLine();
Console.WriteLine("Matrix U:");
Console.WriteLine("============");
Matrica U = A.GetUMatrixFromLU();
U.WriteMatrixInConsole();
Console.WriteLine();
Matrica y = ForwardSubstitution(A, b);
Console.WriteLine("Vector y:");
Console.WriteLine("===========");
y.WriteMatrixInConsole();
Console.WriteLine();
Matrica x = BackwardSubstitution(A, y, epsilon);
Console.WriteLine("Vector x:");
Console.WriteLine("===========");
x.WriteMatrixInConsole();
Console.WriteLine();
return(x);
}
}