java.lang.Object
- org.bouncycastle.pqc.math.linearalgebra.Matrix
- - org.bouncycastle.pqc.math.linearalgebra.GF2Matrix

```
public class GF2Matrix
extends Matrix
```
This class describes some operations with matrices over finite field GF(2) and is used in ecc and MQ-PKC (also has some specific methods and implementation)

Field Summary
- Fields inherited from class org.bouncycastle.pqc.math.linearalgebra.Matrix
  MATRIX_TYPE_RANDOM_LT, MATRIX_TYPE_RANDOM_REGULAR, MATRIX_TYPE_RANDOM_UT, MATRIX_TYPE_UNIT, MATRIX_TYPE_ZERO, numColumns, numRows

Constructor Summary

Constructors
Constructor	Description
`GF2Matrix(byte[] enc)`	Create the matrix from encoded form.
`GF2Matrix(int n, char typeOfMatrix)`	Create an nxn matrix of the given type.
`GF2Matrix(int n, char typeOfMatrix, java.security.SecureRandom sr)`	Create an nxn matrix of the given type.
`GF2Matrix(int numColumns, int[][] matrix)`	Create the matrix with the contents of the given array.
`GF2Matrix(GF2Matrix a)`	Copy constructor.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`Matrix`	`computeInverse()`	Compute the inverse of this matrix.
`Matrix`	`computeTranspose()`	Compute the transpose of this matrix.
`static GF2Matrix[]`	`createRandomRegularMatrixAndItsInverse(int n, java.security.SecureRandom sr)`	Create a nxn random regular matrix and its inverse.
`boolean`	`equals(java.lang.Object other)`	Compare this matrix with another object.
`GF2Matrix`	`extendLeftCompactForm()`	Compute the full form matrix `(this \| Id)` from this matrix in left compact form, where `Id` is the `k x k` identity matrix and `k` is the number of rows of this matrix.
`GF2Matrix`	`extendRightCompactForm()`	Compute the full form matrix `(Id \| this)` from this matrix in right compact form, where `Id` is the `k x k` identity matrix and `k` is the number of rows of this matrix.
`byte[]`	`getEncoded()`	Returns encoded matrix, i.e., this matrix in byte array form
`double`	`getHammingWeight()`	Returns the percentage of the number of "ones" in this matrix.
`int[][]`	`getIntArray()`
`GF2Matrix`	`getLeftSubMatrix()`	Get the quadratic submatrix of this matrix consisting of the leftmost `numRows` columns.
`int`	`getLength()`
`GF2Matrix`	`getRightSubMatrix()`	Get the submatrix of this matrix consisting of the rightmost `numColumns-numRows` columns.
`int[]`	`getRow(int index)`	Return the row of this matrix with the given index.
`int`	`hashCode()`
`boolean`	`isZero()`	Check if this is the zero matrix (i.e., all entries are zero).
`Matrix`	`leftMultiply(Permutation p)`	Compute the product of a permutation matrix (which is generated from an n-permutation) and this matrix.
`Vector`	`leftMultiply(Vector vec)`	compute product a row vector and this matrix
`Vector`	`leftMultiplyLeftCompactForm(Vector vec)`	Compute the product of the matrix `(this \| Id)` and a column vector, where `Id` is a `(numRows x numRows)` unit matrix.
`Matrix`	`rightMultiply(Matrix mat)`	Compute the product of this matrix and a matrix A over GF(2).
`Matrix`	`rightMultiply(Permutation p)`	Compute the product of this matrix and a permutation matrix which is generated from an n-permutation.
`Vector`	`rightMultiply(Vector vec)`	Compute the product of this matrix and the given column vector.
`Vector`	`rightMultiplyRightCompactForm(Vector vec)`	Compute the product of the matrix `(Id \| this)` and a column vector, where `Id` is a `(numRows x numRows)` unit matrix.
`java.lang.String`	`toString()`

Methods inherited from class org.bouncycastle.pqc.math.linearalgebra.Matrix
getNumColumns, getNumRows

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - GF2Matrix
```
public GF2Matrix(byte[] enc)
```
    Create the matrix from encoded form.
    
    Parameters:
    
    enc - the encoded matrix
  - GF2Matrix
```
public GF2Matrix(int numColumns,
                 int[][] matrix)
```
    Create the matrix with the contents of the given array. The matrix is not copied. Unused coefficients are masked out.
    
    Parameters:
    
    numColumns - the number of columns
    
    matrix - the element array
  - GF2Matrix
```
public GF2Matrix(int n,
                 char typeOfMatrix)
```
    Create an nxn matrix of the given type.
    
    Parameters:
    
    n - the number of rows (and columns)
    
    typeOfMatrix - the martix type (see Matrix for predefined constants)
  - GF2Matrix
```
public GF2Matrix(int n,
                 char typeOfMatrix,
                 java.security.SecureRandom sr)
```
    Create an nxn matrix of the given type.
    
    Parameters:
    
    n - the matrix size
    
    typeOfMatrix - the matrix type
    
    sr - the source of randomness
  - GF2Matrix
```
public GF2Matrix(GF2Matrix a)
```
    Copy constructor.
    
    Parameters:
    
    a - another GF2Matrix
- Method Detail
  - createRandomRegularMatrixAndItsInverse
```
public static GF2Matrix[] createRandomRegularMatrixAndItsInverse(int n,
                                                                 java.security.SecureRandom sr)
```
    Create a nxn random regular matrix and its inverse.
    
    Parameters:
    
    n - number of rows (and columns)
    
    sr - source of randomness
    
    Returns:
    
    the created random regular matrix and its inverse
  - getIntArray
```
public int[][] getIntArray()
```
    Returns:
    
    the array keeping the matrix elements
  - getLength
```
public int getLength()
```
    Returns:
    
    the length of each array representing a row of this matrix
  - getRow
```
public int[] getRow(int index)
```
    Return the row of this matrix with the given index.
    
    Parameters:
    
    index - the index
    
    Returns:
    
    the row of this matrix with the given index
  - getEncoded
```
public byte[] getEncoded()
```
    Returns encoded matrix, i.e., this matrix in byte array form
    
    Specified by:
    
    getEncoded in class Matrix
    
    Returns:
    
    the encoded matrix
  - getHammingWeight
```
public double getHammingWeight()
```
    Returns the percentage of the number of "ones" in this matrix.
    
    Returns:
    
    the Hamming weight of this matrix (as a ratio).
  - isZero
```
public boolean isZero()
```
    Check if this is the zero matrix (i.e., all entries are zero).
    
    Specified by:
    
    isZero in class Matrix
    
    Returns:
    
    true if this is the zero matrix
  - getLeftSubMatrix
```
public GF2Matrix getLeftSubMatrix()
```
    Get the quadratic submatrix of this matrix consisting of the leftmost numRows columns.
    
    Returns:
    
    the (numRows x numRows) submatrix
  - extendLeftCompactForm
```
public GF2Matrix extendLeftCompactForm()
```
    Compute the full form matrix (this | Id) from this matrix in left compact form, where Id is the k x k identity matrix and k is the number of rows of this matrix.
    
    Returns:
    
    (this | Id)
  - getRightSubMatrix
```
public GF2Matrix getRightSubMatrix()
```
    Get the submatrix of this matrix consisting of the rightmost numColumns-numRows columns.
    
    Returns:
    
    the (numRows x (numColumns-numRows)) submatrix
  - extendRightCompactForm
```
public GF2Matrix extendRightCompactForm()
```
    Compute the full form matrix (Id | this) from this matrix in right compact form, where Id is the k x k identity matrix and k is the number of rows of this matrix.
    
    Returns:
    
    (Id | this)
  - computeTranspose
```
public Matrix computeTranspose()
```
    Compute the transpose of this matrix.
    
    Returns:
    
    (this)^T
  - computeInverse
```
public Matrix computeInverse()
```
    Compute the inverse of this matrix.
    
    Specified by:
    
    computeInverse in class Matrix
    
    Returns:
    
    the inverse of this matrix (newly created).
    
    Throws:
    
    java.lang.ArithmeticException - if this matrix is not invertible.
  - leftMultiply
```
public Matrix leftMultiply(Permutation p)
```
    Compute the product of a permutation matrix (which is generated from an n-permutation) and this matrix.
    
    Parameters:
    
    p - the permutation
    
    Returns:
    
    GF2Matrix P*this
  - leftMultiply
```
public Vector leftMultiply(Vector vec)
```
    compute product a row vector and this matrix
    
    Specified by:
    
    leftMultiply in class Matrix
    
    Parameters:
    
    vec - a vector over GF(2)
    
    Returns:
    
    Vector product a*matrix
  - leftMultiplyLeftCompactForm
```
public Vector leftMultiplyLeftCompactForm(Vector vec)
```
    Compute the product of the matrix (this | Id) and a column vector, where Id is a (numRows x numRows) unit matrix.
    
    Parameters:
    
    vec - the vector over GF(2)
    
    Returns:
    
    (this | Id)*vector
  - rightMultiply
```
public Matrix rightMultiply(Matrix mat)
```
    Compute the product of this matrix and a matrix A over GF(2).
    
    Specified by:
    
    rightMultiply in class Matrix
    
    Parameters:
    
    mat - a matrix A over GF(2)
    
    Returns:
    
    matrix product this*matrixA
  - rightMultiply
```
public Matrix rightMultiply(Permutation p)
```
    Compute the product of this matrix and a permutation matrix which is generated from an n-permutation.
    
    Specified by:
    
    rightMultiply in class Matrix
    
    Parameters:
    
    p - the permutation
    
    Returns:
    
    GF2Matrix this*P
  - rightMultiply
```
public Vector rightMultiply(Vector vec)
```
    Compute the product of this matrix and the given column vector.
    
    Specified by:
    
    rightMultiply in class Matrix
    
    Parameters:
    
    vec - the vector over GF(2)
    
    Returns:
    
    this*vector
  - rightMultiplyRightCompactForm
```
public Vector rightMultiplyRightCompactForm(Vector vec)
```
    Compute the product of the matrix (Id | this) and a column vector, where Id is a (numRows x numRows) unit matrix.
    
    Parameters:
    
    vec - the vector over GF(2)
    
    Returns:
    
    (Id | this)*vector
  - equals
```
public boolean equals(java.lang.Object other)
```
    Compare this matrix with another object.
    
    Overrides:
    
    equals in class java.lang.Object
    
    Parameters:
    
    other - another object
    
    Returns:
    
    the result of the comparison
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class java.lang.Object
    
    Returns:
    
    the hash code of this matrix
  - toString
```
public java.lang.String toString()
```
    Specified by:
    
    toString in class Matrix
    
    Returns:
    
    a human readable form of the matrix

Class GF2Matrix

Field Summary

Fields inherited from class org.bouncycastle.pqc.math.linearalgebra.Matrix

Constructor Summary

Method Summary

Methods inherited from class org.bouncycastle.pqc.math.linearalgebra.Matrix

Methods inherited from class java.lang.Object

Constructor Detail

GF2Matrix

GF2Matrix

GF2Matrix

GF2Matrix

GF2Matrix

Method Detail

createRandomRegularMatrixAndItsInverse

getIntArray

getLength

getRow

getEncoded

getHammingWeight

isZero

getLeftSubMatrix

extendLeftCompactForm

getRightSubMatrix

extendRightCompactForm

computeTranspose

computeInverse

leftMultiply

leftMultiply

leftMultiplyLeftCompactForm

rightMultiply

rightMultiply

rightMultiply

rightMultiplyRightCompactForm

equals

hashCode

toString