Package com.irurueta.algebra

Class Matrix

java.lang.Object
com.irurueta.algebra.Matrix
All Implemented Interfaces:
Serializable, Cloneable
public class Matrix extends Object implements Serializable, Cloneable
Defines a matrix of numerical data. Values of a matrix are stored inside an internal array of data.
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private double[]
    buffer
    Array containing data of matrix.
    private int[]
    columnIndex
    Array used for indexing column start positions within buffer.
    private int
    columns
    Number of matrix columns.
    static final boolean
    DEFAULT_USE_COLUMN_ORDER
    Constant defining the default order in which values are stored in a matrix.
    private int
    rows
    Number of matrix rows.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Matrix(int rows, int columns)
    Constructor of this class.
    Matrix(Matrix m)
    Copy constructor.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    add(Matrix other)
    Adds provided matrix to this instance.
    void
    add(Matrix other, Matrix result)
    Adds another matrix to this matrix instance and stores the result in provided result matrix.
    Matrix
    addAndReturnNew(Matrix other)
    Adds provided matrix to this instance and returns the result as a new matrix instance.
    Matrix
    clone()
    Returns a new matrix instance containing the same data as this instance.
    void
    copyFrom(Matrix input)
    Copies the contents of provided matrix into this instance.
    void
    copyTo(Matrix output)
    Copies this matrix data into provided matrix.
    static Matrix
    createWithGaussianRandomValues(int rows, int columns, double mean, double standardDeviation)
    Creates new matrix instance using provided size and containing gaussian/normal distributed random values with provided median and standard deviation.
    static Matrix
    createWithGaussianRandomValues(int rows, int columns, double mean, double standardDeviation, Random random)
    Creates new matrix instance using provided size and containing gaussian/normal distributed random values with provided median and standard deviation and using provided random generator
    static Matrix
    createWithUniformRandomValues(int rows, int columns, double minValue, double maxValue)
    Creates new matrix instance using provided size and containing uniformly distributed random values with provided range.
    static Matrix
    createWithUniformRandomValues(int rows, int columns, double minValue, double maxValue, Random random)
    Creates new matrix instance using provided size and containing uniformly distributed random values with provided range and using provided random generator
    static Matrix
    diagonal(double[] diagonal)
    Creates a diagonal matrix having all the elements in provided array in its diagonal and the remaining elements equal to zero.
    static void
    diagonal(double[] diagonal, Matrix result)
    Makes provided result matrix a diagonal matrix containing provided elements in the diagonal.
    void
    elementByElementProduct(Matrix other)
    Computes element by element product (i.e.
    void
    elementByElementProduct(Matrix other, Matrix result)
    Computes element by element product (i.e.
    Matrix
    elementByElementProductAndReturnNew(Matrix other)
    Computes element by element product (i.e.
    boolean
    equals(Matrix other)
    Checks if provided matrix has exactly the same contents as this matrix instance.
    boolean
    equals(Matrix other, double threshold)
    Checks if provided matrix has contents similar to this matrix by checking that all values have a maximum difference equal to provided threshold and same size.
    boolean
    equals(Object obj)
    Checks if provided object is a Matrix instance having exactly the same contents as this matrix instance.
    static void
    fillWithGaussianRandomValues(double mean, double standardDeviation, Matrix result)
    Fills provided matrix with random Gaussian values with provided mean and standard deviation
    static void
    fillWithGaussianRandomValues(double mean, double standardDeviation, Random random, Matrix result)
    Fills provided matrix with random Gaussian values with provided mean and standard deviation.
    static void
    fillWithUniformRandomValues(double minValue, double maxValue, Matrix result)
    Fills provided matrix with random uniform values ranging from minValue to maxValue.
    static void
    fillWithUniformRandomValues(double minValue, double maxValue, Random random, Matrix result)
    Fills provided matrix with random uniform values ranging from minValue to maxValue.
    void
    fromArray(double[] array)
    Copies elements of array into this instance using column order.
    void
    fromArray(double[] array, boolean isColumnOrder)
    Copies elements of array into this instance using provided order.
    double[]
    getBuffer()
    Returns current matrix internal buffer of data.
    int
    getColumns()
    Returns number of columns in matrix.
    double
    getElementAt(int row, int column)
    Obtains element in matrix located at position (row and column).
    double
    getElementAtIndex(int index)
    Obtains element in matrix located at provided index value using the order specified by DEFAULT_USE_COLUMN_ORDER.
    double
    getElementAtIndex(int index, boolean isColumnOrder)
    Obtain element in matrix located at provided index value using provided order (either column or row order).
    int
    getIndex(int row, int column)
    Returns index within internal buffer corresponding to provided row and column positions.
    int
    getRows()
    Returns number of rows in matrix.
    Matrix
    getSubmatrix(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn)
    Obtains a sub-matrix of current matrix instance.
    void
    getSubmatrix(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, Matrix result)
    Obtains a sub-matrix of current matrix instance.
    double[]
    getSubmatrixAsArray(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn)
    Obtains sub-matrix of current matrix instance as an array of values using DEFAULT_USE_COLUMN_ORDER.
    double[]
    getSubmatrixAsArray(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, boolean isColumnOrder)
    Obtains sub-matrix of current matrix instance as an array of values using provided order.
    void
    getSubmatrixAsArray(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, boolean isColumnOrder, double[] array)
    Retrieves a sub-matrix of current matrix instance as an array of values using provided column order and storing the result in provided array.
    void
    getSubmatrixAsArray(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, double[] array)
    Retrieves a sub-matrix of current matrix instance as an array of values using column order and storing the result in provided array.
    int
    hashCode()
    Computes and returns hash code for this instance.
    static Matrix
    identity(int rows, int columns)
    Creates and returns a new matrix instance having all the elements on the diagonal equal to one and the remaining ones equal to zero.
    static void
    identity(Matrix m)
    Sets values into provided matrix to make it an identity matrix (all elements in the diagonal equal to one, and remaining elements to zero).
    void
    initialize(double initValue)
    Sets the contents of this matrix to provided value in all of its elements
    private void
    internalAdd(Matrix other, Matrix result)
    Method to internally add two matrices.
    private void
    internalElementByElementProduct(Matrix other, Matrix result)
    Method to internally compute element by element product of two matrices.
    private void
    internalGetSubmatrix(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, Matrix result)
    Internal method to retrieve a sub-matrix of current matrix instance.
    private void
    internalGetSubmatrixAsArray(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, boolean isColumnOrder, double[] result)
    Internal method to retrieve a sub-matrix of current matrix instance as an array of values using provided column order and storing the result in provided array.
    private void
    internalMultiply(Matrix other, double[] resultBuffer, int[] resultColumnIndex)
    Method to internally multiply two matrices.
    private void
    internalMultiply(Matrix other, Matrix result)
    Method to internally multiply two matrices.
    private void
    internalMultiplyKronecker(Matrix other, double[] resultBuffer, int[] resultColumnIndex)
    Method to internally compute the Kronecker product between two matrices.
    private void
    internalMultiplyKronecker(Matrix other, Matrix result)
    Method to internally compute the Kronecker product between two matrices.
    private void
    internalResize(int rows, int columns)
    Method used internally to remove matrix contents and resizing it.
    private void
    internalSubtract(Matrix other, Matrix result)
    Method to internally subtract two matrices.
    private void
    internalTranspose(double[] resultBuffer, int[] resultColumnIndex)
    Method to internally compute matrix transposition.
    private void
    internalTranspose(Matrix result)
    Method to internally compute matrix transposition.
    void
    multiply(Matrix other)
    Multiplies this matrix with provided matrix.
    void
    multiply(Matrix other, Matrix result)
    Multiplies another matrix to this matrix instance and stores the result in provided result matrix.
    Matrix
    multiplyAndReturnNew(Matrix other)
    Multiplies this matrix with provided matrix and returns the result as a new instance.
    void
    multiplyByScalar(double scalar)
    Computes product by scalar of this instance multiplying all its elements by provided scalar value and returning the result as a new instance.
    private void
    multiplyByScalar(double scalar, Matrix result)
    Computes product by scalar of this instance multiplying all its elements by provided scalar value and storing the results in provided result matrix.
    Matrix
    multiplyByScalarAndReturnNew(double scalar)
    Computes product by scalar of this instance multiplying all its elements by provided scalar value and returning the result as a new instance.
    void
    multiplyKronecker(Matrix other)
    Computes the Kronecker product of this matrix with provided matrix and updates this matrix with the result of the multiplication.
    void
    multiplyKronecker(Matrix other, Matrix result)
    Computes the Kronecker product with provided matrix and stores the result in provided result matrix.
    Matrix
    multiplyKroneckerAndReturnNew(Matrix other)
    Computes the Kronecker product with provided matrix and returns the result as a new instance.
    static Matrix
    newFromArray(double[] array)
    Instantiates new matrix from array using DEFAULT_USE_COLUMN_ORDER
    static Matrix
    newFromArray(double[] array, boolean isColumnOrder)
    Instantiates new matrix from array using either column or row order
    void
    reset(int rows, int columns, double initValue)
    Resets current instance by removing its contents, resizing it to provided size and setting all its elements to provided value.
    void
    resize(int rows, int columns)
    Resizes current instance by removing its contents and resizing it to provided size.
    void
    setElementAt(int row, int column, double value)
    Sets element in matrix located at provided position (row and column).
    void
    setElementAtIndex(int index, double value)
    Sets element in matrix located at provided index using the order specified by DEFAULT_USE_COLUMN_ORDER.
    void
    setElementAtIndex(int index, double value, boolean isColumnOrder)
    Sets element in matrix located at provided index using provided order (either column or row order).
    void
    setSubmatrix(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, double value)
    Sets elements in provided region to provided value.
    void
    setSubmatrix(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, double[] values)
    Copies elements from provided array into this matrix at provided location.
    void
    setSubmatrix(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, double[] values, boolean isColumnOrder)
    Copies elements from provided array into this matrix at provided location.
    void
    setSubmatrix(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, double[] values, int valuesStart, int valuesEnd)
    Copies elements from provided array into this matrix at provided location.
    void
    setSubmatrix(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, double[] values, int valuesStart, int valuesEnd, boolean isColumnOrder)
    Copies elements from provided array into this matrix at provided location.
    void
    setSubmatrix(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, Matrix submatrix)
    Copies elements from provided sub-matrix into this matrix at provided location.
    void
    setSubmatrix(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, Matrix submatrix, int submatrixTopLeftRow, int submatrixTopLeftColumn, int submatrixBottomRightRow, int submatrixBottomRightColumn)
    Copies elements from provided sub-matrix into this matrix at provided location
    void
    subtract(Matrix other)
    Subtracts provided matrix from this instance.
    void
    subtract(Matrix other, Matrix result)
    Subtracts another matrix from this matrix instance and stores the result in provided result matrix.
    Matrix
    subtractAndReturnNew(Matrix other)
    Subtracts provided matrix from this instance and returns the result as a new matrix instance.
    void
    symmetrize()
    Symmetrizes this instance and updates it with computed value.
    void
    symmetrize(Matrix result)
    Symmetrizes this instance and stores the result into provided instance.
    Matrix
    symmetrizeAndReturnNew()
    Symmetrizes this instance and returns the result as a new matrix instance.
    double[]
    toArray()
    Returns the contents of the matrix as an array of values using DEFAULT_USE_COLUMN_ORDER to pick elements.
    double[]
    toArray(boolean isColumnOrder)
    Returns the contents of the matrix as an array of values using provided order to pick elements.
    void
    toArray(double[] result)
    Copies the contents of the matrix to an array of values using column order.
    void
    toArray(double[] result, boolean isColumnOrder)
    Copies the contents of the matrix to an array of values using provided order to pick elements.
    void
    transpose()
    Transposes current matrix.
    void
    transpose(Matrix result)
    Transposes current matrix and stores result in provided matrix.
    Matrix
    transposeAndReturnNew()
    Transposes current matrix and returns result as a new instance.

    Methods inherited from class java.lang.Object

    finalize, getClass, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • DEFAULT_USE_COLUMN_ORDER

      public static final boolean DEFAULT_USE_COLUMN_ORDER
      Constant defining the default order in which values are stored in a matrix. This can be useful when copying data to and from an array.
      See Also:

    • rows

      private int rows
      Number of matrix rows.

    • columns

      private int columns
      Number of matrix columns.

    • buffer

      private double[] buffer
      Array containing data of matrix. Data is stored linearly in memory using column order.

    • columnIndex

      private int[] columnIndex
      Array used for indexing column start positions within buffer. This is used for faster access to matrix elements.

  • Constructor Details

    • Matrix

      public Matrix(int rows, int columns) throws WrongSizeException
      Constructor of this class. By default, when instantiating a matrix its values are undefined.
      Parameters:
      rows - Defines number of rows in matrix.
      columns - Defines number of columns in matrix.
      Throws:
      WrongSizeException - Exception thrown if matrix must be empty with provided size. In other words, matrices must have at least one row and one column. Leaving number of rows or columns to zero will raise this exception.

    • Matrix

      public Matrix(Matrix m)
      Copy constructor.
      Parameters:
      m - matrix to copy from.

  • Method Details

    • getRows

      public int getRows()
      Returns number of rows in matrix.
      Returns:
      Number of rows in matrix.

    • getColumns

      public int getColumns()
      Returns number of columns in matrix.
      Returns:
      Number of columns in matrix.

    • getElementAt

      public double getElementAt(int row, int column)
      Obtains element in matrix located at position (row and column). Notice that row and column position are zero-indexed.
      Parameters:
      row - Row to be used for element location.
      column - Column to be used for element location.
      Returns:
      Value of element in matrix located at provided position.
      Throws:
      ArrayIndexOutOfBoundsException - Exception raised if attempting to access a location that lies outside the boundaries of the internal array containing matrix data. Notice that internal data is stored in column order, hence, if row position exceeds the number of rows in the matrix, this exception might not be raised depending on column position, however, if the column value exceeds the number of columns, it will always raise the exception.

    • getIndex

      public int getIndex(int row, int column)
      Returns index within internal buffer corresponding to provided row and column positions.
      Parameters:
      row - row to be used for element location.
      column - column to be used for element location.
      Returns:
      index within internal buffer.

    • getElementAtIndex

      public double getElementAtIndex(int index)
      Obtains element in matrix located at provided index value using the order specified by DEFAULT_USE_COLUMN_ORDER. Note: an index indicates linear position within matrix, in layman terms, if using column order, then position (i, j), where i stands for row index and j for column index, becomes index = j * rows + 1. On the other hand, if using row order then index becomes index = i * columns + j.
      Parameters:
      index - Linear position.
      Returns:
      Value of element contained at provided position.
      Throws:
      ArrayIndexOutOfBoundsException - Exception raised if index lays outside valid values, which range from zero (inclusive) to rows * columns (exclusive)

    • getElementAtIndex

      public double getElementAtIndex(int index, boolean isColumnOrder)
      Obtain element in matrix located at provided index value using provided order (either column or row order).
      Parameters:
      index - Linear position.
      isColumnOrder - if true indicates that values are retrieved assuming that are stored in column order.
      Returns:
      Value of element contained at provided position.
      Throws:
      ArrayIndexOutOfBoundsException - Exception raised if index lays outside valid values, which range from zero (inclusive) to rows * columns (exclusive)

    • setElementAt

      public void setElementAt(int row, int column, double value)
      Sets element in matrix located at provided position (row and column).
      Parameters:
      row - Row to be used for element location to be set.
      column - Column to be used for element location to be set.
      value - Value to be set at provided position.
      Throws:
      ArrayIndexOutOfBoundsException - Exception raised if attempting to access a location that lies outside the boundaries of the internal array containing matrix data. Notice that internal data is stored in column order, hence, if row position exceeds the number of rows in the matrix, this exception might not be raised depending on column position, however, if the column value exceeds the number of columns, it will always raise the exception.

    • setElementAtIndex

      public void setElementAtIndex(int index, double value)
      Sets element in matrix located at provided index using the order specified by DEFAULT_USE_COLUMN_ORDER. Note: an index indicates linear position within matrix, in layman terms, if using column order, then position (i, j), where i stands for row index and j for column index, becomes index = j * rows + 1. On the other hand, if using row order then index becomes index = i * columns + j.
      Parameters:
      index - Linear position.
      value - Value of element contained at provided position.
      Throws:
      ArrayIndexOutOfBoundsException - Exception raised if index lays outside valid values, which range from zero (inclusive) to rows * columns (exclusive)

    • setElementAtIndex

      public void setElementAtIndex(int index, double value, boolean isColumnOrder)
      Sets element in matrix located at provided index using provided order (either column or row order).
      Parameters:
      index - Linear position.
      value - Value of element to be set at provided position.
      isColumnOrder - if true indicates that values are retrieved assuming that are stored in column order.
      Throws:
      ArrayIndexOutOfBoundsException - Exception raised if index lays outside valid values, which range from zero (inclusive) to rows * columns (exclusive).

    • clone

      public Matrix clone() throws CloneNotSupportedException
      Returns a new matrix instance containing the same data as this instance.
      Overrides:
      clone in class Object
      Returns:
      A copy of this matrix instance.
      Throws:
      CloneNotSupportedException - if clone fails.

    • copyTo

      public void copyTo(Matrix output)
      Copies this matrix data into provided matrix. Provided output matrix will be resized if needed.
      Parameters:
      output - Destination matrix where data will be copied to.
      Throws:
      NullPointerException - Exception raised if provided output matrix is null.

    • copyFrom

      public void copyFrom(Matrix input)
      Copies the contents of provided matrix into this instance. This instance will be resized if needed.
      Parameters:
      input - Input matrix where data will be copied from.
      Throws:
      NullPointerException - Exception raised if provided input matrix is null.

    • add

      public void add(Matrix other, Matrix result) throws WrongSizeException
      Adds another matrix to this matrix instance and stores the result in provided result matrix. If provided result matrix doesn't have proper size, it will be resized.
      Parameters:
      other - Matrix to be added to current instance.
      result - Matrix where result of summation is stored.
      Throws:
      WrongSizeException - Exception thrown if provided matrix to be added (i.e. other) does not have the same size as this matrix.
      NullPointerException - Exception raised if provided matrices are null.

    • addAndReturnNew

      public Matrix addAndReturnNew(Matrix other) throws WrongSizeException
      Adds provided matrix to this instance and returns the result as a new matrix instance.
      Parameters:
      other - Matrix to be added.
      Returns:
      Returns a new matrix containing the sum of this matrix with provided matrix.
      Throws:
      WrongSizeException - Exception raised if provided matrix does not have the same size as this matrix.
      NullPointerException - Exception raised if provided matrix is null.

    • add

      public void add(Matrix other) throws WrongSizeException
      Adds provided matrix to this instance.
      Parameters:
      other - Matrix to be added.
      Throws:
      WrongSizeException - Exception raised if provided matrix does not have the same size as this matrix.
      NullPointerException - Exception raised if provided matrix is null.

    • subtract

      public void subtract(Matrix other, Matrix result) throws WrongSizeException
      Subtracts another matrix from this matrix instance and stores the result in provided result matrix. If provided result matrix doesn't have proper size, it will be resized.
      Parameters:
      other - Matrix to be added to current instance.
      result - Matrix where result of subtraction is stored.
      Throws:
      WrongSizeException - Exception thrown if provided matrix to be subtracted (i.e. other) does not have the same size as this matrix.
      NullPointerException - Exception raised if provided matrices are null.

    • subtractAndReturnNew

      public Matrix subtractAndReturnNew(Matrix other) throws WrongSizeException
      Subtracts provided matrix from this instance and returns the result as a new matrix instance.
      Parameters:
      other - Matrix to be subtracted from.
      Returns:
      Returns a new matrix containing the subtraction of provided matrix from this matrix.
      Throws:
      WrongSizeException - Exception raised if provided matrix does not have the same size as this matrix.
      NullPointerException - Exception raised if provided matrix is null.

    • subtract

      public void subtract(Matrix other) throws WrongSizeException
      Subtracts provided matrix from this instance.
      Parameters:
      other - Matrix to be subtracted from.
      Throws:
      WrongSizeException - Exception raised if provided matrix does not have the same size as this matrix.
      NullPointerException - Exception raised if provided matrix is null.

    • multiply

      public void multiply(Matrix other, Matrix result) throws WrongSizeException
      Multiplies another matrix to this matrix instance and stores the result in provided result matrix. If provided result matrix doesn't have proper size, it will be resized.
      Parameters:
      other - Matrix to be multiplied to current instance.
      result - Matrix where result of product is stored.
      Throws:
      WrongSizeException - Exception thrown when current and provided matrix (i.e. other) has incompatible size for product computation.
      NullPointerException - Exception raised if provided matrices are null.

    • multiplyAndReturnNew

      public Matrix multiplyAndReturnNew(Matrix other) throws WrongSizeException
      Multiplies this matrix with provided matrix and returns the result as a new instance. If this matrix m1 has size m x n and provided matrix m2 has size p x q, then n must be equal to p so that product m1 * m2 can be correctly computed obtaining a matrix of size m x q, otherwise an IllegalArgumentException will be raised.
      Parameters:
      other - Right operand of matrix product
      Returns:
      Matrix containing result of multiplication
      Throws:
      WrongSizeException - Exception thrown when current and provided matrices have incompatible sizes for product computation.
      NullPointerException - Exception thrown if provided matrix is null

    • multiply

      public void multiply(Matrix other) throws WrongSizeException
      Multiplies this matrix with provided matrix. If this matrix m1 has size m x n and provided matrix m2 has size p x q, then n must be equal to p so that product m1 * m2 can be correctly computed resizing this matrix to a new one having size m x q, otherwise an IllegalArgumentException will be raised.
      Parameters:
      other - Right operand of matrix product
      Throws:
      WrongSizeException - Exception thrown when current and provided matrices have incompatible sizes for product computation.
      NullPointerException - Exception thrown if provided matrix is null

    • multiplyKronecker

      public void multiplyKronecker(Matrix other, Matrix result)
      Computes the Kronecker product with provided matrix and stores the result in provided result matrix. If provided result matrix doesn't have proper size, it will be resized.
      Parameters:
      other - other matrix to be Kronecker multiplied to current matrix.
      result - matrix where result will be stored.

    • multiplyKroneckerAndReturnNew

      public Matrix multiplyKroneckerAndReturnNew(Matrix other)
      Computes the Kronecker product with provided matrix and returns the result as a new instance. If this matrix m1 has size mxn and provided matrix m2 has size pxq, the resulting matrix will be m*pxn*q.
      Parameters:
      other - other matrix to be Kronecker multiplied to current matrix.
      Returns:
      matrix containing result of Kronecker multiplication.

    • multiplyKronecker

      public void multiplyKronecker(Matrix other)
      Computes the Kronecker product of this matrix with provided matrix and updates this matrix with the result of the multiplication. If this matrix m1 has size mxn and provided matrix m2 has size pxq, the resulting matrix will be resized to m*pxn*q.
      Parameters:
      other - other matrix to be Kronecker multiplied to current matrix.

    • multiplyByScalar

      private void multiplyByScalar(double scalar, Matrix result)
      Computes product by scalar of this instance multiplying all its elements by provided scalar value and storing the results in provided result matrix. If provided result matrix doesn't have proper size, it will be automatically resized.
      Parameters:
      scalar - Scalar amount that current matrix will be multiplied by.
      result - Matrix where result of operation is stored.

    • multiplyByScalarAndReturnNew

      public Matrix multiplyByScalarAndReturnNew(double scalar)
      Computes product by scalar of this instance multiplying all its elements by provided scalar value and returning the result as a new instance.
      Parameters:
      scalar - Scalar amount that current matrix will be multiplied by.
      Returns:
      Returns a new matrix instance that contains result of product by scalar.

    • multiplyByScalar

      public void multiplyByScalar(double scalar)
      Computes product by scalar of this instance multiplying all its elements by provided scalar value and returning the result as a new instance.
      Parameters:
      scalar - Scalar amount that current matrix will be multiplied by.

    • equals

      public boolean equals(Object obj)
      Checks if provided object is a Matrix instance having exactly the same contents as this matrix instance.
      Overrides:
      equals in class Object
      Parameters:
      obj - Object to be compared
      Returns:
      Returns true if both objects are considered to be equal.

    • hashCode

      public int hashCode()
      Computes and returns hash code for this instance. Hash codes are almost unique values that are useful for fast classification and storage of objects in collections.
      Overrides:
      hashCode in class Object
      Returns:
      Hash code

    • equals

      public boolean equals(Matrix other)
      Checks if provided matrix has exactly the same contents as this matrix instance.
      Parameters:
      other - Matrix to be compared.
      Returns:
      Returns true if both objects are considered to be equal (same content and size)

    • equals

      public boolean equals(Matrix other, double threshold)
      Checks if provided matrix has contents similar to this matrix by checking that all values have a maximum difference equal to provided threshold and same size.
      Parameters:
      other - Matrix to be compared
      threshold - Maximum difference allowed between values on same position to determine that matrices are equal
      Returns:
      True if matrices are considered to be equal (almost equal content and same size)

    • elementByElementProduct

      public void elementByElementProduct(Matrix other, Matrix result) throws WrongSizeException
      Computes element by element product (i.e. Hadamard product) between current and provided (i.e. other) matrix, and stores the result in provided result matrix.
      Parameters:
      other - Instance that will be used for element by element product with current instance.
      result - Matrix where result of operation is stored.
      Throws:
      WrongSizeException - Exception raised if attempting to perform element by element product on matrices of different size.
      NullPointerException - Exception raised if provided matrix is null

    • elementByElementProductAndReturnNew

      public Matrix elementByElementProductAndReturnNew(Matrix other) throws WrongSizeException
      Computes element by element product (i.e. Hadamard product) between current and provided instances and returns the result as a new instance. Example: Having matrices [1, 2, 3] [10, 11, 12] m1 = [4, 5, 6] m2 = [13, 14, 15] [7, 8, 9] [16, 17, 18] Then their element by element product will be [10, 22, 36 ] m3 = [52, 70, 90 ] [112, 136, 162]

      Note: Attempting to perform element product on matrices of different size will raise an IllegalArgumentException

      Parameters:
      other - Instance that will be used for element by element product with current instance.
      Returns:
      A new Matrix containing element by element product result
      Throws:
      WrongSizeException - Exception raised if attempting to perform element by element product on matrices of different size.
      NullPointerException - Exception raised if provided matrix is null

    • elementByElementProduct

      public void elementByElementProduct(Matrix other) throws WrongSizeException
      Computes element by element product (i.e. Hadamard product) between current and provided instances. Example: Having matrices [1, 2, 3] [10, 11, 12] m1 = [4, 5, 6] m2 = [13, 14, 15] [7, 8, 9] [16, 17, 18] Then their element by element product will be [10, 22, 36 ] m3 = [52, 70, 90 ] [112, 136, 162]

      Note: Attempting to perform element product on matrices of different size will raise an IllegalArgumentException

      Parameters:
      other - Instance that will be used for element by element product with current instance.
      Throws:
      WrongSizeException - Exception raised if attempting to perform element by element product on matrices of different size.
      NullPointerException - Exception raised if provided matrix is null

    • transpose

      public void transpose(Matrix result)
      Transposes current matrix and stores result in provided matrix. If provided matrix doesn't have proper size, it will be resized.
      Parameters:
      result - Instance where transposed matrix is stored.

    • transposeAndReturnNew

      public Matrix transposeAndReturnNew()
      Transposes current matrix and returns result as a new instance. Transposition of a matrix is done by exchanging rows and columns, in Layman terms, given a matrix m1 with elements located at m1(i,j), where i is the row index and j is the column index, then it follows that its transposed matrix m2 has the following property m2(i,j) = m1(j, i).
      Returns:
      A new Matrix instance containing transposed matrix.

    • transpose

      public void transpose()
      Transposes current matrix. Transposition of a matrix is done by exchanging rows and columns, in Layman terms, given a matrix m1 with elements located at m1(i,j), where i is the row index and j is the column index, then it follows that its transposed matrix m2 has the following property m2(i,j) = m1(j, i).

    • initialize

      public void initialize(double initValue)
      Sets the contents of this matrix to provided value in all of its elements
      Parameters:
      initValue - Value to be set on all the elements of this matrix.

    • resize

      public void resize(int rows, int columns) throws WrongSizeException
      Resizes current instance by removing its contents and resizing it to provided size.
      Parameters:
      rows - Number of rows to be set
      columns - Number of columns to be set
      Throws:
      WrongSizeException - Exception raised if either rows or columns is zero.

    • reset

      public void reset(int rows, int columns, double initValue) throws WrongSizeException
      Resets current instance by removing its contents, resizing it to provided size and setting all its elements to provided value.
      Parameters:
      rows - Number of rows to be set
      columns - Number of columns to be set
      initValue - Value to be set in all of its elements
      Throws:
      WrongSizeException - Exception raised if either rows or columns is zero.

    • toArray

      public double[] toArray()
      Returns the contents of the matrix as an array of values using DEFAULT_USE_COLUMN_ORDER to pick elements.
      Returns:
      Contents of matrix as an array

    • toArray

      public double[] toArray(boolean isColumnOrder)
      Returns the contents of the matrix as an array of values using provided order to pick elements.
      Parameters:
      isColumnOrder - If true, picks elements from matrix using column order, otherwise row order is used.
      Returns:
      Contents of matrix as an array,

    • toArray

      public void toArray(double[] result) throws WrongSizeException
      Copies the contents of the matrix to an array of values using column order.
      Parameters:
      result - array where values will be copied to.
      Throws:
      WrongSizeException - if provided result array does not have the same number of elements as the matrix (i.e. rows x columns).

    • toArray

      public void toArray(double[] result, boolean isColumnOrder) throws WrongSizeException
      Copies the contents of the matrix to an array of values using provided order to pick elements.
      Parameters:
      result - array where values will be copied to.
      isColumnOrder - if true, picks elements from matrix using column order, otherwise row order is used.
      Throws:
      WrongSizeException - if provided result array does not have the same number of elements as the matrix (i.e. rows x columns).

    • getBuffer

      public double[] getBuffer()
      Returns current matrix internal buffer of data.
      Returns:
      Internal buffer of data.

    • getSubmatrix

      public void getSubmatrix(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, Matrix result)
      Obtains a sub-matrix of current matrix instance. Sub-matrix is obtained by copying all elements contained within provided coordinates (both top-left and bottom-right points are included within sub-matrix).
      Parameters:
      topLeftRow - Top-left row index where sub-matrix starts.
      topLeftColumn - Top-left column index where sub-matrix starts.
      bottomRightRow - Bottom-right row index where sub-matrix ends.
      bottomRightColumn - Bottom-right column index where sub-matrix ends.
      result - Instance where sub-matrix data is stored.
      Throws:
      IllegalArgumentException - Exception raised whenever top-left or bottom-right corners lie outside current matrix instance, or if top-left corner is indeed located below or at right side of bottom-right corner.
      NullPointerException - If provided result matrix is null.

    • getSubmatrix

      public Matrix getSubmatrix(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn)
      Obtains a sub-matrix of current matrix instance. Sub-matrix is obtained by copying all elements contained within provided coordinates (both top-left and bottom-right points are included within sub-matrix).
      Parameters:
      topLeftRow - Top-left row index where sub-matrix starts.
      topLeftColumn - Top-left column index where sub-matrix starts.
      bottomRightRow - Bottom-right row index where sub-matrix ends.
      bottomRightColumn - Bottom-right column index where sub-matrix ends.
      Returns:
      A new instance containing selected sub-matrix.
      Throws:
      IllegalArgumentException - Exception raised whenever top-left or bottom-right corners lie outside current matrix instance, or if top-left corner is indeed located belo or at right side of bottom-right corner.

    • getSubmatrixAsArray

      public void getSubmatrixAsArray(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, double[] array) throws WrongSizeException
      Retrieves a sub-matrix of current matrix instance as an array of values using column order and storing the result in provided array. Sub-matrix is obtained by copying all elements contained within provided coordinates (both top-left and bottom-right points are included within sub-matrix).
      Parameters:
      topLeftRow - Top-left row index where sub-matrix starts
      topLeftColumn - Top-left column index where sub-matrix starts
      bottomRightRow - Bottom-right row index where sub-matrix ends
      bottomRightColumn - Bottom-right column index where sub-matrix ends.
      array - Array where sub-matrix data is stored.
      Throws:
      IllegalArgumentException - Thrown if provided coordinates lie outside of matrix boundaries or if top-left corner is at the bottom or right side of bottom-right corner
      WrongSizeException - thrown if length of provided array does not match the number of elements to be extracted from this matrix

    • getSubmatrixAsArray

      public void getSubmatrixAsArray(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, boolean isColumnOrder, double[] array) throws WrongSizeException
      Retrieves a sub-matrix of current matrix instance as an array of values using provided column order and storing the result in provided array. Sub-matrix is obtained by copying all elements contained within provided coordinates (both top-left and bottom-right points are included within sub-matrix).
      Parameters:
      topLeftRow - Top-left row index where sub-matrix starts
      topLeftColumn - Top-left column index where sub-matrix starts
      bottomRightRow - Bottom-right row index where sub-matrix ends
      bottomRightColumn - Bottom-right column index where sub-matrix ends.
      isColumnOrder - If true, picks elements from matrix using column order, otherwise row order is used.
      array - Array where sub-matrix data is stored.
      Throws:
      IllegalArgumentException - Exception raised whenever top-left or bottom-right corners lie outside current matrix instance, or if top-left corner is indeed located below or at right side of bottom-right corner.
      WrongSizeException - If provided array doesn't have proper length, which must be equal to the amount of elements in desired sub-matrix.

    • getSubmatrixAsArray

      public double[] getSubmatrixAsArray(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn)
      Obtains sub-matrix of current matrix instance as an array of values using DEFAULT_USE_COLUMN_ORDER. Array is obtained by copying all elements contained within provided coordinates (both top-left and bottom-right points are included within sub-matrix).
      Parameters:
      topLeftRow - Top-left row index where sub-matrix starts
      topLeftColumn - Top-left column index where sub-matrix starts
      bottomRightRow - Bottom-right row index where sub-matrix ends
      bottomRightColumn - Bottom-right column index where sub-matrix ends.
      Returns:
      An array containing sub-matrix elements
      Throws:
      IllegalArgumentException - Exception raised whenever top-left or bottom-right corners lie outside current matrix instance, or if top-left corner is indeed located belo or at right side of bottom-right corner.

    • getSubmatrixAsArray

      public double[] getSubmatrixAsArray(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, boolean isColumnOrder)
      Obtains sub-matrix of current matrix instance as an array of values using provided order. Array is obtained by copying all elements contained within provided coordinates (both top-left and bottom-right points are included within sub-matrix).
      Parameters:
      topLeftRow - Top-left row index where sub-matrix starts
      topLeftColumn - Top-left column index where sub-matrix starts
      bottomRightRow - Bottom-right row index where sub-matrix ends
      bottomRightColumn - Bottom-right column index where sub-matrix ends.
      isColumnOrder - If true, picks elements from matrix using column order, otherwise row order is used.
      Returns:
      An array containing sub-matrix elements
      Throws:
      IllegalArgumentException - Exception raised whenever top-left or bottom-right corners lie outside current matrix instance, or if top-left corner is indeed located below or at right side of bottom-right corner.

    • setSubmatrix

      public void setSubmatrix(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, Matrix submatrix)
      Copies elements from provided sub-matrix into this matrix at provided location.
      Parameters:
      topLeftRow - Top-left row index where sub-matrix copy starts
      topLeftColumn - Top-left column index where sub-matrix copy starts
      bottomRightRow - Bottom-right row index where sub-matrix copy ends
      bottomRightColumn - Bottom-right column index where sub-matrix copy ends.
      submatrix - Sub-matrix to be copied
      Throws:
      IllegalArgumentException - Exception raised whenever top-left or bottom-right corners lie outside current matrix instance, or if top-left corner is indeed located below or at right side of bottom-right corner.

    • setSubmatrix

      public void setSubmatrix(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, Matrix submatrix, int submatrixTopLeftRow, int submatrixTopLeftColumn, int submatrixBottomRightRow, int submatrixBottomRightColumn)
      Copies elements from provided sub-matrix into this matrix at provided location
      Parameters:
      topLeftRow - Top-left row index where sub-matrix copy starts
      topLeftColumn - Top-left column index where sub-matrix copy starts
      bottomRightRow - Bottom-right row index where sub-matrix copy ends
      bottomRightColumn - Bottom-right column index where sub-matrix copy ends.
      submatrix - Sub-matrix to be copied
      submatrixTopLeftRow - Top-left row index of sub-matrix where copy starts
      submatrixTopLeftColumn - Top-left column index of sub-matrix where copy starts
      submatrixBottomRightRow - Bottom-right row index of sub-matrix where copy ends
      submatrixBottomRightColumn - Bottom-right column index of sub-matrix where copy ends
      Throws:
      IllegalArgumentException - Exception raised whenever top-left or bottom-right corners lie outside current or provided matrices, or if top-left corners are indeed located below or at right side of bottom-right corners.

    • setSubmatrix

      public void setSubmatrix(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, double value)
      Sets elements in provided region to provided value.
      Parameters:
      topLeftRow - Top-left row index of region (inclusive).
      topLeftColumn - Top-left column index of region (inclusive).
      bottomRightRow - Bottom-right row index of region (inclusive).
      bottomRightColumn - Bottom-right column index of region (inclusive).
      value - Value to be set.
      Throws:
      IllegalArgumentException - Exception raised whenever top-left or bottom-right corners lie outside current matrix instance, or if top-left corner is indeed located below or at right side of bottom-right corner.

    • setSubmatrix

      public void setSubmatrix(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, double[] values)
      Copies elements from provided array into this matrix at provided location. Elements in array are copied into this matrix considering DEFAULT_USE_COLUMN_ORDER.
      Parameters:
      topLeftRow - Top-left row index where copy starts.
      topLeftColumn - Top-left column index where copy starts.
      bottomRightRow - Bottom-right row index where copy ends.
      bottomRightColumn - Bottom-right column index where copy ends.
      values - Array to be copied.
      Throws:
      IllegalArgumentException - Exception raised whenever top-left or bottom-right corners lie outside current matrix instance, or if top-left corner is indeed located below or at right side of bottom-right corner.

    • setSubmatrix

      public void setSubmatrix(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, double[] values, boolean isColumnOrder)
      Copies elements from provided array into this matrix at provided location. Elements in array are copied into this matrix following provided order (either row or column order).
      Parameters:
      topLeftRow - Top-left row index where copy starts.
      topLeftColumn - Top-left column index where copy ends.
      bottomRightRow - Bottom-right row index where copy ends.
      bottomRightColumn - Bottom-right column index where copy ends.
      values - Array to be copied.
      isColumnOrder - If true values are copied consecutively from array following column order on the destination matrix, otherwise row order is used.
      Throws:
      IllegalArgumentException - Exception raised whenever top-left or bottom-right corners lie outside current matrix instance, or if top-left corner is indeed located below or at right side of bottom-right corner.

    • setSubmatrix

      public void setSubmatrix(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, double[] values, int valuesStart, int valuesEnd)
      Copies elements from provided array into this matrix at provided location. Elements in array are copied into this matrix considering DEFAULT_USE_COLUMN_ORDER starting at provided location until end provided position.
      Parameters:
      topLeftRow - Top-left row index where copy starts (inclusive).
      topLeftColumn - Top-left column index where copy starts (inclusive).
      bottomRightRow - Bottom-right row index where copy ends (inclusive).
      bottomRightColumn - Bottom-right column index where copy ends. (inclusive)
      values - Array to be copied.
      valuesStart - Position where copy from array will start (inclusive).
      valuesEnd - Position where copy from array will finish (inclusive).
      Throws:
      IllegalArgumentException - Exception raised whenever top-left or bottom-right corners lie outside current matrix instance, or if top-left corner is indeed located below or at right side of bottom-right corner, or if valuesStart and valuesEnd lie outside valid array positions or start is greater than end position.

    • setSubmatrix

      public void setSubmatrix(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, double[] values, int valuesStart, int valuesEnd, boolean isColumnOrder)
      Copies elements from provided array into this matrix at provided location. Elements in array are copied into this matrix following provided order (either row or column order) starting at provided location until end provided position.
      Parameters:
      topLeftRow - Top-left row index where copy starts (inclusive)
      topLeftColumn - Top-left column index where copy starts (inclusive)
      bottomRightRow - Bottom-right row index where copy ends (inclusive)
      bottomRightColumn - Bottom-right column index where copy ends. (inclusive)
      values - Array to be copied.
      valuesStart - Position where copy from array will start (inclusive).
      valuesEnd - Position where copy from array will finish (inclusive).
      isColumnOrder - If true values are copied consecutively from array following column order on the destination matrix, otherwise row order is used.
      Throws:
      IllegalArgumentException - Exception raised whenever top-left or bottom-right corners lie outside current matrix instance, or if top-left corner is indeed located below or at right side of bottom-right corner, or if valuesStart and valuesEnd lie outside valid array positions or start is greater than end position.

    • identity

      public static void identity(Matrix m)
      Sets values into provided matrix to make it an identity matrix (all elements in the diagonal equal to one, and remaining elements to zero).
      Parameters:
      m - Matrix where identity values are set.

    • identity

      public static Matrix identity(int rows, int columns) throws WrongSizeException
      Creates and returns a new matrix instance having all the elements on the diagonal equal to one and the remaining ones equal to zero.
      Parameters:
      rows - Number of rows of created instance
      columns - Number of columns of created instance
      Returns:
      An identity matrix
      Throws:
      WrongSizeException - Raised if either rows or columns is equal to zero

    • fillWithUniformRandomValues

      public static void fillWithUniformRandomValues(double minValue, double maxValue, Random random, Matrix result)
      Fills provided matrix with random uniform values ranging from minValue to maxValue.
      Parameters:
      minValue - Minimum value of uniform random generated values
      maxValue - Maximum value of uniform random generated values
      random - Random generator
      result - Matrix where random values are stored.
      Throws:
      IllegalArgumentException - if minValue <= maxValue
      NullPointerException - if either provided random or result instances are null

    • fillWithUniformRandomValues

      public static void fillWithUniformRandomValues(double minValue, double maxValue, Matrix result)
      Fills provided matrix with random uniform values ranging from minValue to maxValue.
      Parameters:
      minValue - Minimum value of uniform random generated values
      maxValue - Maximum value of uniform random generated values
      result - Matrix where random values are stored
      Throws:
      IllegalArgumentException - if minValue <= maxValue
      NullPointerException - if provided result matrix is null

    • createWithUniformRandomValues

      public static Matrix createWithUniformRandomValues(int rows, int columns, double minValue, double maxValue) throws WrongSizeException
      Creates new matrix instance using provided size and containing uniformly distributed random values with provided range.
      Parameters:
      rows - Number of rows of instantiated matrix
      columns - Number of columns of instantiated matrix
      minValue - Minimum value of uniform random generated values
      maxValue - Maximum value of uniform random generated values
      Returns:
      A new matrix containing uniform random values
      Throws:
      WrongSizeException - Exception thrown if either rows or columns is zero, or if the minimum random value is greater or equal than the maximum random value
      IllegalArgumentException - if minValue <= maxValue

    • createWithUniformRandomValues

      public static Matrix createWithUniformRandomValues(int rows, int columns, double minValue, double maxValue, Random random) throws WrongSizeException
      Creates new matrix instance using provided size and containing uniformly distributed random values with provided range and using provided random generator
      Parameters:
      rows - Number of rows of instantiated matrix
      columns - Number of columns of instantiated matrix
      minValue - Minimum value of uniform random generated values
      maxValue - Maximum value of uniform random generated values
      random - A random generator.
      Returns:
      A new matrix containing uniform random values
      Throws:
      WrongSizeException - Exception thrown if either rows or columns is zero, or if the minimum random value is greater or equal than the maximum random value
      IllegalArgumentException - if minValue <= maxValue

    • fillWithGaussianRandomValues

      public static void fillWithGaussianRandomValues(double mean, double standardDeviation, Random random, Matrix result)
      Fills provided matrix with random Gaussian values with provided mean and standard deviation.
      Parameters:
      mean - Mean value of generated random values
      standardDeviation - Standard deviation of generated random values
      random - Random generator
      result - Matrix where random values are stored
      Throws:
      IllegalArgumentException - if standard deviation is negative or zero
      NullPointerException - if provided result matrix is null

    • fillWithGaussianRandomValues

      public static void fillWithGaussianRandomValues(double mean, double standardDeviation, Matrix result)
      Fills provided matrix with random Gaussian values with provided mean and standard deviation
      Parameters:
      mean - Mean value of generated random values
      standardDeviation - Standard deviation of generated random values
      result - Matrix where random values are stored
      Throws:
      IllegalArgumentException - if standard deviation is negative or zero
      NullPointerException - if provided result matrix is null

    • createWithGaussianRandomValues

      public static Matrix createWithGaussianRandomValues(int rows, int columns, double mean, double standardDeviation) throws WrongSizeException
      Creates new matrix instance using provided size and containing gaussian/normal distributed random values with provided median and standard deviation.
      Parameters:
      rows - Number of rows of instantiated matrix
      columns - Number of columns of instantiated matrix
      mean - Mean value of gaussian random generated values
      standardDeviation - Standard deviation of gaussian random generated values
      Returns:
      A new matrix containing gaussian random values
      Throws:
      WrongSizeException - Exception thrown if either rows or columns is zero, or if the standard deviation is negative or zero.
      IllegalArgumentException - thrown if provided standard deviation is negative or zero.

    • createWithGaussianRandomValues

      public static Matrix createWithGaussianRandomValues(int rows, int columns, double mean, double standardDeviation, Random random) throws WrongSizeException
      Creates new matrix instance using provided size and containing gaussian/normal distributed random values with provided median and standard deviation and using provided random generator
      Parameters:
      rows - Number of rows of instantiated matrix
      columns - Number of columns of instantiated matrix
      mean - Mean value of gaussian random generated values
      standardDeviation - Standard deviation of gaussian random generated values
      random - A random generator.
      Returns:
      A new matrix containing gaussian random values
      Throws:
      WrongSizeException - Exception thrown if either rows or columns is zero, or if the standard deviation is negative or zero.
      IllegalArgumentException - thrown if provided standard deviation is negative or zero.

    • diagonal

      public static void diagonal(double[] diagonal, Matrix result)
      Makes provided result matrix a diagonal matrix containing provided elements in the diagonal. Elements outside the diagonal will be set to zero
      Parameters:
      diagonal - Array containing the elements to be set on the diagonal
      result - Matrix where values are stored
      Throws:
      NullPointerException - Exception thrown if provided parameters are null

    • diagonal

      public static Matrix diagonal(double[] diagonal)
      Creates a diagonal matrix having all the elements in provided array in its diagonal and the remaining elements equal to zero. Returned matrix will have size n x n, where n is the length of the array
      Parameters:
      diagonal - Array containing the elements to be set on the diagonal
      Returns:
      A diagonal matrix
      Throws:
      NullPointerException - Raised if provided diagonal array is null

    • newFromArray

      public static Matrix newFromArray(double[] array)
      Instantiates new matrix from array using DEFAULT_USE_COLUMN_ORDER
      Parameters:
      array - Array used as source to copy values from
      Returns:
      Returns matrix created from array

    • newFromArray

      public static Matrix newFromArray(double[] array, boolean isColumnOrder)
      Instantiates new matrix from array using either column or row order
      Parameters:
      array - Array used as source to copy values from
      isColumnOrder - True if column order must be used, false otherwise
      Returns:
      Returns matrix created from array

    • fromArray

      public void fromArray(double[] array) throws WrongSizeException
      Copies elements of array into this instance using column order.
      Parameters:
      array - array to copy values from.
      Throws:
      WrongSizeException - if provided array length is not equal to the number of rows multiplied per the number of columns of this instance.

    • fromArray

      public void fromArray(double[] array, boolean isColumnOrder) throws WrongSizeException
      Copies elements of array into this instance using provided order.
      Parameters:
      array - array to copy values from.
      isColumnOrder - true to use column order, false otherwise.
      Throws:
      WrongSizeException - if provided array length is not equal to the number of rows multiplied per the number of columns of this instance.

    • symmetrize

      public void symmetrize(Matrix result) throws WrongSizeException
      Symmetrizes this instance and stores the result into provided instance. Symmetrization is done by averaging this instance with its transpose (i.e. S = (M+M')/2
      Parameters:
      result - instance where symmetrized version of this instance will be stored.
      Throws:
      WrongSizeException - if this instance is not square or provided result instance doesn't have the same size as this instance.

    • symmetrizeAndReturnNew

      public Matrix symmetrizeAndReturnNew() throws WrongSizeException
      Symmetrizes this instance and returns the result as a new matrix instance. Symmetrization is done by averaging this instance with its transpose (i.e. S = (M+M')/2
      Returns:
      a new symmetrizes version of this instance.
      Throws:
      WrongSizeException - if this instance is not square.

    • symmetrize

      public void symmetrize() throws WrongSizeException
      Symmetrizes this instance and updates it with computed value. Symmetrization is done by averaging this instance with its transpose (i.e. S = (M+M')/2
      Throws:
      WrongSizeException - if this instance is not square.

    • internalAdd

      private void internalAdd(Matrix other, Matrix result)
      Method to internally add two matrices.
      Parameters:
      other - Matrix to be added to current matrix
      result - Matrix where result will be stored.

    • internalSubtract

      private void internalSubtract(Matrix other, Matrix result)
      Method to internally subtract two matrices.
      Parameters:
      other - Matrix to be subtracted from current matrix.
      result - Matrix where result will be stored.

    • internalMultiply

      private void internalMultiply(Matrix other, double[] resultBuffer, int[] resultColumnIndex)
      Method to internally multiply two matrices.
      Parameters:
      other - Matrix to be multiplied to current matrix
      resultBuffer - Matrix buffer of data where result will be stored.
      resultColumnIndex - Array of matrix column indices where result will be stored.

    • internalMultiply

      private void internalMultiply(Matrix other, Matrix result)
      Method to internally multiply two matrices.
      Parameters:
      other - Matrix to be multiplied to current matrix.
      result - Matrix where result will be stored.

    • internalMultiplyKronecker

      private void internalMultiplyKronecker(Matrix other, double[] resultBuffer, int[] resultColumnIndex)
      Method to internally compute the Kronecker product between two matrices.
      Parameters:
      other - other matrix to be Kronecker multiplied to current matrix.
      resultBuffer - matrix buffer of data where result will be stored.
      resultColumnIndex - array of matrix column indices where result will be stored.

    • internalMultiplyKronecker

      private void internalMultiplyKronecker(Matrix other, Matrix result)
      Method to internally compute the Kronecker product between two matrices.
      Parameters:
      other - other matrix to be Kronecker multiplied to current matrix.
      result - matrix where result will be stored.

    • internalElementByElementProduct

      private void internalElementByElementProduct(Matrix other, Matrix result)
      Method to internally compute element by element product of two matrices.
      Parameters:
      other - Matrix to be element by element multiplied to current matrix
      result - Matrix where result will be stored.

    • internalTranspose

      private void internalTranspose(double[] resultBuffer, int[] resultColumnIndex)
      Method to internally compute matrix transposition.
      Parameters:
      resultBuffer - Buffer where transposed matrix data is stored.
      resultColumnIndex - Buffer where indices of transposed matrix data is stored.

    • internalTranspose

      private void internalTranspose(Matrix result)
      Method to internally compute matrix transposition.
      Parameters:
      result - Matrix where transposed data is stored.

    • internalResize

      private void internalResize(int rows, int columns) throws WrongSizeException
      Method used internally to remove matrix contents and resizing it.
      Parameters:
      rows - Number of rows to be set
      columns - Number of columns to be set.
      Throws:
      WrongSizeException - Exception raised if either rows or columns is zero.

    • internalGetSubmatrix

      private void internalGetSubmatrix(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, Matrix result)
      Internal method to retrieve a sub-matrix of current matrix instance. Sub-matrix is obtained by copying all elements contained within provided coordinates (both top-left and bottom-right points are included within sub-matrix).
      Parameters:
      topLeftRow - Top-left row index where sub-matrix starts.
      topLeftColumn - Top-left column index where sub-matrix starts.
      bottomRightRow - Bottom-right row index where sub-matrix ends.
      bottomRightColumn - Bottom-right column index where sub-matrix ends.
      result - Instance where sub-matrix data is stored.

    • internalGetSubmatrixAsArray

      private void internalGetSubmatrixAsArray(int topLeftRow, int topLeftColumn, int bottomRightRow, int bottomRightColumn, boolean isColumnOrder, double[] result)
      Internal method to retrieve a sub-matrix of current matrix instance as an array of values using provided column order and storing the result in provided array. Sub-matrix is obtained by copying all elements contained within provided coordinates (both top-left and bottom-right points are included within sub-matrix).
      Parameters:
      topLeftRow - Top-left row index where sub-matrix starts
      topLeftColumn - Top-left column index where sub-matrix starts
      bottomRightRow - Bottom-right row index where sub-matrix ends
      bottomRightColumn - Bottom-right column index where sub-matrix ends.
      isColumnOrder - If true, picks elements from matrix using column order, otherwise row order is used.
      result - Array where sub-matrix data is stored.