Package io.github.andreipunko.math.matrix

Class Matrix2D

java.lang.Object
io.github.andreipunko.math.matrix.Matrix2D
Direct Known Subclasses:
MatrixXY
public class Matrix2D extends Object
Represents a two-dimensional matrix of real numbers with fixed dimensions. This class provides efficient storage and manipulation of matrix data using a single-dimensional array for better memory locality. It supports basic matrix operations such as element access, row/column swapping, and finding minimum/maximum values.

The matrix is stored internally as a single-dimensional array in row-major order, where the element at position (i,j) is stored at index i*n + j in the data array.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Matrix2D(int m, int n)
    Creates a new matrix with specified dimensions, initialized with zeros.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    fill(double d)
    Fills all elements of the matrix with the specified value.
    double
    get(int i, int j)
    Returns the value at the specified matrix position (i,j).
    double[]
    getRow(int i)
    Returns a copy of the specified row as an array.
    double
    max()
    Returns the maximum value stored in the matrix.
    double
    min()
    Returns the minimum value stored in the matrix.
    void
    set(int i, int j, double value)
    Sets a value at the specified matrix position (i,j).
    void
    setRow(int i, double[] arr)
    Sets an entire row of the matrix using the provided array.
    void
    swapCols(int n1, int n2)
    Swaps two columns of the matrix.
    void
    swapRows(int m1, int m2)
    Swaps two rows of the matrix.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Matrix2D

      public Matrix2D(int m, int n)
      Creates a new matrix with specified dimensions, initialized with zeros.
      Parameters:
      m - number of rows (must be positive)
      n - number of columns (must be positive)
      Throws:
      IllegalArgumentException - if m <= 0 or n <= 0

  • Method Details

    • set

      public void set(int i, int j, double value)
      Sets a value at the specified matrix position (i,j).
      Parameters:
      i - row index (0 <= i < m)
      j - column index (0 <= j < n)
      value - value to set
      Throws:
      IllegalArgumentException - if i < 0 or i >= m or j < 0 or j >= n

    • setRow

      public void setRow(int i, double[] arr)
      Sets an entire row of the matrix using the provided array.
      Parameters:
      i - row index (0 <= i < m)
      arr - array of n values to set in the row
      Throws:
      IllegalArgumentException - if i < 0 or i >= m or arr.length != n

    • getRow

      public double[] getRow(int i)
      Returns a copy of the specified row as an array.
      Parameters:
      i - row index (0 <= i < m)
      Returns:
      array containing the row elements
      Throws:
      IllegalArgumentException - if i < 0 or i >= m

    • get

      public double get(int i, int j)
      Returns the value at the specified matrix position (i,j).
      Parameters:
      i - row index (0 <= i < m)
      j - column index (0 <= j < n)
      Returns:
      value at position (i,j)
      Throws:
      IllegalArgumentException - if i < 0 or i >= m or j < 0 or j >= n

    • min

      public double min()
      Returns the minimum value stored in the matrix.
      Returns:
      minimum value

    • max

      public double max()
      Returns the maximum value stored in the matrix.
      Returns:
      maximum value

    • fill

      public void fill(double d)
      Fills all elements of the matrix with the specified value.
      Parameters:
      d - value to fill the matrix with

    • swapRows

      public void swapRows(int m1, int m2)
      Swaps two rows of the matrix.
      Parameters:
      m1 - index of the first row (0 <= m1 < m)
      m2 - index of the second row (0 <= m2 < m)
      Throws:
      IllegalArgumentException - if m1 < 0 or m1 >= m or m2 < 0 or m2 >= m or m1 = m2

    • swapCols

      public void swapCols(int n1, int n2)
      Swaps two columns of the matrix.
      Parameters:
      n1 - index of the first column (0 <= n1 < n)
      n2 - index of the second column (0 <= n2 < n)
      Throws:
      IllegalArgumentException - if n1 < 0 or n1 >= n or n2 < 0 or n2 >= n or n1 = n2