Package org.ejml.data

Class FMatrixRMaj

  • All Implemented Interfaces:
    java.io.Serializable, FMatrix, Matrix, ReshapeMatrix

    public class FMatrixRMaj
    extends FMatrix1Row

    FMatrixRMaj is a row matrix with real elements that are 32-bit floats. A matrix is the fundamental data structure in linear algebra. Unlike a sparse matrix, there is no compression in a row matrix and every element is stored in memory. This allows for fast reads and writes to the matrix.

    The matrix is stored internally in a row-major 1D array format:

    data[ y*numCols + x ] = data[y][x]

    For example:
    data =

     a[0]  a[1]   a[2]   a[3]
     a[4]  a[5]   a[6]   a[7]
     a[8]  a[9]   a[10]  a[11]
     a[12] a[13]  a[14]  a[15]
     
    See Also:
    Serialized Form
    • Constructor Summary

      Constructors 
      Constructor Description
      FMatrixRMaj()
      Default constructor in which nothing is configured.
      FMatrixRMaj​(float[] data)
      Creates a column vector the same length as this array
      FMatrixRMaj​(float[][] data)
      Creates a matrix with the values and shape defined by the 2D array 'data'.
      FMatrixRMaj​(int length)
      This declares an array that can store a matrix up to the specified length.
      FMatrixRMaj​(int numRows, int numCols)
      Creates a new Matrix with the specified shape whose elements initially have the value of zero.
      FMatrixRMaj​(int numRows, int numCols, boolean rowMajor, float... data)
      Creates a new matrix which has the same value as the matrix encoded in the provided array.
      FMatrixRMaj​(FMatrix mat)
      Creates a new FMatrixRMaj which contains the same information as the provided Matrix64F.
      FMatrixRMaj​(FMatrixRMaj orig)
      Creates a new matrix which is equivalent to the provided matrix.
    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void add​(int row, int col, float value)
      Adds 'value' to the specified element in the matrix.

      aij = aij + value
      FMatrixRMaj copy()
      Creates and returns a matrix which is idential to this one.
      FMatrixRMaj create​(int numRows, int numCols)
      Creates a new matrix of the same type with the specified shape
      FMatrixRMaj createLike()
      Creates a new matrix with the same shape as this matrix
      float get​(int row, int col)
      Returns the value of the specified matrix element.
      int getIndex​(int row, int col)
      Returns the internal array index for the specified row and column.
      int getNumElements()
      Returns the number of elements in this matrix, which is equal to the number of rows times the number of columns.
      MatrixType getType()
      Returns the type of matrix
      boolean isInBounds​(int row, int col)
      Determines if the specified element is inside the bounds of the Matrix.
      void reshape​(int numRows, int numCols, boolean saveValues)
      Changes the number of rows and columns in the matrix, allowing its size to grow or shrink.
      void set​(float[][] input)
      Assigns this matrix using a 2D array representation
      void set​(int numRows, int numCols, boolean rowMajor, float... data)
      Sets this matrix equal to the matrix encoded in the array.
      void set​(int row, int col, float value)
      Assigns the element in the Matrix to the specified value.
      void set​(Matrix original)
      Sets this matrix to be identical to the 'original' matrix passed in.
      java.lang.String toString()
      Converts the array into a string format for display purposes.
      float unsafe_get​(int row, int col)
      Same as FMatrix.get(int, int) but does not perform bounds check on input parameters.
      void unsafe_set​(int row, int col, float value)
      Same as FMatrix.set(int, int, float) but does not perform bounds check on input parameters.
      static FMatrixRMaj wrap​(int numRows, int numCols, float[] data)
      Creates a new FMatrixRMaj around the provided data.
      void zero()
      Sets all elements equal to zero.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
    • Constructor Detail

      • FMatrixRMaj

        public FMatrixRMaj​(int numRows,
                           int numCols,
                           boolean rowMajor,
                           float... data)

        Creates a new matrix which has the same value as the matrix encoded in the provided array. The input matrix's format can either be row-major or column-major.

        Note that 'data' is a variable argument type, so either 1D arrays or a set of numbers can be passed in:
        DenseMatrix a = new DenseMatrix(2,2,true,new float[]{1,2,3,4});
        DenseMatrix b = new DenseMatrix(2,2,true,1,2,3,4);

        Both are equivalent.

        Parameters:
        numRows - The number of rows.
        numCols - The number of columns.
        rowMajor - If the array is encoded in a row-major or a column-major format.
        data - The formatted 1D array. Not modified.
      • FMatrixRMaj

        public FMatrixRMaj​(float[][] data)

        Creates a matrix with the values and shape defined by the 2D array 'data'. It is assumed that 'data' has a row-major formatting:

        data[ row ][ column ]

        Parameters:
        data - 2D array representation of the matrix. Not modified.
      • FMatrixRMaj

        public FMatrixRMaj​(float[] data)
        Creates a column vector the same length as this array
        Parameters:
        data - elements in vector. copied
      • FMatrixRMaj

        public FMatrixRMaj​(int numRows,
                           int numCols)
        Creates a new Matrix with the specified shape whose elements initially have the value of zero.
        Parameters:
        numRows - The number of rows in the matrix.
        numCols - The number of columns in the matrix.
      • FMatrixRMaj

        public FMatrixRMaj​(FMatrixRMaj orig)
        Creates a new matrix which is equivalent to the provided matrix. Note that the length of the data will be determined by the shape of the matrix.
        Parameters:
        orig - The matrix which is to be copied. This is not modified or saved.
      • FMatrixRMaj

        public FMatrixRMaj​(int length)
        This declares an array that can store a matrix up to the specified length. This is use full when a matrix's size will be growing and it is desirable to avoid reallocating memory.
        Parameters:
        length - The size of the matrice's data array.
      • FMatrixRMaj

        public FMatrixRMaj()
        Default constructor in which nothing is configured. THIS IS ONLY PUBLICLY ACCESSIBLE SO THAT THIS CLASS CAN BE A JAVA BEAN. DON'T USE IT UNLESS YOU REALLY KNOW WHAT YOU'RE DOING!
      • FMatrixRMaj

        public FMatrixRMaj​(FMatrix mat)
        Creates a new FMatrixRMaj which contains the same information as the provided Matrix64F.
        Parameters:
        mat - Matrix whose values will be copied. Not modified.
    • Method Detail

      • wrap

        public static FMatrixRMaj wrap​(int numRows,
                                       int numCols,
                                       float[] data)
        Creates a new FMatrixRMaj around the provided data. The data must encode a row-major matrix. Any modification to the returned matrix will modify the provided data.
        Parameters:
        numRows - Number of rows in the matrix.
        numCols - Number of columns in the matrix.
        data - Data that is being wrapped. Referenced Saved.
        Returns:
        A matrix which references the provided data internally.
      • reshape

        public void reshape​(int numRows,
                            int numCols,
                            boolean saveValues)
        Description copied from class: FMatrixD1

        Changes the number of rows and columns in the matrix, allowing its size to grow or shrink. If the saveValues flag is set to true, then the previous values will be maintained, but reassigned to new elements in a row-major ordering. If saveValues is false values will only be maintained when the requested size is less than or equal to the internal array size. The primary use for this function is to encourage data reuse and avoid unnecessarily declaring and initialization of new memory.

        Examples:
        [ 1 2 ; 3 4 ] → reshape( 2 , 3 , true ) = [ 1 2 3 ; 4 0 0 ]
        [ 1 2 ; 3 4 ] → reshape( 1 , 2 , true ) = [ 1 2 ]
        [ 1 2 ; 3 4 ] → reshape( 1 , 2 , false ) = [ 1 2 ]
        [ 1 2 ; 3 4 ] → reshape( 2 , 3 , false ) = [ 0 0 0 ; 0 0 0 ]

        Specified by:
        reshape in class FMatrixD1
        Parameters:
        numRows - The new number of rows in the matrix.
        numCols - The new number of columns in the matrix.
        saveValues - If true then the value of each element will be save using a row-major reordering. Typically this should be false.
      • set

        public void set​(int row,
                        int col,
                        float value)

        Assigns the element in the Matrix to the specified value. Performs a bounds check to make sure the requested element is part of the matrix.

        aij = value

        Parameters:
        row - The row of the element.
        col - The column of the element.
        value - The element's new value.
      • unsafe_set

        public void unsafe_set​(int row,
                               int col,
                               float value)
        Description copied from interface: FMatrix
        Same as FMatrix.set(int, int, float) but does not perform bounds check on input parameters. This results in about a 25% speed increase but potentially sacrifices stability and makes it more difficult to track down simple errors. It is not recommended that this function be used, except in highly optimized code where the bounds are implicitly being checked.
        Parameters:
        row - Matrix element's row index..
        col - Matrix element's column index.
        value - The element's new value.
      • add

        public void add​(int row,
                        int col,
                        float value)

        Adds 'value' to the specified element in the matrix.

        aij = aij + value

        Parameters:
        row - The row of the element.
        col - The column of the element.
        value - The value that is added to the element
      • get

        public float get​(int row,
                         int col)
        Returns the value of the specified matrix element. Performs a bounds check to make sure the requested element is part of the matrix.
        Parameters:
        row - The row of the element.
        col - The column of the element.
        Returns:
        The value of the element.
      • unsafe_get

        public float unsafe_get​(int row,
                                int col)
        Description copied from interface: FMatrix
        Same as FMatrix.get(int, int) but does not perform bounds check on input parameters. This results in about a 25% speed increase but potentially sacrifices stability and makes it more difficult to track down simple errors. It is not recommended that this function be used, except in highly optimized code where the bounds are implicitly being checked.
        Parameters:
        row - Matrix element's row index..
        col - Matrix element's column index.
        Returns:
        The specified element's value.
      • getIndex

        public int getIndex​(int row,
                            int col)
        Description copied from class: FMatrixD1
        Returns the internal array index for the specified row and column.
        Specified by:
        getIndex in class FMatrixD1
        Parameters:
        row - Row index.
        col - Column index.
        Returns:
        Internal array index.
      • isInBounds

        public boolean isInBounds​(int row,
                                  int col)
        Determines if the specified element is inside the bounds of the Matrix.
        Parameters:
        row - The element's row.
        col - The element's column.
        Returns:
        True if it is inside the matrices bound, false otherwise.
      • getNumElements

        public int getNumElements()
        Returns the number of elements in this matrix, which is equal to the number of rows times the number of columns.
        Returns:
        The number of elements in the matrix.
      • set

        public void set​(int numRows,
                        int numCols,
                        boolean rowMajor,
                        float... data)
        Sets this matrix equal to the matrix encoded in the array.
        Parameters:
        numRows - The number of rows.
        numCols - The number of columns.
        rowMajor - If the array is encoded in a row-major or a column-major format.
        data - The formatted 1D array. Not modified.
      • zero

        public void zero()
        Sets all elements equal to zero.
      • copy

        public FMatrixRMaj copy()
        Creates and returns a matrix which is idential to this one.
        Returns:
        A new identical matrix.
      • set

        public void set​(Matrix original)
        Description copied from interface: Matrix
        Sets this matrix to be identical to the 'original' matrix passed in.
      • toString

        public java.lang.String toString()

        Converts the array into a string format for display purposes. The conversion is done using MatrixIO.print(java.io.PrintStream, FMatrix).

        Overrides:
        toString in class java.lang.Object
        Returns:
        String representation of the matrix.
      • createLike

        public FMatrixRMaj createLike()
        Description copied from interface: Matrix
        Creates a new matrix with the same shape as this matrix
      • create

        public FMatrixRMaj create​(int numRows,
                                  int numCols)
        Description copied from interface: Matrix
        Creates a new matrix of the same type with the specified shape
      • getType

        public MatrixType getType()
        Description copied from interface: Matrix
        Returns the type of matrix
      • set

        public void set​(float[][] input)
        Assigns this matrix using a 2D array representation
        Parameters:
        input - 2D array which this matrix will be set to