Class LowerSymmBandMatrix

  • All Implemented Interfaces:
    java.lang.Iterable<MatrixEntry>, Matrix
    Direct Known Subclasses:
    LowerSPDBandMatrix

    public class LowerSymmBandMatrix
    extends AbstractMatrix
    Lower symmetrical banded matrix. The same storage as BandMatrix, but without superdiagonals. Upper part of the matrix is implictly known by symmetry
    • Constructor Detail

      • LowerSymmBandMatrix

        public LowerSymmBandMatrix​(int n,
                                   int kd)
        Constructor for LowerSymmBandMatrix
        Parameters:
        n - Size of the matrix. Since the matrix must be square, this equals both the number of rows and columns
        kd - Number of bands off the main diagonal (off diagonals)
      • LowerSymmBandMatrix

        public LowerSymmBandMatrix​(Matrix A,
                                   int kd)
        Constructor for LowerSymmBandMatrix
        Parameters:
        A - Matrix to copy contents from. Only the parts of A that lie within the allocated band are copied over, the rest is ignored
        kd - Number of bands off the main diagonal (off diagonals)
      • LowerSymmBandMatrix

        public LowerSymmBandMatrix​(Matrix A,
                                   int kd,
                                   boolean deep)
        Constructor for LowerSymmBandMatrix
        Parameters:
        A - Matrix to copy contents from. Only the parts of A that lie within the allocated band are copied over, the rest is ignored
        kd - Number of bands off the main diagonal (off diagonals)
        deep - True for a deep copy. For shallow copies, A must be a banded matrix
    • Method Detail

      • add

        public void add​(int row,
                        int column,
                        double value)
        Description copied from interface: Matrix
        A(row,column) += value
        Specified by:
        add in interface Matrix
      • get

        public double get​(int row,
                          int column)
        Description copied from interface: Matrix
        Returns A(row,column)
        Specified by:
        get in interface Matrix
      • set

        public void set​(int row,
                        int column,
                        double value)
        Description copied from interface: Matrix
        A(row,column) = value
        Specified by:
        set in interface Matrix
      • multAdd

        public Vector multAdd​(double alpha,
                              Vector x,
                              Vector y)
        Description copied from interface: Matrix
        y = alpha*A*x + y
        Specified by:
        multAdd in interface Matrix
        Overrides:
        multAdd in class AbstractMatrix
        x - Vector of size A.numColumns()
        y - Vector of size A.numRows()
        Returns:
        y
      • iterator

        public java.util.Iterator<MatrixEntry> iterator()
        Specified by:
        iterator in interface java.lang.Iterable<MatrixEntry>
      • solve

        public Matrix solve​(Matrix B,
                            Matrix X)
        Description copied from interface: Matrix
        X = A\B. Not all matrices support this operation, those that do not throw UnsupportedOperationException. Note that it is often more efficient to use a matrix decomposition and its associated solver
        Specified by:
        solve in interface Matrix
        Overrides:
        solve in class AbstractMatrix
        Parameters:
        B - Matrix with the same number of rows as A, and the same number of columns as X
        X - Matrix with a number of rows equal A.numColumns(), and the same number of columns as B
        Returns:
        X
      • solve

        public Vector solve​(Vector b,
                            Vector x)
        Description copied from interface: Matrix
        x = A\b. Not all matrices support this operation, those that do not throw UnsupportedOperationException. Note that it is often more efficient to use a matrix decomposition and its associated solver
        Specified by:
        solve in interface Matrix
        Overrides:
        solve in class AbstractMatrix
        Parameters:
        b - Vector of size A.numRows()
        x - Vector of size A.numColumns()
        Returns:
        x
      • transSolve

        public Matrix transSolve​(Matrix B,
                                 Matrix X)
        Description copied from interface: Matrix
        X = AT\B. Not all matrices support this operation, those that do not throw UnsupportedOperationException. Note that it is often more efficient to use a matrix decomposition and its associated transpose solver
        Specified by:
        transSolve in interface Matrix
        Overrides:
        transSolve in class AbstractMatrix
        Parameters:
        B - Matrix with a number of rows equal A.numColumns(), and the same number of columns as X
        X - Matrix with the same number of rows as A, and the same number of columns as B
        Returns:
        X
      • transSolve

        public Vector transSolve​(Vector b,
                                 Vector x)
        Description copied from interface: Matrix
        x = AT\b. Not all matrices support this operation, those that do not throw UnsupportedOperationException. Note that it is often more efficient to use a matrix decomposition and its associated solver
        Specified by:
        transSolve in interface Matrix
        Overrides:
        transSolve in class AbstractMatrix
        Parameters:
        b - Vector of size A.numColumns()
        x - Vector of size A.numRows()
        Returns:
        x
      • transpose

        public Matrix transpose()
        Description copied from interface: Matrix
        Transposes the matrix in-place. In most cases, the matrix must be square for this to work.
        Specified by:
        transpose in interface Matrix
        Overrides:
        transpose in class AbstractMatrix
        Returns:
        This matrix
      • getData

        public double[] getData()
        Returns the matrix contents
      • numSubDiagonals

        public int numSubDiagonals()
        Returns the number of lower diagonals
      • numSuperDiagonals

        public int numSuperDiagonals()
        Returns the number of upper diagonals
      • zero

        public Matrix zero()
        Description copied from interface: Matrix
        Zeros all the entries in the matrix, while preserving any underlying structure. Useful for general, unstructured matrices.
        Specified by:
        zero in interface Matrix
        Overrides:
        zero in class AbstractMatrix
        Returns:
        A