Class UpperTriangPackMatrix

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

    public class UpperTriangPackMatrix
    extends AbstractMatrix
    Upper triangular packed matrix. In contrast with LowerTriangDenseMatrix, this matrix exploits the sparsity by only storing about half the matrix. As such, the triangular matrix

    a11 a12 a13 a14
      a22 a23 a24
        a33 a34
          a44

    is packed as follows:

    a11 a12 a22 a13 a23 a33 a14 a24 a34 a44

    • Constructor Detail

      • UpperTriangPackMatrix

        public UpperTriangPackMatrix​(int n)
        Constructor for UpperTriangPackMatrix
        Parameters:
        n - Size of the matrix. Since the matrix must be square, this equals both the number of rows and columns
      • UpperTriangPackMatrix

        public UpperTriangPackMatrix​(Matrix A)
        Constructor for UpperTriangPackMatrix
        Parameters:
        A - Matrix to copy contents from. Only the entries of the relevant part are copied
      • UpperTriangPackMatrix

        public UpperTriangPackMatrix​(Matrix A,
                                     boolean deep)
        Constructor for UpperTriangPackMatrix
        Parameters:
        A - Matrix to copy contents from. Only the entries of the relevant part are copied
        deep - True if the copy is deep, else false (giving a shallow copy). For shallow copies, A must be a packed 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
        Overrides:
        add in class AbstractMatrix
      • 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
        Overrides:
        set in class AbstractMatrix
      • get

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

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

        public double[] getData()
        Returns the matrix contents. Ordering depends on the underlying storage assumptions
      • 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