java.lang.Object
- no.uib.cipr.matrix.AbstractMatrix
- - no.uib.cipr.matrix.LowerTriangPackMatrix

All Implemented Interfaces:

java.lang.Iterable<MatrixEntry>, Matrix

Direct Known Subclasses:

UnitLowerTriangPackMatrix
```
public class LowerTriangPackMatrix
extends AbstractMatrix
```
Lower 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

a₂₁ a₂₂

a₃₁ a₃₂ a₃₃

a₄₁ a₄₂ a₄₃ a₄₄

is packed as follows:

a₁₁ a₂₁ a₃₁ a₄₁ a₂₂ a₃₂ a₄₂ a₃₃ a₄₃ a₄₄

Nested Class Summary
- Nested classes/interfaces inherited from interface no.uib.cipr.matrix.Matrix
  Matrix.Norm

Field Summary
- Fields inherited from class no.uib.cipr.matrix.AbstractMatrix
  numColumns, numRows

Constructor Summary

Constructors
Constructor	Description
`LowerTriangPackMatrix(int n)`	Constructor for LowerTriangPackMatrix
`LowerTriangPackMatrix(Matrix A)`	Constructor for LowerTriangPackMatrix
`LowerTriangPackMatrix(Matrix A, boolean deep)`	Constructor for LowerTriangPackMatrix

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`add(int row, int column, double value)`	`A(row,column) += value`
`LowerTriangPackMatrix`	`copy()`	Creates a deep copy of the matrix
`double`	`get(int row, int column)`	Returns `A(row,column)`
`double[]`	`getData()`	Returns the matrix contents.
`java.util.Iterator<MatrixEntry>`	`iterator()`
`Vector`	`mult(double alpha, Vector x, Vector y)`	`y = alphaAx`
`void`	`set(int row, int column, double value)`	`A(row,column) = value`
`Matrix`	`set(Matrix B)`	`A=B`.
`Matrix`	`solve(Matrix B, Matrix X)`	`X = A\B`.
`Vector`	`solve(Vector b, Vector x)`	`x = A\b`.
`Vector`	`transMult(double alpha, Vector x, Vector y)`	`y = alphaA^Tx`
`Matrix`	`transSolve(Matrix B, Matrix X)`	`X = A^T\B`.
`Vector`	`transSolve(Vector b, Vector x)`	`x = A^T\b`.
`Matrix`	`zero()`	Zeros all the entries in the matrix, while preserving any underlying structure.

Methods inherited from class no.uib.cipr.matrix.AbstractMatrix
add, add, check, checkMultAdd, checkMultAdd, checkRank1, checkRank1, checkRank2, checkRank2, checkSize, checkSolve, checkSolve, checkTransABmultAdd, checkTransAmultAdd, checkTransBmultAdd, checkTransMultAdd, checkTranspose, checkTranspose, checkTransRank1, checkTransRank2, isSquare, max, max, mult, mult, mult, multAdd, multAdd, multAdd, multAdd, norm, norm1, normF, normInf, numColumns, numRows, rank1, rank1, rank1, rank1, rank1, rank1, rank2, rank2, rank2, rank2, scale, set, toString, transABmult, transABmult, transABmultAdd, transABmultAdd, transAmult, transAmult, transAmultAdd, transAmultAdd, transBmult, transBmult, transBmultAdd, transBmultAdd, transMult, transMultAdd, transMultAdd, transpose, transpose, transRank1, transRank1, transRank2, transRank2

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.lang.Iterable
forEach, spliterator

- Constructor Detail
  - LowerTriangPackMatrix
```
public LowerTriangPackMatrix(int n)
```
    Constructor for LowerTriangPackMatrix
    
    Parameters:
    
    n - Size of the matrix. Since the matrix must be square, this equals both the number of rows and columns
  - LowerTriangPackMatrix
```
public LowerTriangPackMatrix(Matrix A)
```
    Constructor for LowerTriangPackMatrix
    
    Parameters:
    
    A - Matrix to copy contents from. Only the entries of the relevant part are copied
  - LowerTriangPackMatrix
```
public LowerTriangPackMatrix(Matrix A,
                             boolean deep)
```
    Constructor for LowerTriangPackMatrix
    
    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
  - copy
```
public LowerTriangPackMatrix copy()
```
    Description copied from interface: Matrix
    
    Creates a deep copy of the matrix
    
    Specified by:
    
    copy in interface Matrix
    
    Overrides:
    
    copy in class AbstractMatrix
    
    Returns:
    
    A
  - 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
  - transMult
```
public Vector transMult(double alpha,
                        Vector x,
                        Vector y)
```
    Description copied from interface: Matrix
    
    y = alpha*A^T*x
    
    Specified by:
    
    transMult in interface Matrix
    
    Overrides:
    
    transMult in class AbstractMatrix
    
    x - Vector of size A.numRows()
    
    y - Vector of size A.numColumns()
    
    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 = A^T\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 = A^T\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
  - iterator
```
public java.util.Iterator<MatrixEntry> iterator()
```
    Specified by:
    
    iterator in interface java.lang.Iterable<MatrixEntry>
    
    Overrides:
    
    iterator in class AbstractMatrix
  - getData
```
public double[] getData()
```
    Returns the matrix contents. Ordering depends on the underlying storage assumptions
  - set
```
public Matrix set(Matrix B)
```
    Description copied from interface: Matrix
    
    A=B. The matrices must be of the same size
    
    Specified by:
    
    set in interface Matrix
    
    Overrides:
    
    set in class AbstractMatrix
    
    Returns:
    
    A
  - 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

a₁₁
a₂₁	a₂₂
a₃₁	a₃₂	a₃₃
a₄₁	a₄₂	a₄₃	a₄₄

Class LowerTriangPackMatrix

Nested Class Summary

Nested classes/interfaces inherited from interface no.uib.cipr.matrix.Matrix

Field Summary

Fields inherited from class no.uib.cipr.matrix.AbstractMatrix

Constructor Summary

Method Summary

Methods inherited from class no.uib.cipr.matrix.AbstractMatrix

Methods inherited from class java.lang.Object

Methods inherited from interface java.lang.Iterable

Constructor Detail

LowerTriangPackMatrix

LowerTriangPackMatrix

LowerTriangPackMatrix

Method Detail

add

set

get

copy

mult

transMult

solve

solve

transSolve

transSolve

iterator

getData

set

zero