no.uib.cipr.matrix.sparse

Class LinkedSparseMatrix

java.lang.Object

no.uib.cipr.matrix.AbstractMatrix

no.uib.cipr.matrix.sparse.LinkedSparseMatrix

All Implemented Interfaces:

Iterable<MatrixEntry>, Matrix

public class LinkedSparseMatrix
extends AbstractMatrix

A Linked List (with shortcuts to important nodes) implementation of an n x m Matrix with z elements that has a typical O(z / m) insertion / lookup cost and an iterator that traverses columns then rows: a good fit for unstructured sparse matrices. A secondary link maintains fast transpose iteration.

However, memory requirements ( 1 instance (8 bytes), 2 int (16 bytes), 2 ref (16 bytes), 1 double (8 bytes) = 48 bytes per matrix element, plus 8 x numcol + 8 x numrow bytess for the cache) are slightly higher than structured sparse matrix storage. Note that on 32 bit JVMs, or on 64 bit JVMs with CompressedOops enabled, references and ints only cost 4 bytes each, bringing the cost to 28 bytes per element.

Author:

Sam Halliday

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 and Description
LinkedSparseMatrix(int numRows, int numColumns)
LinkedSparseMatrix(Matrix A)
LinkedSparseMatrix(MatrixVectorReader r)

Method Summary

Modifier and Type	Method and Description
Matrix	copy() Creates a deep copy of the matrix
double	get(int row, int column) Returns A(row,column)
Iterator<MatrixEntry>	iterator()
Matrix	multAdd(double alpha, Matrix B, Matrix C) C = alpha*A*B + C
Vector	multAdd(double alpha, Vector x, Vector y) y = alpha*A*x + y
Matrix	scale(double alpha) A = alpha*A
void	set(int row, int column, double value) A(row,column) = value
Matrix	transABmultAdd(double alpha, Matrix B, Matrix C) C = alpha*AT*BT + C
Matrix	transAmultAdd(double alpha, Matrix B, Matrix C) C = alpha*AT*B + C
Matrix	transBmultAdd(double alpha, Matrix B, Matrix C) C = alpha*A*BT + C
Vector	transMultAdd(double alpha, Vector x, Vector y) y = alpha*AT*x + y
Matrix	transpose() Transposes the matrix in-place.
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, 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, mult, multAdd, multAdd, norm, norm1, normF, normInf, numColumns, numRows, rank1, rank1, rank1, rank1, rank1, rank1, rank2, rank2, rank2, rank2, set, set, solve, solve, toString, transABmult, transABmult, transABmultAdd, transAmult, transAmult, transAmultAdd, transBmult, transBmult, transBmultAdd, transMult, transMult, transMultAdd, transpose, transRank1, transRank1, transRank2, transRank2, transSolve, transSolve

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

LinkedSparseMatrix

public LinkedSparseMatrix(int numRows,
                          int numColumns)

LinkedSparseMatrix

public LinkedSparseMatrix(Matrix A)

LinkedSparseMatrix

public LinkedSparseMatrix(MatrixVectorReader r)
                   throws IOException

Throws:

IOException

Method Detail

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

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

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

iterator

public Iterator<MatrixEntry> iterator()

Specified by:

iterator in interface Iterable<MatrixEntry>

Overrides:

iterator in class AbstractMatrix

scale

public Matrix scale(double alpha)

Description copied from interface: Matrix

A = alpha*A

Specified by:

scale in interface Matrix

Overrides:

scale in class AbstractMatrix

Returns:

A

copy

public Matrix 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

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

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

transMultAdd

public Vector transMultAdd(double alpha,
                           Vector x,
                           Vector y)

Description copied from interface: Matrix

y = alpha*AT*x + y

Specified by:

transMultAdd in interface Matrix

Overrides:

transMultAdd in class AbstractMatrix

x - Vector of size A.numRows()

y - Vector of size A.numColumns()

Returns:

y

multAdd

public Matrix multAdd(double alpha,
                      Matrix B,
                      Matrix C)

Description copied from interface: Matrix

C = alpha*A*B + C

Specified by:

multAdd in interface Matrix

Overrides:

multAdd in class AbstractMatrix

B - Matrix such that B.numRows() == A.numColumns() and B.numColumns() == C.numColumns()

C - Matrix such that C.numRows() == A.numRows() and B.numColumns() == C.numColumns()

Returns:

C

transBmultAdd

public Matrix transBmultAdd(double alpha,
                            Matrix B,
                            Matrix C)

Description copied from interface: Matrix

C = alpha*A*BT + C

Specified by:

transBmultAdd in interface Matrix

Overrides:

transBmultAdd in class AbstractMatrix

B - Matrix such that B.numRows() == A.numRows() and B.numColumns() == C.numColumns()

C - Matrix such that C.numRows() == A.numColumns() and B.numColumns() == C.numColumns()

Returns:

C

transAmultAdd

public Matrix transAmultAdd(double alpha,
                            Matrix B,
                            Matrix C)

Description copied from interface: Matrix

C = alpha*AT*B + C

Specified by:

transAmultAdd in interface Matrix

Overrides:

transAmultAdd in class AbstractMatrix

B - Matrix such that B.numRows() == A.numRows() and B.numColumns() == C.numColumns()

C - Matrix such that C.numRows() == A.numColumns() and B.numColumns() == C.numColumns()

Returns:

C

transABmultAdd

public Matrix transABmultAdd(double alpha,
                             Matrix B,
                             Matrix C)

Description copied from interface: Matrix

C = alpha*AT*BT + C

Specified by:

transABmultAdd in interface Matrix

Overrides:

transABmultAdd in class AbstractMatrix

B - Matrix such that B.numColumns() == A.numRows() and B.numRows() == C.numColumns()

C - Matrix such that C.numRows() == A.numColumns() and B.numRows() == C.numColumns()

Returns:

C