Package no.uib.cipr.matrix
Class BandMatrix
- java.lang.Object
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- no.uib.cipr.matrix.AbstractMatrix
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- no.uib.cipr.matrix.BandMatrix
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- All Implemented Interfaces:
java.lang.Iterable<MatrixEntry>
,Matrix
public class BandMatrix extends AbstractMatrix
Banded matrix. The banded matrix is a useful sparse structure for many kinds of direct computations, however it should only be used if the band is sufficiently narrow as wide bands actually wastes both memory and compute time. The matrixa11 a12 a21 a22 a23 a31 a32 a33 a34 a42 a43 a44 a45 a53 a54 a55 has two lower diagonals and one upper diagonal. It will be stored in the array
a11 a21 a31 a21 a22 a32 a42 a23 a33 a43 a53 a34 a44 a54 a45 a55 Empty cells are allocated, but never referenced.
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Nested Class Summary
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Nested classes/interfaces inherited from interface no.uib.cipr.matrix.Matrix
Matrix.Norm
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Field Summary
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Fields inherited from class no.uib.cipr.matrix.AbstractMatrix
numColumns, numRows
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Constructor Summary
Constructors Constructor Description BandMatrix(int n, int kl, int ku)
Constructor for BandMatrixBandMatrix(Matrix A, int kl, int ku)
Constructor for BandMatrixBandMatrix(Matrix A, int kl, int ku, boolean deep)
Constructor for BandMatrix
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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
BandMatrix
copy()
Creates a deep copy of the matrixdouble
get(int row, int column)
ReturnsA(row,column)
double[]
getData()
Returns the matrix contentsjava.util.Iterator<MatrixEntry>
iterator()
Vector
multAdd(double alpha, Vector x, Vector y)
y = alpha*A*x + y
int
numSubDiagonals()
Returns the number of lower diagonalsint
numSuperDiagonals()
Returns the number of upper diagonalsvoid
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
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, 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, 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, transMult, transMultAdd, transpose, transRank1, transRank1, transRank2, transRank2, transSolve, transSolve
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Constructor Detail
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BandMatrix
public BandMatrix(int n, int kl, int ku)
Constructor for BandMatrix- Parameters:
n
- Size of the matrix. Since the matrix must be square, this equals both the number of rows and columnskl
- Number of bands above the main diagonal (superdiagonals)ku
- Number of bands below the main diagonal (subdiagonals)
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BandMatrix
public BandMatrix(Matrix A, int kl, int ku)
Constructor for BandMatrix- Parameters:
A
- Matrix to copy contents from. Only the parts ofA
that lie within the allocated band are copied over, the rest is ignoredkl
- Number of bands above the main diagonal (superdiagonals)ku
- Number of bands below the main diagonal (subdiagonals)
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BandMatrix
public BandMatrix(Matrix A, int kl, int ku, boolean deep)
Constructor for BandMatrix- Parameters:
A
- Matrix to copy contents from. Only the parts ofA
that lie within the allocated band are copied over, the rest is ignoredkl
- Number of bands above the main diagonal (superdiagonals)ku
- Number of bands below the main diagonal (subdiagonals)deep
- True for a deep copy. For shallow copies,A
must be a banded matrix
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Method Detail
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copy
public BandMatrix copy()
Description copied from interface:Matrix
Creates a deep copy of the matrix- Specified by:
copy
in interfaceMatrix
- Overrides:
copy
in classAbstractMatrix
- Returns:
- A
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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.
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multAdd
public Vector multAdd(double alpha, Vector x, Vector y)
Description copied from interface:Matrix
y = alpha*A*x + y
- Specified by:
multAdd
in interfaceMatrix
- Overrides:
multAdd
in classAbstractMatrix
x
- Vector of sizeA.numColumns()
y
- Vector of sizeA.numRows()
- Returns:
- y
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transMultAdd
public Vector transMultAdd(double alpha, Vector x, Vector y)
Description copied from interface:Matrix
y = alpha*AT*x + y
- Specified by:
transMultAdd
in interfaceMatrix
- Overrides:
transMultAdd
in classAbstractMatrix
x
- Vector of sizeA.numRows()
y
- Vector of sizeA.numColumns()
- Returns:
- y
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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 throwUnsupportedOperationException
. Note that it is often more efficient to use a matrix decomposition and its associated solver- Specified by:
solve
in interfaceMatrix
- Overrides:
solve
in classAbstractMatrix
- Parameters:
B
- Matrix with the same number of rows asA
, and the same number of columns asX
X
- Matrix with a number of rows equalA.numColumns()
, and the same number of columns asB
- Returns:
- X
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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 throwUnsupportedOperationException
. Note that it is often more efficient to use a matrix decomposition and its associated solver- Specified by:
solve
in interfaceMatrix
- Overrides:
solve
in classAbstractMatrix
- Parameters:
b
- Vector of sizeA.numRows()
x
- Vector of sizeA.numColumns()
- Returns:
- x
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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 interfaceMatrix
- Overrides:
transpose
in classAbstractMatrix
- Returns:
- This matrix
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getData
public double[] getData()
Returns the matrix contents
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add
public void add(int row, int column, double value)
Description copied from interface:Matrix
A(row,column) += value
- Specified by:
add
in interfaceMatrix
- Overrides:
add
in classAbstractMatrix
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set
public void set(int row, int column, double value)
Description copied from interface:Matrix
A(row,column) = value
- Specified by:
set
in interfaceMatrix
- Overrides:
set
in classAbstractMatrix
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get
public double get(int row, int column)
Description copied from interface:Matrix
ReturnsA(row,column)
- Specified by:
get
in interfaceMatrix
- Overrides:
get
in classAbstractMatrix
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numSubDiagonals
public int numSubDiagonals()
Returns the number of lower diagonals
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numSuperDiagonals
public int numSuperDiagonals()
Returns the number of upper diagonals
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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 interfaceMatrix
- Overrides:
set
in classAbstractMatrix
- Returns:
- A
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iterator
public java.util.Iterator<MatrixEntry> iterator()
- Specified by:
iterator
in interfacejava.lang.Iterable<MatrixEntry>
- Overrides:
iterator
in classAbstractMatrix
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