Class ImmutableMatrix
- java.lang.Object
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- dev.nm.algebra.linear.matrix.doubles.ImmutableMatrix
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- All Implemented Interfaces:
Matrix
,MatrixAccess
,MatrixRing
,MatrixTable
,AbelianGroup<Matrix>
,Monoid<Matrix>
,Ring<Matrix>
,Table
,DeepCopyable
public class ImmutableMatrix extends Object implements Matrix
This is a read-only view of aMatrix
instance. It keeps a reference to the matrix instance, delegates all operations to the instance except for set(int, int, double) which will always result in anMatrixAccessException
. Note that the returned values of all operations (e.g.,add()
) have the same types as the original matrix. Popular usages of this class include, e.g., thefinal
member of a class, the return value of a method. Note that the 'immutability' can be broken if the original matrix is modified. To avoid this, make a copy of the original matrix before passing it to the constructor. For example,ImmutableMatrix immutable = new ImmutableMatrix(m.deepCopy());
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Constructor Summary
Constructors Constructor Description ImmutableMatrix(Matrix A)
Construct a read-only version of a matrix.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description Matrix
add(Matrix that)
this + thatMatrix
deepCopy()
Make a deep copy of the underlying matrix.boolean
equals(Object obj)
double
get(int i, int j)
Get the matrix entry at [i,j].Vector
getColumn(int j)
Get the specified column in the matrix as a vector.Vector
getRow(int i)
Get the specified row in the matrix as a vector.int
hashCode()
Matrix
minus(Matrix that)
this - thatMatrix
multiply(Matrix that)
this * thatVector
multiply(Vector v)
Right multiply this matrix, A, by a vector.int
nCols()
Gets the number of columns.int
nRows()
Gets the number of rows.Matrix
ONE()
Get an identity matrix that has the same dimension as this matrix.Matrix
opposite()
Get the opposite of this matrix.Matrix
scaled(double c)
Scale this matrix, A, by a constant.void
set(int row, int col, double value)
Set the matrix entry at [i,j] to a value.Matrix
t()
Get the transpose of this matrix.String
toString()
Matrix
ZERO()
Get a zero matrix that has the same dimension as this matrix.
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Constructor Detail
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ImmutableMatrix
public ImmutableMatrix(Matrix A)
Construct a read-only version of a matrix. Note that changing the original matrix changes the "immutable" version as well.- Parameters:
A
- a matrix
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Method Detail
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set
public void set(int row, int col, double value) throws MatrixAccessException
Description copied from interface:MatrixAccess
Set the matrix entry at [i,j] to a value. This is the only method that may change a matrix.- Specified by:
set
in interfaceMatrixAccess
- Parameters:
row
- the row indexcol
- the column indexvalue
- the value to set A[i,j] to- Throws:
MatrixAccessException
- if i or j is out of range
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nRows
public int nRows()
Description copied from interface:Table
Gets the number of rows. Rows count from 1.
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nCols
public int nCols()
Description copied from interface:Table
Gets the number of columns. Columns count from 1.
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get
public double get(int i, int j) throws MatrixAccessException
Description copied from interface:MatrixAccess
Get the matrix entry at [i,j].- Specified by:
get
in interfaceMatrixAccess
- Parameters:
i
- the row indexj
- the column index- Returns:
- A[i,j]
- Throws:
MatrixAccessException
- if i or j is out of range
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getRow
public Vector getRow(int i) throws MatrixAccessException
Description copied from interface:Matrix
Get the specified row in the matrix as a vector.- Specified by:
getRow
in interfaceMatrix
- Parameters:
i
- the row index- Returns:
- the vector A[i, ]
- Throws:
MatrixAccessException
- when i < 1, or when i > the number of rows
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getColumn
public Vector getColumn(int j) throws MatrixAccessException
Description copied from interface:Matrix
Get the specified column in the matrix as a vector.- Specified by:
getColumn
in interfaceMatrix
- Parameters:
j
- the column index- Returns:
- a vector A[, j]
- Throws:
MatrixAccessException
- when j < 1, or when j > the number of columns
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add
public Matrix add(Matrix that)
Description copied from interface:MatrixRing
this + that- Specified by:
add
in interfaceAbelianGroup<Matrix>
- Specified by:
add
in interfaceMatrixRing
- Parameters:
that
- a matrix- Returns:
- the sum of
this
andthat
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minus
public Matrix minus(Matrix that)
Description copied from interface:MatrixRing
this - that- Specified by:
minus
in interfaceAbelianGroup<Matrix>
- Specified by:
minus
in interfaceMatrixRing
- Parameters:
that
- a matrix- Returns:
- the difference between
this
andthat
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multiply
public Matrix multiply(Matrix that)
Description copied from interface:MatrixRing
this * that- Specified by:
multiply
in interfaceMatrixRing
- Specified by:
multiply
in interfaceMonoid<Matrix>
- Parameters:
that
- a matrix- Returns:
- the product of
this
andthat
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multiply
public Vector multiply(Vector v)
Description copied from interface:Matrix
Right multiply this matrix, A, by a vector.
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scaled
public Matrix scaled(double c)
Description copied from interface:Matrix
Scale this matrix, A, by a constant.
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opposite
public Matrix opposite()
Description copied from interface:MatrixRing
Get the opposite of this matrix.- Specified by:
opposite
in interfaceAbelianGroup<Matrix>
- Specified by:
opposite
in interfaceMatrixRing
- Returns:
- -this
- See Also:
- Wikipedia: Additive inverse
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ZERO
public Matrix ZERO()
Description copied from interface:MatrixRing
Get a zero matrix that has the same dimension as this matrix.- Specified by:
ZERO
in interfaceAbelianGroup<Matrix>
- Specified by:
ZERO
in interfaceMatrixRing
- Returns:
- the 0 matrix
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ONE
public Matrix ONE()
Description copied from interface:MatrixRing
Get an identity matrix that has the same dimension as this matrix. For a non-square matrix, it zeros out the rows (columns) with index > nCols (nRows).- Specified by:
ONE
in interfaceMatrixRing
- Specified by:
ONE
in interfaceMonoid<Matrix>
- Returns:
- an identity matrix
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t
public Matrix t()
Description copied from interface:MatrixRing
Get the transpose of this matrix. This is the involution on the matrix ring.- Specified by:
t
in interfaceMatrixRing
- Returns:
- the transpose of this matrix
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deepCopy
public Matrix deepCopy()
Make a deep copy of the underlying matrix. The copy is no longer anImmutableMatrix
and may be mutable.- Specified by:
deepCopy
in interfaceDeepCopyable
- Specified by:
deepCopy
in interfaceMatrix
- Returns:
- a deep copy of the underlying matrix
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