# Class DiagonalSum

java.lang.Object
dev.nm.algebra.linear.matrix.doubles.operation.DiagonalSum
All Implemented Interfaces:
Matrix, MatrixAccess, MatrixRing, MatrixTable, AbelianGroup<Matrix>, Monoid<Matrix>, Ring<Matrix>, Table, DeepCopyable

public class DiagonalSum extends Object implements Matrix
Add diagonal elements to a matrix, an efficient implementation.
• ## Constructor Summary

Constructors
Constructor
Description
DiagonalSum(Matrix A, double d)

DiagonalSum(Matrix A, double[] d)

DiagonalSum(Matrix A, Vector d)

• ## Method Summary

Modifier and Type
Method
Description
Matrix
add(Matrix that)
this + that
Matrix
deepCopy()
The implementation returns an instance created from this by the copy constructor of the class, or just this if the instance itself is immutable.
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.
Matrix
minus(Matrix that)
this - that
Matrix
multiply(Matrix that)
this * that
Vector
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 i, int j, double value)
Set the matrix entry at [i,j] to a value.
Matrix
t()
Get the transpose of this matrix.
Matrix
ZERO()
Get a zero matrix that has the same dimension as this matrix.

### Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

### Methods inherited from interface dev.nm.algebra.linear.matrix.doubles.Matrix

toCSV
• ## Constructor Details

• ### DiagonalSum

public DiagonalSum(Matrix A, double[] d)
• ### DiagonalSum

public DiagonalSum(Matrix A, double d)
• ### DiagonalSum

public DiagonalSum(Matrix A, Vector d)
• ## Method Details

• ### multiply

public Vector multiply(Vector v)
Description copied from interface: Matrix
Right multiply this matrix, A, by a vector.
Specified by:
multiply in interface Matrix
Parameters:
v - a vector
Returns:
Av, a vector
• ### scaled

public Matrix scaled(double c)
Description copied from interface: Matrix
Scale this matrix, A, by a constant.
Specified by:
scaled in interface Matrix
Parameters:
c - a double
Returns:
cA
• ### 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 interface Matrix
Parameters:
i - the row index
Returns:
the vector A[i, ]
Throws:
MatrixAccessException - when i < 1, or when i > the number of rows
• ### 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 interface Matrix
Parameters:
j - the column index
Returns:
a vector A[, j]
Throws:
MatrixAccessException - when j < 1, or when j > the number of columns
• ### deepCopy

public Matrix deepCopy()
Description copied from interface: DeepCopyable
The implementation returns an instance created from this by the copy constructor of the class, or just this if the instance itself is immutable.
Specified by:
deepCopy in interface DeepCopyable
Specified by:
deepCopy in interface Matrix
Returns:
an independent (deep) copy of the instance
• ### nRows

public int nRows()
Description copied from interface: Table
Gets the number of rows. Rows count from 1.
Specified by:
nRows in interface Table
Returns:
the number of rows
• ### nCols

public int nCols()
Description copied from interface: Table
Gets the number of columns. Columns count from 1.
Specified by:
nCols in interface Table
Returns:
the number of columns
• ### set

public void set(int i, int j, 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 interface MatrixAccess
Parameters:
i - the row index
j - the column index
value - the value to set A[i,j] to
Throws:
MatrixAccessException - if i or j is out of range
• ### 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 interface MatrixAccess
Parameters:
i - the row index
j - the column index
Returns:
A[i,j]
Throws:
MatrixAccessException - if i or j is out of range
• ### 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 interface MatrixRing
Returns:
the transpose of this matrix

Description copied from interface: MatrixRing
this + that
Specified by:
add in interface AbelianGroup<Matrix>
Specified by:
add in interface MatrixRing
Parameters:
that - a matrix
Returns:
the sum of this and that
• ### minus

public Matrix minus(Matrix that)
Description copied from interface: MatrixRing
this - that
Specified by:
minus in interface AbelianGroup<Matrix>
Specified by:
minus in interface MatrixRing
Parameters:
that - a matrix
Returns:
the difference between this and that
• ### multiply

public Matrix multiply(Matrix that)
Description copied from interface: MatrixRing
this * that
Specified by:
multiply in interface MatrixRing
Specified by:
multiply in interface Monoid<Matrix>
Parameters:
that - a matrix
Returns:
the product ofthis and that
• ### opposite

public Matrix opposite()
Description copied from interface: MatrixRing
Get the opposite of this matrix.
Specified by:
opposite in interface AbelianGroup<Matrix>
Specified by:
opposite in interface MatrixRing
Returns:
-this
• ### 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 interface AbelianGroup<Matrix>
Specified by:
ZERO in interface MatrixRing
Returns:
the 0 matrix
• ### 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 interface MatrixRing
Specified by:
ONE in interface Monoid<Matrix>
Returns:
an identity matrix