jsat.linear

Class MatrixOfVecs

java.lang.Object

jsat.linear.Matrix

jsat.linear.GenericMatrix

jsat.linear.MatrixOfVecs

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable

public class MatrixOfVecs
extends GenericMatrix

This class provides a base mechanism to create a Matrix 'view' from a list of Vec objects. The vector objects will be used to back the rows of the matrix, so changes to one are shown in the other. If the matirx is altered using changeSize(int, int), this may no longer be true.
Row oriented operations are implemented to defer to the base vector objects used.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
MatrixOfVecs(int rows, int cols, boolean sparse) Creates a new Matrix of Vecs of the desired size.
MatrixOfVecs(java.util.List<Vec> rows) Creates a new Matrix of Vecs from the given list of Vec objects.
MatrixOfVecs(Vec... rows) Creates a new Matrix of Vecs from the given array of Vec objects.

Method Summary

Modifier and Type	Method and Description
void	changeSize(int newRows, int newCols) This method alters the size of a matrix, either adding or subtracting rows from the internal structure of the matrix.
MatrixOfVecs	clone()
int	cols() Returns the number of columns stored in this matrix
double	get(int i, int j) Returns the value stored at at the matrix position Ai,j
Vec	getRowView(int r) Obtains a vector that is backed by this, at very little memory cost.
void	increment(int i, int j, double value) Alters the current matrix at index (i,j) to be equal to Ai,j = Ai,j + value
boolean	isSparce() Returns true if the matrix is sparse, false otherwise
void	multiply(Vec b, double z, Vec c) If this matrix is Am x n, and b has a length of n, and c has a length of m, then this will mutate c to store c = c + A*b*z
void	mutableAdd(double c) Alters the current matrix to store the value A+c
void	mutableMultiply(double c) Alters the current matrix to be equal to A*c
int	rows() Returns the number of rows stored in this matrix
void	set(int i, int j, double value) Sets the value stored at at the matrix position Ai,j
void	updateRow(int i, double c, Vec b) Alters row i of this matrix, such that A[i,:] = A[i,:] + c*b
void	zeroOut() Alters the current matrix so that all values are equal to zero.

Methods inherited from class jsat.linear.GenericMatrix

lup, lup, multiply, multiply, multiplyTranspose, multiplyTranspose, mutableAdd, mutableAdd, mutableAdd, mutableMultiply, mutableTranspose, qr, qr, swapRows, transpose, transposeMultiply, transposeMultiply, transposeMultiply

Methods inherited from class jsat.linear.Matrix

add, add, add, add, canBeMutated, canMultiply, copyTo, diag, diagMult, diagMult, equals, equals, eye, getColumn, getColumnView, getRow, isSquare, isSymmetric, isSymmetric, multiply, multiply, multiply, multiply, multiply, multiplyTranspose, multiplyTranspose, mutableAdd, mutableAdd, mutableSubtract, mutableSubtract, mutableSubtract, mutableSubtract, mutableSubtract, mutableSubtract, nnz, OuterProductUpdate, OuterProductUpdate, pascal, random, sameDimensions, subtract, subtract, subtract, subtract, toString, transpose, transposeMultiply, transposeMultiply, transposeMultiply

Methods inherited from class java.lang.Object

getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

MatrixOfVecs

public MatrixOfVecs(Vec... rows)

Creates a new Matrix of Vecs from the given array of Vec objects. All Vec objects contained should be of the same length.

Parameters:

rows - the rows of vecs to make this matrix.

MatrixOfVecs

public MatrixOfVecs(java.util.List<Vec> rows)

Creates a new Matrix of Vecs from the given list of Vec objects. All Vec objects contained should be of the same length.

Parameters:

rows - the rows of vecs to make this matrix.

MatrixOfVecs

public MatrixOfVecs(int rows,
                    int cols,
                    boolean sparse)

Creates a new Matrix of Vecs of the desired size.

Parameters:

rows - the number of rows in the matrix

cols - the number of columns in the matrix

sparse - if true SparseVector objects will be used for the rows. Else DenseVector will be used.

Method Detail

changeSize

public void changeSize(int newRows,
                       int newCols)

Description copied from class: Matrix

This method alters the size of a matrix, either adding or subtracting rows from the internal structure of the matrix. Every resize call may cause a new allocation internally, and should not be called for excessive changing of a matrix. All added rows/ columns will have values of zero. If a row / column is removed, it is always the bottom/right most row / column removed. Values of the removed rows / columns will be lost.

Specified by:

changeSize in class Matrix

Parameters:

newRows - the new number of rows, must be positive

newCols - the new number of columns, must be positive.

get

public double get(int i,
                  int j)

Description copied from class: Matrix

Returns the value stored at at the matrix position A_i,j

Specified by:

get in class Matrix

Parameters:

i - the row, starting from 0

j - the column, starting from 0

Returns:

the value at A_i,j

set

public void set(int i,
                int j,
                double value)

Description copied from class: Matrix

Sets the value stored at at the matrix position A_i,j

Specified by:

set in class Matrix

Parameters:

i - the row, starting from 0

j - the column, starting from 0

value - the value to place at A_i,j

increment

public void increment(int i,
                      int j,
                      double value)

Description copied from class: Matrix

Alters the current matrix at index (i,j) to be equal to A_i,j = A_i,j + value

Overrides:

increment in class Matrix

Parameters:

i - the row, starting from 0

j - the column, starting from 0

value - the value to add to the matrix coordinate

rows

public int rows()

Description copied from class: Matrix

Returns the number of rows stored in this matrix

Specified by:

rows in class Matrix

Returns:

the number of rows stored in this matrix

cols

public int cols()

Description copied from class: Matrix

Returns the number of columns stored in this matrix

Specified by:

cols in class Matrix

Returns:

the number of columns stored in this matrix

getRowView

public Vec getRowView(int r)

Description copied from class: Matrix

Obtains a vector that is backed by this, at very little memory cost. Mutations to this vector will alter the values stored in the matrix, and vice versa.

Overrides:

getRowView in class Matrix

Parameters:

r - the row to obtain a view of

Returns:

a vector backed by the specified row of the matrix

updateRow

public void updateRow(int i,
                      double c,
                      Vec b)

Description copied from class: Matrix

Alters row i of this matrix, such that A[i,:] = A[i,:] + c*b

Overrides:

updateRow in class Matrix

Parameters:

i - the index of the row to update

c - the scalar constant to multiply the vector by

b - the vector to add to the specified row

multiply

public void multiply(Vec b,
                     double z,
                     Vec c)

Description copied from class: Matrix

If this matrix is A_{m x n}, and b has a length of n, and c has a length of m, then this will mutate c to store c = c + A*b*z

Overrides:

multiply in class GenericMatrix

Parameters:

b - the vector to be treated as a colum vector

z - the constant to multiply the A*b value by.

c - where to place the result by addition

mutableMultiply

public void mutableMultiply(double c)

Description copied from class: Matrix

Alters the current matrix to be equal to A*c

Overrides:

mutableMultiply in class GenericMatrix

Parameters:

c - the scalar constant to multiply by

mutableAdd

public void mutableAdd(double c)

Description copied from class: Matrix

Alters the current matrix to store the value A+c

Overrides:

mutableAdd in class GenericMatrix

Parameters:

c - the scalar constant to add to this

zeroOut

public void zeroOut()

Description copied from class: Matrix

Alters the current matrix so that all values are equal to zero.

Overrides:

zeroOut in class GenericMatrix

clone

public MatrixOfVecs clone()

Overrides:

clone in class GenericMatrix

isSparce

public boolean isSparce()

Description copied from class: Matrix

Returns true if the matrix is sparse, false otherwise

Specified by:

isSparce in class Matrix

Returns:

true if the matrix is sparse, false otherwise