RandomMatrix (Java Statistical Analysis Tool 0.0.8 API)

java.lang.Object
- jsat.linear.Matrix
- - jsat.linear.GenericMatrix
  - - jsat.linear.RandomMatrix

All Implemented Interfaces:

Serializable, Cloneable
```
public abstract class RandomMatrix
extends GenericMatrix
```
Stores a Matrix full of random values in constant O(1) space by re-computing all matrix values on the fly as need. This allows memory reduction and use when it is necessary to use the matrix with a large sparse data set, where some matrix values may never even be used - or used very infrequently.

This method is most useful when:
- A random matrix can not be fit into main memory
- An in memory matrix with the model being trained would result in swapping , in which case the slower Random Matrix would be faster since it can avoid swapping
- A very large matrix must be synchronized across many threads or machines. The Random Matrix takes O(1) space and is thread safe
- Initializing a random dense matrix
- The accesses of the matrix is sparse enough that not all matrix values will get used, or used very infrequently
Because the values of the random matrix are computed on the fly, the Random Matrix can not be altered. If attempted, an exception will be thrown.

Because a Random Matric can not be altered, it can not fulfill the contract of getMatrixOfSameType(int, int). For this reason, it will return a DenseMatrix so that use cases of the given method do not break, and can return new - altered - matrices.
Author:

Edward Raff

See Also:

Serialized Form

Field Summary
- Fields inherited from class jsat.linear.GenericMatrix
  NB2

Constructor Summary

Constructors
Constructor and Description
`RandomMatrix(int rows, int cols)` Creates a new random matrix object
`RandomMatrix(int rows, int cols, long seedMult)` Creates a new random matrix object
`RandomMatrix(RandomMatrix toCopy)` Copy constructor

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`canBeMutated()` Indicates whether or not this matrix can be mutated.
`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.
`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 A_i,j
`protected Matrix`	`getMatrixOfSameType(int rows, int cols)` Creates a new matrix of the same type
`protected abstract double`	`getVal(Random rand)` Computes the value of an index given the already initialized `Random` object.
`boolean`	`isSparce()` Returns `true` if the matrix is sparse, `false` otherwise
`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 A_i,j

Methods inherited from class jsat.linear.GenericMatrix
clone, lup, lup, multiply, multiply, multiply, multiplyTranspose, multiplyTranspose, mutableAdd, mutableAdd, mutableAdd, mutableAdd, mutableMultiply, mutableMultiply, mutableTranspose, qr, qr, swapRows, transpose, transposeMultiply, transposeMultiply, transposeMultiply, zeroOut

Methods inherited from class jsat.linear.Matrix
add, add, add, add, canMultiply, copyTo, diag, diagMult, diagMult, equals, equals, eye, getColumn, getColumnView, getRow, getRowView, increment, 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, updateRow

Methods inherited from class java.lang.Object
finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - RandomMatrix
```
public RandomMatrix(int rows,
                    int cols)
```
    Creates a new random matrix object
    
    Parameters:
    
    rows - the number of rows for the random matrix
    
    cols - the number of columns for the random matrix
  - RandomMatrix
```
public RandomMatrix(int rows,
                    int cols,
                    long seedMult)
```
    Creates a new random matrix object
    
    Parameters:
    
    rows - the number of rows for the random matrix
    
    cols - the number of columns for the random matrix
    
    seedMult - a value to multiply with the seed used for each individual index. It should be a large value
  - RandomMatrix
```
public RandomMatrix(RandomMatrix toCopy)
```
    Copy constructor
    
    Parameters:
    
    toCopy - the object to copy
- Method Detail
  - getMatrixOfSameType
```
protected Matrix getMatrixOfSameType(int rows,
                                     int cols)
```
    Description copied from class: GenericMatrix
    
    Creates a new matrix of the same type
    
    Specified by:
    
    getMatrixOfSameType in class GenericMatrix
    
    Parameters:
    
    rows - the number of rows for the matrix to have
    
    cols - the number of columns for the matrix to have
    
    Returns:
    
    the empty all zero new matrix
  - getVal
```
protected abstract double getVal(Random rand)
```
    Computes the value of an index given the already initialized Random object. This is called by the get(int, int) method, and will make sure that the correct seed is set before calling this method.
    
    Parameters:
    
    rand - the PRNG to generate the index value from
    
    Returns:
    
    the value for a given index based on the given PRNG
  - 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
  - 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
  - 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
  - canBeMutated
```
public boolean canBeMutated()
```
    Description copied from class: Matrix
    
    Indicates whether or not this matrix can be mutated. If false, any method that contains "mutate" will not work.
    
    By default, this returns true
    
    Overrides:
    
    canBeMutated in class Matrix
    
    Returns:
    
    true if the matrix supports being altered, false other wise.
  - 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.

Class RandomMatrix

Field Summary

Fields inherited from class jsat.linear.GenericMatrix

Constructor Summary

Method Summary

Methods inherited from class jsat.linear.GenericMatrix

Methods inherited from class jsat.linear.Matrix

Methods inherited from class java.lang.Object

Constructor Detail

RandomMatrix

RandomMatrix

RandomMatrix

Method Detail

getMatrixOfSameType

getVal

get

set

rows

cols

isSparce

canBeMutated

changeSize