org.apache.sysml.runtime.matrix.data

Class SparseRow

java.lang.Object

org.apache.sysml.runtime.matrix.data.SparseRow

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

SparseRowScalar, SparseRowVector

public abstract class SparseRow
extends Object
implements Serializable

Base class for sparse row implementations such as sparse row vectors and sparse scalars (single value per row).

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
SparseRow()

Method Summary

Modifier and Type	Method and Description
abstract boolean	add(int col, double v) Add a value to a specified column with awareness of potential insertions.
abstract void	append(int col, double v) Appends a value to the end of the sparse row.
abstract void	compact() In-place compaction of non-zero-entries; removes zero entries and shifts non-zero entries to the left if necessary.
abstract double	get(int col) Gets the value of a specified column.
abstract int[]	indexes() Get the index array of non-zero entries, co-aligned with the array of values.
abstract boolean	isEmpty() Indicates if the sparse row is empty, i.e., if is has size zero.
abstract void	reset(int estnns, int maxnns) Resets the sparse row to empty, after this call size and isEmpty are guaranteed to return 0 and true, respectively.
abstract boolean	set(int col, double v) Sets the value of a specified column with awareness of potential overwrites or deletes (set to value zero).
abstract int	size() Get the number of non-zero values of the sparse row.
abstract void	sort() In-place sort of column-index value pairs in order to allow binary search after constant-time append was used for reading unordered sparse rows.
String	toString()
abstract double[]	values() Get the value array of non-zero entries, co-aligned with the array of indexes.

Methods inherited from class java.lang.Object

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

Constructor Detail

SparseRow

public SparseRow()

Method Detail

size

public abstract int size()

Get the number of non-zero values of the sparse row.

Returns:

number of non-zeros

isEmpty

public abstract boolean isEmpty()

Indicates if the sparse row is empty, i.e., if is has size zero.

Returns:

true if empty

values

public abstract double[] values()

Get the value array of non-zero entries, co-aligned with the array of indexes.

Returns:

array of values

indexes

public abstract int[] indexes()

Get the index array of non-zero entries, co-aligned with the array of values.

Returns:

array of indexes

reset

public abstract void reset(int estnns,
                           int maxnns)

Resets the sparse row to empty, after this call size and isEmpty are guaranteed to return 0 and true, respectively.

Parameters:

estnns - estimated number of non-zeros

maxnns - maximum number of non-zeros, e.g., number of columns

set

public abstract boolean set(int col,
                            double v)

Sets the value of a specified column with awareness of potential overwrites or deletes (set to value zero).

Parameters:

col - column index, zero-based

v - value

Returns:

true if the size of the sparse row changed

add

public abstract boolean add(int col,
                            double v)

Add a value to a specified column with awareness of potential insertions.

Parameters:

col - column index, zero-based

v - value

Returns:

true if the size of the sparse row changed

append

public abstract void append(int col,
                            double v)

Appends a value to the end of the sparse row.

Parameters:

col - column index, zero-based

v - value

get

public abstract double get(int col)

Gets the value of a specified column. If the column index does not exist in the sparse row, this call returns zero.

Parameters:

col - column index, zero-based

Returns:

value

sort

public abstract void sort()

In-place sort of column-index value pairs in order to allow binary search after constant-time append was used for reading unordered sparse rows. We first check if already sorted and subsequently sort if necessary in order to get O(n) best case. Note: In-place sort is necessary in order to guarantee the memory estimate for operations that implicitly read that data set.

compact

public abstract void compact()

In-place compaction of non-zero-entries; removes zero entries and shifts non-zero entries to the left if necessary.

toString

public String toString()

Overrides:

toString in class Object